Initial work

To ensure that the prelude gets parsed with the same ItemId context as
normal REPL input

.gitignore

@@ -1,4 +1,3 @@
-Cargo.lock
 target
 .schala_repl
 .schala_history

Cargo.toml

@@ -7,6 +7,7 @@ authors = ["greg <greg.shuflin@protonmail.com>"]
 
 schala-repl = { path = "schala-repl" }
 schala-lang = { path = "schala-lang/language" }
+partis = { path="partis" }
 # maaru-lang = { path = "maaru" }
 # rukka-lang = { path = "rukka" }
 # robo-lang = { path = "robo" }

TODO.md

@@ -1,11 +1,37 @@
+# Plan of attack
+
+1. modify visitor so it can handle scopes
+  -this is needed both to handle import scope correctly
+  -and also to support making FQSNs aware of function parameters
+
+2. Once FQSNs are aware of function parameters, most of the Rc<String> things in eval.rs can go away
+
 # TODO items
 
+-use 'let' sigil in patterns for variables :
+
+```
+  q is MyStruct(let a, Chrono::Trigga) then {
+
+  }
+```
+
+-idea: what if there was something like React jsx syntas built in? i.e. a way to automatically transform some kind of markup
+into a function call, cf. `<h1 prop="arg">` ->  h1(prop=arg)
+
 ## General code cleanup
--experiment with storing metadata via ItemIds on AST nodes (cf. https://rust-lang.github.io/rustc-guide/hir.html, https://github.com/rust-lang/rust/blob/master/src/librustc/hir/mod.rs )
+- I think I can restructure the parser to get rid of most instances of expect!, at least at the beginning of a rule
+DONE -experiment with storing metadata via ItemIds on AST nodes (cf. https://rust-lang.github.io/rustc-guide/hir.html, https://github.com/rust-lang/rust/blob/master/src/librustc/hir/mod.rs )
 -implement and test open/use statements
 -implement field access
 - standardize on an error type that isn't String
 -implement a visitor pattern for the use of scope_resolver
+  - maybe implement this twice: 1) the value-returning, no-default one in the haoyi blogpost,
+  -look at https://gitlab.haskell.org/ghc/ghc/wikis/pattern-synonyms
+                                2) the non-value-returning, default one like in rustc (cf. https://github.com/rust-unofficial/patterns/blob/master/patterns/visitor.md)
+
+-parser error - should report subset of AST parsed *so far*
+  - what if you used python 'def' syntax to define a function? what error message makes sense here?
 
 ## Reduction
  - make a good type for actual language builtins to avoid string comparisons
@@ -74,10 +100,43 @@ ex.
 -consult http://gluon-lang.org/book/embedding-api.html
 
 
+## Trying if-syntax again
 
-## Playing around with conditional syntax ideas
+//simple if expr
+if x == 10 then "a" else "z"
+
+//complex if expr
+if x == 10 then {
+  let a = 1
+  let b = 2
+  a + b
+} else {
+  55
+}
+
+// different comparison ops
+if x {
+ == 1 then "a"
+  .isPrime() then "b"
+  else "c"
+}
+
+/* for now disallow `if x == { 1 then ... }`, b/c hard to parse
+
+//simple pattern-matching
+if x is Person("Ivan", age) then age else 0
+
+//match-block equivalent
+if x {
+ is Person("Ivan", _) then "Ivan"
+ is Person(_, age) if age > 13 then "barmitzvah'd"
+ else "foo"
+ }
+
+
+
+## (OLD) Playing around with conditional syntax ideas
 
-- 
 
 - if/match playground
 

partis/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "partis"
+version = "0.1.0"
+authors = ["greg <greg.shuflin@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

partis/src/lib.rs

@@ -0,0 +1,17 @@
+struct ParseError { }
+
+enum ParseResult<'a, T> {
+  Success(T, &'a str),
+  Failure(ParseError),
+  Incomplete,
+}
+
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+
+}

schala-lang/codegen/src/lib.rs

@@ -32,7 +32,11 @@ impl Fold for RecursiveDescentFn {
         if self.parse_level != 0 {
           self.parse_level -= 1;
         }
-        result
+
+        result.map_err(|mut parse_error: ParseError| {
+          parse_error.production_name = Some(stringify!(#ident).to_string());
+          parse_error
+        })
       }
     };
     i.block = Box::new(new_block);

schala-lang/language/Cargo.toml

@@ -13,6 +13,8 @@ failure = "0.1.5"
 ena = "0.11.0"
 stopwatch = "0.0.7"
 derivative = "1.0.3"
+colored = "1.8"
+radix_trie = "0.1.5"
 
 schala-lang-codegen = { path = "../codegen" }
 schala-repl = { path = "../../schala-repl" }

schala-lang/language/src/ast.rs

@@ -1,11 +1,14 @@
 use std::rc::Rc;
-use std::convert::From;
 
 use crate::derivative::Derivative;
-use crate::symbol_table::FullyQualifiedSymbolName;
 
+mod walker;
+mod visitor;
+mod visitor_test;
 mod operators;
 pub use operators::*;
+pub use visitor::ASTVisitor;
+pub use walker::walk_ast;
 
 /// An abstract identifier for an AST node
 #[derive(Debug, PartialEq, Eq, Hash, Clone)]
@@ -41,40 +44,6 @@ impl ItemIdStore {
   }
 }
 
-
-#[derive(Clone, Debug, PartialEq)]
-pub struct Meta<T> {
-  pub n: T,
-  pub fqsn: Option<FullyQualifiedSymbolName>
-}
-
-impl<T> Meta<T> {
-  pub fn new(n: T) -> Meta<T> {
-    Meta { n,
-    fqsn: None,
-    }
-  }
-
-  pub fn node(&self) -> &T {
-    &self.n
-  }
-
-  pub fn mut_node(&mut self) -> &mut T {
-    &mut self.n
-  }
-}
-
-//TODO this PartialEq is here to make tests work - find a way to make it not necessary
-#[derive(Clone, Debug, Default, PartialEq)]
-struct SourceMap {
-}
-
-impl From<Expression> for Meta<Expression> {
-  fn from(expr: Expression) -> Meta<Expression> {
-    Meta::new(expr)
-  }
-}
-
 #[derive(Derivative, Debug)]
 #[derivative(PartialEq)]
 pub struct AST {
@@ -94,7 +63,9 @@ pub struct Statement {
 #[derive(Debug, PartialEq, Clone)]
 pub enum StatementKind {
   Expression(Expression),
-  Declaration(Declaration), //TODO Declaration should also be Meta-wrapped; only Expression and Declaration are Meta-wrapped maybe?
+  Declaration(Declaration),
+  Import(ImportSpecifier),
+  Module(ModuleSpecifier),
 }
 
 pub type Block = Vec<Statement>;
@@ -124,7 +95,11 @@ pub enum Declaration {
     body: TypeBody,
     mutable: bool
   },
-  TypeAlias(Rc<String>, Rc<String>), //should have TypeSingletonName in it, or maybe just String, not sure
+  //TODO this needs to be more sophisticated
+  TypeAlias {
+    alias: Rc<String>,
+    original: Rc<String>,
+  },
   Binding {
     name: Rc<String>,
     constant: bool,
@@ -217,7 +192,7 @@ pub enum ExpressionKind {
     indexers: Vec<Expression>,
   },
   IfExpression {
-    discriminator: Box<Discriminator>,
+    discriminator: Option<Box<Expression>>,
     body: Box<IfExpressionBody>,
   },
   WhileExpression {
@@ -246,35 +221,33 @@ pub enum InvocationArgument {
   Ignored
 }
 
-#[derive(Debug, PartialEq, Clone)]
-pub enum Discriminator {
-  Simple(Expression),
-  BinOp(Expression, BinOp)
-}
-
 #[derive(Debug, PartialEq, Clone)]
 pub enum IfExpressionBody {
-  SimpleConditional(Block, Option<Block>),
-  SimplePatternMatch(Pattern, Block, Option<Block>),
-  GuardList(Vec<GuardArm>)
+  SimpleConditional {
+    then_case: Block,
+    else_case: Option<Block>
+  },
+  SimplePatternMatch {
+    pattern: Pattern,
+    then_case: Block,
+    else_case: Option<Block>
+  },
+  CondList(Vec<ConditionArm>)
 }
 
 #[derive(Debug, PartialEq, Clone)]
-pub struct GuardArm {
-  pub guard: Guard,
+pub struct ConditionArm {
+  pub condition: Condition,
+  pub guard: Option<Expression>,
   pub body: Block,
 }
 
 #[derive(Debug, PartialEq, Clone)]
-pub enum Guard {
-  Pat(Pattern),
-  HalfExpr(HalfExpr)
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct HalfExpr {
-  pub op: Option<BinOp>,
-  pub expr: ExpressionKind,
+pub enum Condition {
+  Pattern(Pattern),
+  TruncatedOp(BinOp, Expression),
+  Expression(Expression),
+  Else,
 }
 
 #[derive(Debug, PartialEq, Clone)]
@@ -308,3 +281,27 @@ pub enum ForBody {
   MonadicReturn(Expression),
   StatementBlock(Block),
 }
+
+#[derive(Debug, Derivative, Clone)]
+#[derivative(PartialEq)]
+pub struct ImportSpecifier {
+  #[derivative(PartialEq="ignore")]
+  pub id: ItemId,
+  pub path_components: Vec<Rc<String>>,
+  pub imported_names: ImportedNames
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum ImportedNames {
+  All,
+  LastOfPath,
+  List(Vec<Rc<String>>)
+}
+
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct ModuleSpecifier {
+  pub name: Rc<String>,
+  pub contents: Vec<Statement>,
+}
+

schala-lang/language/src/ast/operators.rs

@@ -68,10 +68,6 @@ impl BinOp {
     let s = token_kind_to_sigil(op_tok)?;
     Some(binop_precedences(s))
   }
-
-  pub fn get_precedence(&self) -> i32 {
-    binop_precedences(&self.sigil)
-  }
 }
 
 fn token_kind_to_sigil<'a>(tok: &'a TokenKind) -> Option<&'a str> {

schala-lang/language/src/ast/visitor.rs

@@ -0,0 +1,41 @@
+use std::rc::Rc;
+use crate::ast::*;
+
+//TODO maybe these functions should take closures that return a KeepRecursing | StopHere type,
+//or a tuple of (T, <that type>)
+
+pub trait ASTVisitor: Sized {
+  fn ast(&mut self, _ast: &AST) {}
+  fn block(&mut self, _statements: &Vec<Statement>) {}
+  fn statement(&mut self, _statement: &Statement) {}
+  fn declaration(&mut self, _declaration: &Declaration) {}
+  fn signature(&mut self, _signature: &Signature) {}
+  fn type_declaration(&mut self, _name: &TypeSingletonName, _body: &TypeBody, _mutable: bool) {}
+  fn type_alias(&mut self, _alias: &Rc<String>, _original: &Rc<String>) {}
+  fn binding(&mut self, _name: &Rc<String>, _constant: bool, _type_anno: Option<&TypeIdentifier>, _expr: &Expression) {}
+  fn implemention(&mut self, _type_name: &TypeIdentifier, _interface_name: Option<&TypeSingletonName>, _block: &Vec<Declaration>) {}
+  fn interface(&mut self, _name: &Rc<String>, _signatures: &Vec<Signature>) {}
+  fn expression(&mut self, _expression: &Expression) {}
+  fn expression_kind(&mut self, _kind: &ExpressionKind) {}
+  fn type_annotation(&mut self, _type_anno: Option<&TypeIdentifier>) {}
+  fn named_struct(&mut self, _name: &QualifiedName, _fields: &Vec<(Rc<String>, Expression)>) {}
+  fn call(&mut self, _f: &Expression, _arguments: &Vec<InvocationArgument>) {}
+  fn index(&mut self, _indexee: &Expression, _indexers: &Vec<Expression>) {}
+  fn if_expression(&mut self, _discrim: Option<&Expression>, _body: &IfExpressionBody) {}
+  fn condition_arm(&mut self, _arm: &ConditionArm) {}
+  fn while_expression(&mut self, _condition: Option<&Expression>, _body: &Block) {}
+  fn for_expression(&mut self, _enumerators: &Vec<Enumerator>, _body: &ForBody) {}
+  fn lambda(&mut self, _params: &Vec<FormalParam>, _type_anno: Option<&TypeIdentifier>, _body: &Block) {}
+  fn invocation_argument(&mut self, _arg: &InvocationArgument) {}
+  fn formal_param(&mut self, _param: &FormalParam) {}
+  fn import(&mut self, _import: &ImportSpecifier) {}
+  fn module(&mut self, _module: &ModuleSpecifier) {}
+  fn qualified_name(&mut self, _name: &QualifiedName) {}
+  fn nat_literal(&mut self, _n: u64) {}
+  fn float_literal(&mut self, _f: f64) {}
+  fn string_literal(&mut self, _s: &Rc<String>) {}
+  fn bool_literal(&mut self, _b: bool) {}
+  fn binexp(&mut self, _op: &BinOp, _lhs: &Expression, _rhs: &Expression) {}
+  fn prefix_exp(&mut self, _op: &PrefixOp, _arg: &Expression) {}
+  fn pattern(&mut self, _pat: &Pattern) {}
+}

schala-lang/language/src/ast/visitor_test.rs

@@ -0,0 +1,41 @@
+#![cfg(test)]
+
+use crate::ast::visitor::ASTVisitor;
+use crate::ast::walker;
+use crate::util::quick_ast;
+
+struct Tester {
+  count: u64,
+  float_count: u64
+}
+
+impl ASTVisitor for Tester {
+  fn nat_literal(&mut self, _n: u64) {
+    self.count += 1;
+  }
+  fn float_literal(&mut self, _f: f64) {
+    self.float_count += 1;
+  }
+}
+
+
+#[test]
+fn foo() {
+  let mut tester = Tester { count: 0, float_count: 0 };
+  let (ast, _) = quick_ast(r#"
+import gragh
+
+let a = 20 + 84
+let b = 28 + 1 + 2 + 2.0
+fn heh() {
+  let m = 9
+
+}
+
+"#);
+
+  walker::walk_ast(&mut tester, &ast);
+
+  assert_eq!(tester.count, 6);
+  assert_eq!(tester.float_count, 1);
+}

schala-lang/language/src/ast/walker.rs

@@ -0,0 +1,269 @@
+#![allow(dead_code)]
+use std::rc::Rc;
+use crate::ast::*;
+use crate::ast::visitor::ASTVisitor;
+use crate::util::deref_optional_box;
+
+pub fn walk_ast<V: ASTVisitor>(v: &mut V, ast: &AST) {
+  v.ast(ast);
+  walk_block(v, &ast.statements);
+}
+
+fn walk_block<V: ASTVisitor>(v: &mut V, block: &Vec<Statement>) {
+  for s in block {
+    v.statement(s);
+    statement(v, s);
+  }
+}
+
+fn statement<V: ASTVisitor>(v: &mut V, statement: &Statement) {
+  use StatementKind::*;
+  match statement.kind {
+    Expression(ref expr) => {
+      v.expression(expr);
+      expression(v, expr);
+    },
+    Declaration(ref decl) => {
+      v.declaration(decl);
+      declaration(v, decl);
+    },
+    Import(ref import_spec) => v.import(import_spec),
+    Module(ref module_spec) => {
+      v.module(module_spec);
+      walk_block(v, &module_spec.contents);
+    }
+  }
+}
+
+fn declaration<V: ASTVisitor>(v: &mut V, decl: &Declaration) {
+  use Declaration::*;
+  match decl {
+    FuncSig(sig) => {
+      v.signature(&sig);
+      signature(v, &sig);
+    },
+    FuncDecl(sig, block) => {
+      v.signature(&sig);
+      v.block(&block);
+      walk_block(v, block);
+    },
+    TypeDecl { name, body, mutable  } => v.type_declaration(name, body, *mutable),
+    TypeAlias { alias, original} => v.type_alias(alias, original), 
+    Binding { name, constant, type_anno, expr } => {
+      v.binding(name, *constant, type_anno.as_ref(), expr);
+      v.type_annotation(type_anno.as_ref());
+      v.expression(&expr);
+      expression(v, &expr);
+    },
+    Impl { type_name, interface_name, block } => {
+      v.implemention(type_name, interface_name.as_ref(), block);
+    }
+    Interface { name, signatures } => v.interface(name, signatures),
+  }
+}
+
+fn signature<V: ASTVisitor>(v: &mut V, signature: &Signature) {
+  for p in signature.params.iter() {
+    v.formal_param(p);
+  }
+  v.type_annotation(signature.type_anno.as_ref());
+  for p in signature.params.iter() {
+    formal_param(v, p);
+  }
+}
+
+fn expression<V: ASTVisitor>(v: &mut V, expression: &Expression) {
+  v.expression_kind(&expression.kind);
+  v.type_annotation(expression.type_anno.as_ref());
+  expression_kind(v, &expression.kind);
+}
+
+
+fn call<V: ASTVisitor>(v: &mut V, f: &Expression, args: &Vec<InvocationArgument>) {
+  v.expression(f);
+  expression(v, f);
+  for arg in args.iter() {
+    v.invocation_argument(arg);
+    invocation_argument(v, arg);
+  }
+}
+
+fn invocation_argument<V: ASTVisitor>(v: &mut V, arg: &InvocationArgument) {
+  use InvocationArgument::*;
+  match arg {
+    Positional(expr) => {
+      v.expression(expr);
+      expression(v, expr);
+    },
+    Keyword { expr, .. } => {
+      v.expression(expr);
+      expression(v, expr);
+    },
+    Ignored => (),
+  }
+}
+
+fn index<V: ASTVisitor>(v: &mut V, indexee: &Expression, indexers: &Vec<Expression>) {
+  v.expression(indexee);
+  for i in indexers.iter() {
+    v.expression(i);
+  }
+}
+
+fn named_struct<V: ASTVisitor>(v: &mut V, n: &QualifiedName, fields: &Vec<(Rc<String>, Expression)>) {
+  v.qualified_name(n);
+  for (_, expr) in fields.iter() {
+    v.expression(expr);
+  }
+}
+
+fn lambda<V: ASTVisitor>(v: &mut V, params: &Vec<FormalParam>, type_anno: Option<&TypeIdentifier>, body: &Block) {
+  for param in params {
+    v.formal_param(param);
+    formal_param(v, param);
+  }
+  v.type_annotation(type_anno);
+  v.block(body);
+  walk_block(v, body);
+}
+
+fn formal_param<V: ASTVisitor>(v: &mut V, param: &FormalParam) {
+  param.default.as_ref().map(|p| {
+    v.expression(p);
+    expression(v, p);
+  });
+  v.type_annotation(param.anno.as_ref());
+}
+
+fn expression_kind<V: ASTVisitor>(v: &mut V, expression_kind: &ExpressionKind) {
+  use ExpressionKind::*;
+  match expression_kind {
+    NatLiteral(n) => v.nat_literal(*n),
+    FloatLiteral(f) => v.float_literal(*f),
+    StringLiteral(s) => v.string_literal(s),
+    BoolLiteral(b) => v.bool_literal(*b),
+    BinExp(op, lhs, rhs) => {
+      v.binexp(op, lhs, rhs);
+      expression(v, lhs);
+      expression(v, rhs);
+    },
+    PrefixExp(op, arg) => {
+      v.prefix_exp(op, arg);
+      expression(v, arg);
+    }
+    TupleLiteral(exprs) => {
+      for expr in exprs {
+        v.expression(expr);
+        expression(v, expr);
+      }
+    },
+    Value(name) => v.qualified_name(name),
+    NamedStruct { name, fields } => {
+      v.named_struct(name, fields);
+      named_struct(v, name, fields);
+    }
+    Call { f, arguments } => {
+      v.call(f, arguments);
+      call(v, f, arguments);
+    },
+    Index { indexee, indexers } => {
+      v.index(indexee, indexers);
+      index(v, indexee, indexers);
+    },
+    IfExpression { discriminator, body } => {
+      v.if_expression(deref_optional_box(discriminator), body);
+      discriminator.as_ref().map(|d| expression(v, d));
+      if_expression_body(v, body);
+    },
+    WhileExpression { condition, body } => v.while_expression(deref_optional_box(condition), body),
+    ForExpression { enumerators, body } => v.for_expression(enumerators, body),
+    Lambda { params , type_anno, body } => {
+      v.lambda(params, type_anno.as_ref(), body);
+      lambda(v, params, type_anno.as_ref(), body);
+    },
+    ListLiteral(exprs) => {
+      for expr in exprs {
+        v.expression(expr);
+        expression(v, expr);
+      }
+    },
+  }
+}
+
+fn if_expression_body<V: ASTVisitor>(v: &mut V, body: &IfExpressionBody) {
+  use IfExpressionBody::*;
+  match body {
+    SimpleConditional { then_case, else_case } => {
+      walk_block(v, then_case);
+      else_case.as_ref().map(|block| walk_block(v, block));
+    },
+    SimplePatternMatch { pattern, then_case, else_case } => {
+      v.pattern(pattern);
+      walk_pattern(v, pattern);
+      walk_block(v, then_case);
+      else_case.as_ref().map(|block| walk_block(v, block));
+    },
+    CondList(arms) => {
+      for arm in arms {
+        v.condition_arm(arm);
+        condition_arm(v, arm);
+      }
+    }
+  }
+}
+
+fn condition_arm<V: ASTVisitor>(v: &mut V, arm: &ConditionArm) {
+  use Condition::*;
+  v.condition_arm(arm);
+  match arm.condition {
+    Pattern(ref pat) => {
+      v.pattern(pat);
+      walk_pattern(v, pat);
+    },
+    TruncatedOp(ref _binop, ref expr) => {
+      v.expression(expr);
+      expression(v, expr);
+    },
+    Expression(ref expr) => {
+      v.expression(expr);
+      expression(v, expr);
+    },
+    _ => ()
+  }
+  arm.guard.as_ref().map(|guard| {
+    v.expression(guard);
+    expression(v, guard);
+  });
+  v.block(&arm.body);
+  walk_block(v, &arm.body);
+}
+
+fn walk_pattern<V: ASTVisitor>(v: &mut V, pat: &Pattern) {
+  use Pattern::*;
+  match pat {
+    TuplePattern(patterns) => {
+      for pat in patterns {
+        v.pattern(pat);
+        walk_pattern(v, pat);
+      }
+    },
+    TupleStruct(qualified_name, patterns) => {
+      v.qualified_name(qualified_name);
+      for pat in patterns {
+        v.pattern(pat);
+        walk_pattern(v, pat);
+      }
+    },
+    Record(qualified_name, name_and_patterns) => {
+      v.qualified_name(qualified_name);
+      for (_, pat) in name_and_patterns {
+        v.pattern(pat);
+        walk_pattern(v, pat);
+      }
+    },
+    VarOrName(qualified_name) => {
+      v.qualified_name(qualified_name);
+    },
+    _ => ()
+  }
+}

schala-lang/language/src/eval.rs

@@ -1,27 +1,25 @@
-
-use std::cell::RefCell;
 use std::rc::Rc;
 use std::fmt::Write;
 use std::io;
 
 use itertools::Itertools;
 
+use crate::schala::SymbolTableHandle;
 use crate::util::ScopeStack;
 use crate::reduced_ast::{BoundVars, ReducedAST, Stmt, Expr, Lit, Func, Alternative, Subpattern};
-use crate::symbol_table::{SymbolSpec, Symbol, SymbolTable, ScopeSegment, ScopeSegmentKind, FullyQualifiedSymbolName};
+use crate::symbol_table::{SymbolSpec, Symbol, SymbolTable, FullyQualifiedSymbolName};
 use crate::builtin::Builtin;
 
 mod test;
 
 pub struct State<'a> {
   values: ScopeStack<'a, Rc<String>, ValueEntry>,
-  symbol_table_handle: Rc<RefCell<SymbolTable>>,
 }
 
 impl<'a> State<'a> {
-  pub fn new(symbol_table_handle: Rc<RefCell<SymbolTable>>) -> State<'a> {
+  pub fn new() -> State<'a> {
     let values = ScopeStack::new(Some(format!("global")));
-    State { values, symbol_table_handle }
+    State { values }
   }
 
   pub fn debug_print(&self) -> String {
@@ -31,7 +29,6 @@ impl<'a> State<'a> {
   fn new_frame(&'a self, items: &'a Vec<Node>, bound_vars: &BoundVars) -> State<'a> {
     let mut inner_state = State {
       values: self.values.new_scope(None),
-      symbol_table_handle: self.symbol_table_handle.clone(),
     };
     for (bound_var, val) in bound_vars.iter().zip(items.iter()) {
       if let Some(bv) = bound_var.as_ref() {
@@ -70,12 +67,12 @@ fn paren_wrapped_vec(terms: impl Iterator<Item=String>) -> String {
 
 
 impl Node {
-  fn to_repl(&self, symbol_table: &SymbolTable) -> String {
+  fn to_repl(&self) -> String {
     match self {
-      Node::Expr(e) => e.to_repl(symbol_table),
+      Node::Expr(e) => e.to_repl(),
       Node::PrimObject { name, items, .. } if items.len() == 0 => format!("{}", name),
-      Node::PrimObject { name, items, .. } => format!("{}{}", name, paren_wrapped_vec(items.iter().map(|x| x.to_repl(symbol_table)))),
-      Node::PrimTuple { items } => format!("{}", paren_wrapped_vec(items.iter().map(|x| x.to_repl(symbol_table)))),
+      Node::PrimObject { name, items, .. } => format!("{}{}", name, paren_wrapped_vec(items.iter().map(|x| x.to_repl()))),
+      Node::PrimTuple { items } => format!("{}", paren_wrapped_vec(items.iter().map(|x| x.to_repl()))),
     }
   }
   fn is_true(&self) -> bool {
@@ -100,12 +97,10 @@ impl Expr {
   fn to_node(self) -> Node {
     Node::Expr(self)
   }
-  fn to_repl(&self, symbol_table: &SymbolTable) -> String {
+  fn to_repl(&self) -> String {
     use self::Lit::*;
     use self::Func::*;
 
-    let _ = symbol_table;
-
     match self {
       Expr::Lit(ref l) => match l {
         Nat(n) => format!("{}", n),
@@ -122,7 +117,7 @@ impl Expr {
       Expr::Constructor { type_name, arity, .. } => {
         format!("<constructor for `{}` arity {}>", type_name, arity)
       },
-      Expr::Tuple(exprs) => paren_wrapped_vec(exprs.iter().map(|x| x.to_repl(symbol_table))),
+      Expr::Tuple(exprs) => paren_wrapped_vec(exprs.iter().map(|x| x.to_repl())),
       _ => format!("{:?}", self),
     }
   }
@@ -157,8 +152,7 @@ impl<'a> State<'a> {
     for statement in ast.0 {
       match self.statement(statement) {
         Ok(Some(ref output)) if repl => {
-          let ref symbol_table = self.symbol_table_handle.borrow();
-          acc.push(Ok(output.to_repl(symbol_table)))
+          acc.push(Ok(output.to_repl()))
         },
         Ok(_) => (),
         Err(error) => {
@@ -212,7 +206,10 @@ impl<'a> State<'a> {
       Node::Expr(expr) => match expr {
         literal @ Lit(_) => Ok(Node::Expr(literal)),
         Call { box f, args } => self.call_expression(f, args),
-        Sym(v) => self.handle_sym(v),
+        Sym(name) => Ok(match self.values.lookup(&name) {
+          Some(ValueEntry::Binding { val, .. }) => val.clone(),
+          None => return Err(format!("Could not look up symbol {}", name))
+        }),
         Constructor { arity, ref name, tag, .. } if arity == 0 => Ok(Node::PrimObject { name: name.clone(), tag, items: vec![] }),
         constructor @ Constructor { .. } => Ok(Node::Expr(constructor)),
         func @ Func(_) => Ok(Node::Expr(func)),
@@ -264,7 +261,6 @@ impl<'a> State<'a> {
         }
         let mut func_state = State {
           values: self.values.new_scope(name.map(|n| format!("{}", n))),
-          symbol_table_handle: self.symbol_table_handle.clone(),
         };
         for (param, val) in params.into_iter().zip(args.into_iter()) {
           let val = func_state.expression(Node::Expr(val))?;
@@ -343,13 +339,11 @@ impl<'a> State<'a> {
 
       /* builtin functions */
       (IOPrint, &[ref anything]) => {
-        let ref symbol_table = self.symbol_table_handle.borrow();
-        print!("{}", anything.to_repl(symbol_table));
+        print!("{}", anything.to_repl());
         Expr::Unit.to_node()
       },
       (IOPrintLn, &[ref anything]) => {
-        let ref symbol_table = self.symbol_table_handle.borrow();
-        println!("{}", anything.to_repl(symbol_table));
+        println!("{}", anything.to_repl());
         Expr::Unit.to_node()
       },
       (IOGetLine, &[]) => {
@@ -458,45 +452,4 @@ impl<'a> State<'a> {
     }
     Err(format!("{:?} failed pattern match", cond))
   }
-
-  //TODO if I don't need to lookup by name here...
-  fn handle_sym(&mut self, name: Rc<String>) -> EvalResult<Node> {
-    use self::ValueEntry::*;
-    use self::Func::*;
-    //TODO add a layer of indirection here to talk to the symbol table first, and only then look up
-    //in the values table
-
-    let symbol_table = self.symbol_table_handle.borrow();
-    let value = symbol_table.lookup_by_fqsn(&fqsn!(name ; tr));
-    Ok(match value {
-      Some(Symbol { name, spec, .. }) => match spec {
-        //TODO I'll need this type_name later to do a table lookup
-        SymbolSpec::DataConstructor { type_name: _type_name, type_args, .. } => {
-          if type_args.len() == 0 {
-            Node::PrimObject { name: name.clone(), tag: 0, items: vec![] }
-          } else {
-            return Err(format!("This data constructor thing not done"))
-          }
-        },
-        SymbolSpec::Func(_) => match self.values.lookup(&name) {
-          Some(Binding { val: Node::Expr(Expr::Func(UserDefined { name, params, body })), .. }) => {
-            Node::Expr(Expr::Func(UserDefined { name: name.clone(), params: params.clone(), body: body.clone() }))
-          },
-          _ => unreachable!(),
-        },
-        SymbolSpec::RecordConstructor { .. } => return Err(format!("This shouldn't be a record!")),
-        SymbolSpec::Binding => match self.values.lookup(&name) {
-          Some(Binding { val, .. }) => val.clone(),
-          None => return Err(format!("Symbol {} exists in symbol table but not in evaluator table", name))
-        }
-      },
-      //TODO ideally this should be returning a runtime error if this is ever None, but it's not
-      //handling all bindings correctly yet
-      //None => return Err(format!("Couldn't find value {}", name)),
-      None => match self.values.lookup(&name) {
-        Some(Binding { val, .. }) => val.clone(),
-        None => return Err(format!("Couldn't find value {}", name)),
-      }
-    })
-  }
 }

schala-lang/language/src/eval/test.rs

@@ -9,17 +9,17 @@ use crate::reduced_ast::reduce;
 use crate::eval::State;
 
 fn evaluate_all_outputs(input: &str) -> Vec<Result<String, String>> {
-  let symbol_table = Rc::new(RefCell::new(SymbolTable::new()));
-  let mut state = State::new(symbol_table);
-  let mut ast = crate::util::quick_ast(input);
-  state.symbol_table_handle.borrow_mut().add_top_level_symbols(&ast).unwrap();
+  let (mut ast, source_map) = crate::util::quick_ast(input);
+  let source_map = Rc::new(RefCell::new(source_map));
+  let symbol_table = Rc::new(RefCell::new(SymbolTable::new(source_map)));
+  symbol_table.borrow_mut().add_top_level_symbols(&ast).unwrap();
   {
-  let mut t = &mut state.symbol_table_handle.borrow_mut();
-  let mut scope_resolver = crate::scope_resolution::ScopeResolver::new(&mut t);
+  let mut scope_resolver = ScopeResolver::new(symbol_table.clone());
   let _ = scope_resolver.resolve(&mut ast);
   }
 
-  let reduced = reduce(&ast, &state.symbol_table_handle.borrow());
+  let reduced = reduce(&ast, &symbol_table.borrow());
+  let mut state = State::new();
   let all_output = state.evaluate(reduced, true);
   all_output
 }
@@ -69,7 +69,7 @@ fn scopes() {
     test_in_fresh_env!(scope_ok, "10");
     let scope_ok = r#"
     let a = 20
-    fn haha() {
+    fn queque() {
       let a = 10
       a
     }
@@ -96,26 +96,26 @@ fn full_if_matching() {
   let source = r#"
 type Option<T> = Some(T) | None
 let a = Option::None
-if a { is Option::None -> 4, is Option::Some(x) -> x }
+if a { is Option::None then 4, is Option::Some(x) then x }
 "#;
 test_in_fresh_env!(source, "4");
 
 let source = r#"
 type Option<T> = Some(T) | None
 let a = Option::Some(99)
-if a { is Option::None -> 4, is Option::Some(x) -> x }
+if a { is Option::None then 4, is Option::Some(x) then x }
 "#;
 test_in_fresh_env!(source, "99");
 
 let source = r#"
 let a = 10
-if a { is 10 -> "x", is 4 -> "y" }
+if a { is 10 then "x", is 4 then "y" }
 "#;
 test_in_fresh_env!(source, "\"x\"");
 
 let source = r#"
 let a = 10
-if a { is 15 -> "x", is 10 -> "y" }
+if a { is 15 then "x", is 10 then "y" }
 "#;
 test_in_fresh_env!(source, "\"y\"");
 }
@@ -124,7 +124,7 @@ test_in_fresh_env!(source, "\"y\"");
 fn string_pattern() {
   let source = r#"
 let a = "foo"
-if a { is "foo" -> "x", is _ -> "y" }
+if a { is "foo" then "x", is _ then "y" }
 "#;
 test_in_fresh_env!(source, "\"x\"");
 }
@@ -134,8 +134,8 @@ fn boolean_pattern() {
   let source = r#"
 let a = true
 if a {
-  is true -> "x",
-  is false -> "y"
+  is true then "x",
+  is false then "y"
 }
 "#;
 test_in_fresh_env!(source, "\"x\"");
@@ -145,7 +145,7 @@ test_in_fresh_env!(source, "\"x\"");
 fn boolean_pattern_2() {
   let source = r#"
 let a = false
-if a { is true -> "x", is false -> "y" }
+if a { is true then "x", is false then "y" }
 "#;
 test_in_fresh_env!(source, "\"y\"");
 }
@@ -155,7 +155,7 @@ fn ignore_pattern() {
   let source = r#"
 type Option<T> = Some(T) | None
 if Option::Some(10) {
-  is _ -> "hella"
+  is _ then "hella"
 }
 "#;
 test_in_fresh_env!(source, "\"hella\"");
@@ -165,8 +165,8 @@ test_in_fresh_env!(source, "\"hella\"");
 fn tuple_pattern() {
   let source = r#"
 if (1, 2) {
-  is (1, x) -> x,
-  is _ -> 99
+  is (1, x) then x,
+  is _ then 99
 }
 "#;
 test_in_fresh_env!(source, 2);
@@ -177,8 +177,8 @@ test_in_fresh_env!(source, 2);
 fn tuple_pattern_2() {
   let source = r#"
 if (1, 2) {
-  is (10, x) -> x,
-  is (y, x) -> x + y
+  is (10, x) then x,
+  is (y, x) then x + y
 }
 "#;
 test_in_fresh_env!(source, 3);
@@ -188,8 +188,8 @@ test_in_fresh_env!(source, 3);
 fn tuple_pattern_3() {
   let source = r#"
 if (1, 5) {
-  is (10, x) -> x,
-  is (1, x) -> x
+  is (10, x) then x,
+  is (1, x) then x
 }
 "#;
 test_in_fresh_env!(source, 5);
@@ -199,8 +199,8 @@ test_in_fresh_env!(source, 5);
 fn tuple_pattern_4() {
   let source = r#"
 if (1, 5) {
-  is (10, x) -> x,
-  is (1, x) -> x,
+  is (10, x) then x,
+  is (1, x) then x,
 }
 "#;
 test_in_fresh_env!(source, 5);
@@ -215,21 +215,21 @@ let b = Stuff::Jugs(1, "haha")
 let c = Stuff::Mardok
 
 let x = if a {
-  is Stuff::Mulch(20) -> "x",
-  is _ -> "ERR"
+  is Stuff::Mulch(20) then "x",
+  is _ then "ERR"
 }
 
 let y = if b {
-  is Stuff::Mulch(n) -> "ERR",
-  is Stuff::Jugs(2, _) -> "ERR",
-  is Stuff::Jugs(1, s) -> s,
-  is _ -> "ERR",
+  is Stuff::Mulch(n) then "ERR",
+  is Stuff::Jugs(2, _) then "ERR",
+  is Stuff::Jugs(1, s) then s,
+  is _ then "ERR",
 }
 
 let z = if c {
-  is Stuff::Jugs(_, _) -> "ERR",
-  is Stuff::Mardok -> "NIGH",
-  is _ -> "ERR",
+  is Stuff::Jugs(_, _) then "ERR",
+  is Stuff::Mardok then "NIGH",
+  is _ then "ERR",
 }
 
 (x, y, z)
@@ -258,3 +258,12 @@ milta()(10)
   "#;
   test_in_fresh_env!(source, "43");
   }
+
+#[test]
+fn import_all() {
+  let source = r#"
+type Option<T> = Some(T) | None
+import Option::*
+let x = Some(9); if x is Some(q) then { q } else { 0 }"#;
+  test_in_fresh_env!(source, "9");
+}

schala-lang/language/src/lib.rs

@@ -1,5 +1,4 @@
 #![feature(trace_macros)]
-#![feature(custom_attribute)]
 //#![feature(unrestricted_attribute_tokens)]
 #![feature(slice_patterns, box_patterns, box_syntax)]
 
@@ -17,6 +16,8 @@ extern crate schala_repl;
 extern crate schala_lang_codegen;
 extern crate ena;
 extern crate derivative;
+extern crate colored;
+extern crate radix_trie;
 
 
 macro_rules! bx {
@@ -38,6 +39,7 @@ mod scope_resolution;
 mod builtin;
 mod reduced_ast;
 mod eval;
+mod source_map;
 
 mod schala;
 

schala-lang/language/src/parsing.rs

@@ -13,7 +13,7 @@
 //! ```text
 //! program := (statement delimiter)* EOF
 //! delimiter := NEWLINE | ";"
-//! statement := expression | declaration
+//! statement := expression | declaration | import | module
 //! block := "{" (statement delimiter)* "}"
 //! declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
 //! ```
@@ -113,19 +113,27 @@
 //! record_pattern_entry := IDENTIFIER | IDENTIFIER ":" Pattern
 //! tuple_struct_pattern := qualified_identifier "(" (pattern, ",")* ")"
 //! ```
+//! ### If expressions
+//!
+//! TODO: it would be nice if the grammar could capture an incomplete precedence expr in the
+//! discriminator
 //!
-//! ### If-expressions
 //! ```text
-//! if_expr := "if" discriminator ("then" condititional | "is" simple_pattern_match | guard_block)
-//! discriminator := precedence_expr (operator)+
-//! conditional := expr_or_block else_clause
-//! simple_pattern_match := pattern "then" conditional
-//! else_clause := ε | "else" expr_or_block
-//! guard_block := "{" (guard_arm, ",")* "}"
-//! guard_arm := guard "->" expr_or_block
-//! guard := "is" pattern | (operator)+ precedence_expr
+//! if_expr := "if" discriminator if_expr_body
+//! if_expr_body := ("then" simple_conditional | "is" simple_pattern_match | cond_block)
+//! discriminator := ε | expression
+//! simple_conditional := expr_or_block else_case
+//! simple_pattern_match := pattern "then" simple_conditional
+//! else_case := "else" expr_or_block
+//!
+//! cond_block := "{" (cond_arm comma_or_delimiter)* "}"
+//! cond_arm := condition guard "then" expr_or_block | "else" expr_or_block
+//! condition := "is" pattern | operator precedence_expr | expression
+//! guard := "if" expression
+//! comma_or_delimiter := "," | delimiter
 //! ```
 //!
+//!
 //! ### While expressions
 //! ```text
 //! while_expr := "while" while_cond "{" (statement delimiter)* "}"
@@ -141,8 +149,15 @@
 //! enumerators := enumerator ("," enumerators)*
 //! enumerator :=  identifier "<-" expression | identifier "=" expression //TODO add guards, etc.
 //! ```
+//! ## Imports
+//! ```text
+//! import := 'import' IDENTIFIER (:: IDENTIFIER)*  import_suffix
+//! import_suffix := ε | '::{' IDENTIFIER (, IDENTIFIER)* '}' | '*' //TODO add qualified, exclusions, etc.
 //!
-
+//! ## Modules
+//!
+//! module := 'module' IDENTIFIER '{' statement* '}'
+//! ```
 mod test;
 
 use std::rc::Rc;
@@ -152,18 +167,21 @@ use crate::tokenizing::*;
 use crate::tokenizing::Kw::*;
 use crate::tokenizing::TokenKind::*;
 
+use crate::source_map::Location;
 use crate::ast::*;
+use crate::schala::SourceMapHandle;
 
 /// Represents a parsing error
 #[derive(Debug)]
 pub struct ParseError {
+  pub production_name: Option<String>,
   pub msg: String,
   pub token: Token
 }
 
 impl ParseError {
   fn new_with_token<T, M>(msg: M, token: Token) -> ParseResult<T> where M: Into<String> {
-    Err(ParseError { msg: msg.into(), token })
+    Err(ParseError { msg: msg.into(), token, production_name: None })
   }
 }
 
@@ -184,8 +202,10 @@ pub struct Parser {
   parse_level: u32,
   restrictions: ParserRestrictions,
   id_store: ItemIdStore,
+  source_map: SourceMapHandle
 }
 
+
 struct ParserRestrictions {
   no_struct_literal: bool
 }
@@ -193,14 +213,14 @@ struct ParserRestrictions {
 struct TokenHandler {
   tokens: Vec<Token>,
   idx: usize,
-  end_of_file: (usize, usize),
+  end_of_file: Location
 }
 
 impl TokenHandler {
   fn new(tokens: Vec<Token>) -> TokenHandler {
     let end_of_file = match tokens.last() {
-      None => (0, 0),
-      Some(t) => (t.line_num, t.char_num)
+      None => Location { line_num: 0, char_num : 0 },
+      Some(t) => t.location,
     };
     TokenHandler { idx: 0, tokens, end_of_file }
   }
@@ -213,49 +233,56 @@ impl TokenHandler {
     self.peek_n(n).kind
   }
   fn peek(&mut self) -> Token {
-    self.tokens.get(self.idx).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, line_num: self.end_of_file.0, char_num: self.end_of_file.1})
+    self.tokens.get(self.idx).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
   }
   /// calling peek_n(0) is the same thing as peek()
   fn peek_n(&mut self, n: usize) -> Token {
-    self.tokens.get(self.idx + n).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, line_num: self.end_of_file.0, char_num: self.end_of_file.1})
+    self.tokens.get(self.idx + n).map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
   }
   fn next(&mut self) -> Token {
     self.idx += 1;
-    self.tokens.get(self.idx - 1).map(|t: &Token| { t.clone() }).unwrap_or(Token { kind: TokenKind::EOF, line_num: self.end_of_file.0, char_num: self.end_of_file.1})
+    self.tokens.get(self.idx - 1).map(|t: &Token| { t.clone() }).unwrap_or(Token { kind: TokenKind::EOF, location: self.end_of_file })
   }
 }
 
 impl Parser {
   /// Create a new parser initialized with some tokens.
-  pub fn new(initial_input: Vec<Token>) -> Parser {
+  pub fn new(source_map: SourceMapHandle) -> Parser {
     Parser {
-      token_handler: TokenHandler::new(initial_input),
+      token_handler: TokenHandler::new(vec![]),
       parse_record: vec![],
       parse_level: 0,
       restrictions: ParserRestrictions { no_struct_literal: false },
       id_store: ItemIdStore::new(),
+      source_map,
     }
   }
 
+  pub fn add_new_tokens(&mut self, new_tokens: Vec<Token>) {
+    self.token_handler = TokenHandler::new(new_tokens);
+  }
+
   /// Parse all loaded tokens up to this point.
   pub fn parse(&mut self) -> ParseResult<AST> {
     self.program()
   }
 
-  /*
-  pub fn parse_with_new_tokens(&mut self, new_tokens: Vec<Token>) -> ParseResult<AST> {
-
-  }
-  */
-
   pub fn format_parse_trace(&self) -> String {
     let mut buf = String::new();
+    buf.push_str("Parse productions:\n");
+    let mut next_token = None;
     for r in self.parse_record.iter() {
       let mut indent = String::new();
       for _ in 0..r.level {
-        indent.push(' ');
+        indent.push('.');
       }
-      buf.push_str(&format!("{}Production `{}`, token: {}\n", indent, r.production_name, r.next_token))
+      let effective_token = if next_token == Some(&r.next_token) {
+        "".to_string()
+      } else {
+        next_token = Some(&r.next_token);
+        format!(", next token: {}", r.next_token)
+      };
+      buf.push_str(&format!("{}`{}`{}\n", indent, r.production_name, effective_token));
     }
     buf
   }
@@ -343,15 +370,20 @@ impl Parser {
   #[recursive_descent_method]
   fn statement(&mut self) -> ParseResult<Statement> {
     //TODO handle error recovery here
-    let kind = match self.token_handler.peek().get_kind() {
+    let tok = self.token_handler.peek();
+    let kind = match tok.get_kind() {
       Keyword(Type) => self.type_declaration().map(|decl| { StatementKind::Declaration(decl) }),
       Keyword(Func)=> self.func_declaration().map(|func| { StatementKind::Declaration(func) }),
       Keyword(Let) => self.binding_declaration().map(|decl| StatementKind::Declaration(decl)),
       Keyword(Interface) => self.interface_declaration().map(|decl| StatementKind::Declaration(decl)),
       Keyword(Impl) => self.impl_declaration().map(|decl| StatementKind::Declaration(decl)),
-      _ => self.expression().map(|expr| { StatementKind::Expression(expr.into()) } ),
+      Keyword(Import) => self.import_declaration().map(|spec| StatementKind::Import(spec)),
+      Keyword(Module) => self.module_declaration().map(|spec| StatementKind::Module(spec)),
+      _ => self.expression().map(|expr| { StatementKind::Expression(expr) } ),
     }?;
-    Ok(Statement { kind, id: self.id_store.fresh() })
+    let id = self.id_store.fresh();
+    self.source_map.borrow_mut().add_location(&id, tok.location); 
+    Ok(Statement { kind, id })
   }
 
   #[recursive_descent_method]
@@ -384,7 +416,7 @@ impl Parser {
     let alias = self.identifier()?;
     expect!(self, Equals);
     let original = self.identifier()?;
-    Ok(Declaration::TypeAlias(alias, original))
+    Ok(Declaration::TypeAlias { alias, original })
   }
 
   #[recursive_descent_method]
@@ -469,7 +501,6 @@ impl Parser {
     Ok(delimited!(self, LParen, formal_param, Comma, RParen))
   }
 
-  //TODO needs to support default values
   #[recursive_descent_method]
   fn formal_param(&mut self) -> ParseResult<FormalParam> {
     let name = self.identifier()?;
@@ -480,7 +511,7 @@ impl Parser {
     let default = match self.token_handler.peek_kind() {
       Equals => {
         self.token_handler.next();
-        Some(self.expression()?.into())
+        Some(self.expression()?)
       },
       _ => None
     };
@@ -505,7 +536,7 @@ impl Parser {
     };
 
     expect!(self, Equals);
-    let expr = self.expression()?.into();
+    let expr = self.expression()?;
 
     Ok(Declaration::Binding { name, constant, type_anno, expr })
   }
@@ -611,10 +642,11 @@ impl Parser {
       let next_tok = self.token_handler.next();
       let operation = match BinOp::from_sigil_token(&next_tok.kind) {
         Some(sigil) => sigil,
+        //TODO I think I can fix this unreachable
         None => unreachable!()
       };
       let rhs = self.precedence_expr(new_precedence)?;
-      lhs = Expression::new(self.id_store.fresh(), ExpressionKind::BinExp(operation, bx!(lhs.into()), bx!(rhs.into())));
+      lhs = Expression::new(self.id_store.fresh(), ExpressionKind::BinExp(operation, bx!(lhs), bx!(rhs)));
     }
     self.parse_level -= 1;
     Ok(lhs)
@@ -632,7 +664,7 @@ impl Parser {
         let prefix_op = PrefixOp::from_str(sigil.as_str()).unwrap();
         Ok(Expression::new(
           self.id_store.fresh(),
-          ExpressionKind::PrefixExp(prefix_op, bx!(expr.into()))
+          ExpressionKind::PrefixExp(prefix_op, bx!(expr))
         ))
       },
       _ => self.call_expr()
@@ -644,8 +676,7 @@ impl Parser {
     let mut expr = self.index_expr()?;
     while let LParen = self.token_handler.peek_kind() {
       let arguments = delimited!(self, LParen, invocation_argument, Comma, RParen);
-      let arguments = arguments.into_iter().collect();
-      expr = Expression::new(self.id_store.fresh(), ExpressionKind::Call { f: bx!(expr.into()), arguments }); //TODO no type anno is incorrect
+      expr = Expression::new(self.id_store.fresh(), ExpressionKind::Call { f: bx!(expr), arguments }); //TODO no type anno is incorrect
     }
 
     Ok(expr)
@@ -663,16 +694,16 @@ impl Parser {
           Equals => {
             self.token_handler.next();
             self.token_handler.next();
-            let expr = self.expression()?.into();
+            let expr = self.expression()?;
             InvocationArgument::Keyword { name: s.clone(), expr }
           },
           _ => {
             let expr = self.expression()?;
-            InvocationArgument::Positional(expr.into())
+            InvocationArgument::Positional(expr)
           }
         }
       },
-      _ => InvocationArgument::Positional(self.expression()?.into())
+      _ => InvocationArgument::Positional(self.expression()?)
     })
   }
 
@@ -680,10 +711,9 @@ impl Parser {
   fn index_expr(&mut self) -> ParseResult<Expression> {
     let primary = self.primary()?;
     Ok(if let LSquareBracket = self.token_handler.peek_kind() {
-      let indexers = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket)
-        .into_iter().map(|ex| ex.into()).collect();
+      let indexers = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket);
       Expression::new(self.id_store.fresh(), ExpressionKind::Index {
-        indexee: bx!(Expression::new(self.id_store.fresh(), primary.kind).into()),
+        indexee: bx!(Expression::new(self.id_store.fresh(), primary.kind)),
         indexers,
       })
     } else {
@@ -708,8 +738,7 @@ impl Parser {
 
   #[recursive_descent_method]
   fn list_expr(&mut self) -> ParseResult<Expression> {
-    let exprs = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket)
-      .into_iter().map(|ex| ex.into()).collect();
+    let exprs = delimited!(self, LSquareBracket, expression, Comma, RSquareBracket);
     Ok(Expression::new(self.id_store.fresh(), ExpressionKind::ListLiteral(exprs)))
   }
 
@@ -750,10 +779,7 @@ impl Parser {
       match inner.len() {
         0 => Ok(Expression::new(self.id_store.fresh(), TupleLiteral(vec![]))),
         1 => Ok(inner.pop().unwrap()),
-        _ => {
-          let inner: Vec<Expression> = inner.into_iter().map(|ex| ex.into()).collect();
-          Ok(Expression::new(self.id_store.fresh(), TupleLiteral(inner)))
-        }
+        _ => Ok(Expression::new(self.id_store.fresh(), TupleLiteral(inner)))
       }
     };
     self.restrictions.no_struct_literal = old_struct_value;
@@ -763,7 +789,8 @@ impl Parser {
   #[recursive_descent_method]
   fn identifier_expr(&mut self) -> ParseResult<Expression> {
     use self::ExpressionKind::*;
-    let qualified_identifier = self.qualified_identifier()?;
+    let components = self.qualified_identifier()?;
+    let qualified_identifier = QualifiedName { id: self.id_store.fresh(), components };
     Ok(match self.token_handler.peek_kind() {
       LCurlyBrace if !self.restrictions.no_struct_literal => {
         let fields = self.record_block()?;
@@ -774,7 +801,7 @@ impl Parser {
   }
 
   #[recursive_descent_method]
-  fn qualified_identifier(&mut self) -> ParseResult<QualifiedName> {
+  fn qualified_identifier(&mut self) -> ParseResult<Vec<Rc<String>>> {
     let mut components = vec![self.identifier()?];
     loop {
       match (self.token_handler.peek_kind(), self.token_handler.peek_kind_n(1)) {
@@ -785,15 +812,12 @@ impl Parser {
         _ => break,
       }
     }
-    Ok(QualifiedName { id: self.id_store.fresh(), components })
+    Ok(components)
   }
 
   #[recursive_descent_method]
   fn record_block(&mut self) -> ParseResult<Vec<(Rc<String>, Expression)>> {
-    Ok(
-      delimited!(self, LCurlyBrace, record_entry, Comma, RCurlyBrace)
-      .into_iter().map(|(s, ex)| (s, ex.into())).collect()
-    )
+    Ok(delimited!(self, LCurlyBrace, record_entry, Comma, RCurlyBrace))
   }
 
   #[recursive_descent_method]
@@ -807,53 +831,47 @@ impl Parser {
   #[recursive_descent_method]
   fn if_expr(&mut self) -> ParseResult<Expression> {
     expect!(self, Keyword(Kw::If));
-    let discriminator = Box::new({
-      self.restrictions.no_struct_literal = true;
-      let x = self.discriminator();
-      self.restrictions.no_struct_literal = false;
-      x?
-    });
-
-    let body = Box::new(match self.token_handler.peek_kind() {
-      Keyword(Kw::Then) => self.conditional()?,
-      Keyword(Kw::Is) => self.simple_pattern_match()? ,
-      _ => self.guard_block()?
-    });
-
+    let old_struct_value = self.restrictions.no_struct_literal;
+    self.restrictions.no_struct_literal = true;
+    let discriminator = if let LCurlyBrace = self.token_handler.peek_kind() {
+      None
+    } else {
+      Some(Box::new(self.expression()?))
+    };
+    let body = Box::new(self.if_expr_body()?);
+    self.restrictions.no_struct_literal = old_struct_value;
     Ok(Expression::new(self.id_store.fresh(), ExpressionKind::IfExpression { discriminator, body }))
   }
 
   #[recursive_descent_method]
-  fn discriminator(&mut self) -> ParseResult<Discriminator> {
-    let lhs = self.prefix_expr()?;
-    let ref next = self.token_handler.peek_kind();
-    Ok(if let Some(op) = BinOp::from_sigil_token(next) {
-      Discriminator::BinOp(lhs.into(), op)
-    } else {
-      Discriminator::Simple(lhs.into())
-    })
+  fn if_expr_body(&mut self) -> ParseResult<IfExpressionBody> {
+    match self.token_handler.peek_kind() {
+      Keyword(Kw::Then) => self.simple_conditional(),
+      Keyword(Kw::Is) => self.simple_pattern_match(),
+      _ => self.cond_block(),
+    }
   }
 
   #[recursive_descent_method]
-  fn conditional(&mut self) -> ParseResult<IfExpressionBody> {
+  fn simple_conditional(&mut self) -> ParseResult<IfExpressionBody> {
     expect!(self, Keyword(Kw::Then));
-    let then_clause = self.expr_or_block()?;
-    let else_clause = self.else_clause()?;
-    Ok(IfExpressionBody::SimpleConditional(then_clause, else_clause))
+    let then_case = self.expr_or_block()?;
+    let else_case = self.else_case()?;
+    Ok(IfExpressionBody::SimpleConditional {then_case, else_case })
   }
 
   #[recursive_descent_method]
   fn simple_pattern_match(&mut self) -> ParseResult<IfExpressionBody> {
     expect!(self, Keyword(Kw::Is));
-    let pat = self.pattern()?;
+    let pattern = self.pattern()?;
     expect!(self, Keyword(Kw::Then));
-    let then_clause = self.expr_or_block()?;
-    let else_clause = self.else_clause()?;
-    Ok(IfExpressionBody::SimplePatternMatch(pat, then_clause, else_clause))
+    let then_case = self.expr_or_block()?;
+    let else_case = self.else_case()?;
+    Ok(IfExpressionBody::SimplePatternMatch { pattern, then_case, else_case })
   }
 
   #[recursive_descent_method]
-  fn else_clause(&mut self) -> ParseResult<Option<Block>> {
+  fn else_case(&mut self) -> ParseResult<Option<Block>> {
     Ok(if let Keyword(Kw::Else) = self.token_handler.peek_kind() {
       self.token_handler.next();
       Some(self.expr_or_block()?)
@@ -863,63 +881,67 @@ impl Parser {
   }
 
   #[recursive_descent_method]
-  fn guard_block(&mut self) -> ParseResult<IfExpressionBody> {
-    //TODO - delimited! isn't sophisticated enough to do thisa
-    //let guards = delimited!(self, LCurlyBrace, guard_arm, Comma, RCurlyBrace);
+  fn cond_block(&mut self) -> ParseResult<IfExpressionBody> {
     expect!(self, LCurlyBrace);
-
-    let mut guards = vec![];
+    let mut cond_arms = vec![];
     loop {
       match self.token_handler.peek_kind() {
         RCurlyBrace | EOF => break,
         Semicolon | Newline => { self.token_handler.next(); continue},
         _ => {
-          let guard_arm = self.guard_arm()?;
-          guards.push(guard_arm);
-          loop {
-            match self.token_handler.peek_kind() {
-              Semicolon | Newline => { self.token_handler.next(); continue; },
-              _ => break,
-            }
+          cond_arms.push(self.cond_arm()?);
+          match self.token_handler.peek_kind() {
+            Comma | Semicolon | Newline => { self.token_handler.next(); continue; },
+            _ => break,
           }
-          if let RCurlyBrace = self.token_handler.peek_kind() {
-            break;
-          }
-          expect!(self, Comma);
         }
       }
     }
     expect!(self, RCurlyBrace);
-    Ok(IfExpressionBody::GuardList(guards))
+    Ok(IfExpressionBody::CondList(cond_arms))
   }
 
   #[recursive_descent_method]
-  fn guard_arm(&mut self) -> ParseResult<GuardArm> {
-    let guard = self.guard()?;
-    expect!(self, Operator(ref c) if **c == "->");
+  fn cond_arm(&mut self) -> ParseResult<ConditionArm> {
+    let (condition, guard) = if let Keyword(Kw::Else) = self.token_handler.peek_kind() {
+      self.token_handler.next();
+      (Condition::Else, None)
+    } else {
+      let condition = self.condition()?;
+      let guard = self.guard()?;
+      expect!(self, Keyword(Kw::Then));
+      (condition, guard)
+    };
     let body = self.expr_or_block()?;
-    Ok(GuardArm { guard, body })
+    Ok(ConditionArm { condition, guard, body })
   }
 
   #[recursive_descent_method]
-  fn guard(&mut self) -> ParseResult<Guard> {
+  fn condition(&mut self) -> ParseResult<Condition> {
     Ok(match self.token_handler.peek_kind() {
       Keyword(Kw::Is) => {
         self.token_handler.next();
-        let pat = self.pattern()?;
-        Guard::Pat(pat)
+        Condition::Pattern(self.pattern()?)
       },
       ref tok if BinOp::from_sigil_token(tok).is_some() => {
         let op = BinOp::from_sigil_token(&self.token_handler.next().kind).unwrap();
-        let precedence = op.get_precedence();
-        let Expression { kind, .. } = self.precedence_expr(precedence)?;
-        Guard::HalfExpr(HalfExpr { op: Some(op), expr: kind })
+        let expr = self.expression()?;
+        Condition::TruncatedOp(op, expr)
       },
       _ => {
-        //TODO - I think there's a better way to do this involving the precedence of ->
-        let Expression { kind, .. } = self.prefix_expr()?;
-        Guard::HalfExpr(HalfExpr { op: None, expr: kind })
-      }
+        Condition::Expression(self.expression()?)
+      },
+    })
+  }
+
+  #[recursive_descent_method]
+  fn guard(&mut self) -> ParseResult<Option<Expression>> {
+    Ok(match self.token_handler.peek_kind() {
+      Keyword(Kw::If) => {
+        self.token_handler.next();
+        Some(self.expression()?)
+      },
+      _ => None
     })
   }
 
@@ -937,18 +959,19 @@ impl Parser {
   fn simple_pattern(&mut self) -> ParseResult<Pattern> {
     Ok(match self.token_handler.peek_kind() {
       Identifier(_) => {
-        let qualified_name = self.qualified_identifier()?;
+        let components = self.qualified_identifier()?;
+        let qualified_identifier = QualifiedName { id: self.id_store.fresh(), components };
         match self.token_handler.peek_kind() {
           LCurlyBrace => {
             let members = delimited!(self, LCurlyBrace, record_pattern_entry, Comma, RCurlyBrace);
-            Pattern::Record(qualified_name, members)
+            Pattern::Record(qualified_identifier, members)
           },
           LParen => {
             let members = delimited!(self, LParen, pattern, Comma, RParen);
-            Pattern::TupleStruct(qualified_name, members)
+            Pattern::TupleStruct(qualified_identifier, members)
           },
           _ => {
-            Pattern::VarOrName(qualified_name)
+            Pattern::VarOrName(qualified_identifier)
           },
         }
       },
@@ -968,7 +991,7 @@ impl Parser {
         self.token_handler.next();
         Pattern::Literal(PatternLiteral::BoolPattern(false))
       },
-      StrLiteral(s) => {
+      StrLiteral { s, .. } => {
         self.token_handler.next();
         Pattern::Literal(PatternLiteral::StringPattern(s))
       },
@@ -982,50 +1005,6 @@ impl Parser {
     })
   }
 
-  /*
-  #[recursive_descent_method]
-  fn simple_pattern(&mut self) -> ParseResult<Pattern> {
-    Ok({
-      let tok = self.token_handler.peek();
-      match tok.get_kind() {
-        Identifier(_) => {
-          let id = self.identifier()?;
-          match self.token_handler.peek_kind() {
-            LCurlyBrace => {
-              let members = delimited!(self, LCurlyBrace, record_pattern_entry, Comma, RCurlyBrace);
-              Pattern::Record(id, members)
-            },
-            LParen => {
-              let members = delimited!(self, LParen, pattern, Comma, RParen);
-              Pattern::TupleStruct(id, members)
-            },
-            _ => Pattern::Literal(PatternLiteral::VarPattern(id))
-          }
-        },
-        Keyword(Kw::True) => {
-          self.token_handler.next();
-          Pattern::Literal(PatternLiteral::BoolPattern(true))
-        },
-        Keyword(Kw::False) => {
-          self.token_handler.next();
-          Pattern::Literal(PatternLiteral::BoolPattern(false))
-        },
-        StrLiteral(s) => {
-          self.token_handler.next();
-          Pattern::Literal(PatternLiteral::StringPattern(s))
-        },
-        DigitGroup(_) | HexLiteral(_) | BinNumberSigil | Period => self.signed_number_literal()?,
-        Operator(ref op) if **op == "-" => self.signed_number_literal()?,
-        Underscore => {
-          self.token_handler.next();
-          Pattern::Ignored
-        },
-        other => return ParseError::new_with_token(format!("{:?} is not a valid Pattern", other), tok)
-      }
-    })
-  }
-  */
-
   #[recursive_descent_method]
   fn signed_number_literal(&mut self) -> ParseResult<Pattern> {
     let neg = match self.token_handler.peek_kind() {
@@ -1064,7 +1043,7 @@ impl Parser {
       LCurlyBrace => self.block(),
       _ => {
         let expr = self.expression()?;
-        let s = Statement { id: self.id_store.fresh(), kind: StatementKind::Expression(expr.into()) };
+        let s = Statement { id: self.id_store.fresh(), kind: StatementKind::Expression(expr) };
         Ok(vec![s])
       }
     }
@@ -1078,7 +1057,7 @@ impl Parser {
       self.restrictions.no_struct_literal = true;
       let x = self.while_cond();
       self.restrictions.no_struct_literal = false;
-      x?.map(|expr| bx!(expr.into()))
+      x?.map(|expr| bx!(expr))
     };
     let body = self.block()?;
     Ok(Expression::new(self.id_store.fresh(), WhileExpression {condition, body}))
@@ -1114,7 +1093,7 @@ impl Parser {
   fn enumerator(&mut self) -> ParseResult<Enumerator> {
     let id = self.identifier()?;
     expect!(self, Operator(ref c) if **c == "<-");
-    let generator = self.expression()?.into();
+    let generator = self.expression()?;
     Ok(Enumerator { id, generator })
   }
 
@@ -1129,7 +1108,7 @@ impl Parser {
       },
       Keyword(Kw::Return) => {
         self.token_handler.next();
-        MonadicReturn(self.expression()?.into())
+        MonadicReturn(self.expression()?)
       },
       _ => return ParseError::new_with_token("for expressions must end in a block or 'return'", tok),
     })
@@ -1161,7 +1140,7 @@ impl Parser {
         let id = self.id_store.fresh();
         Ok(Expression::new(id, BoolLiteral(false)))
       },
-      StrLiteral(s) => {
+      StrLiteral {s, ..} => {
         self.token_handler.next();
         let id = self.id_store.fresh();
         Ok(Expression::new(id, StringLiteral(s.clone())))
@@ -1231,6 +1210,67 @@ impl Parser {
     }
     Ok(ds)
   }
+
+  #[recursive_descent_method]
+  fn import_declaration(&mut self) -> ParseResult<ImportSpecifier> {
+    expect!(self, Keyword(Import));
+    let mut path_components = vec![];
+    path_components.push(self.identifier()?);
+    loop {
+      match (self.token_handler.peek_kind(), self.token_handler.peek_kind_n(1)) {
+        (Colon, Colon) => {
+          self.token_handler.next(); self.token_handler.next();
+          if let Identifier(_) = self.token_handler.peek_kind() {
+            path_components.push(self.identifier()?);
+          } else {
+            break;
+          }
+        },
+        _ => break,
+      }
+    }
+
+    let imported_names = match self.token_handler.peek_kind() {
+      LCurlyBrace => {
+        let names = delimited!(self, LCurlyBrace, identifier, Comma, RCurlyBrace);
+        ImportedNames::List(names)
+      },
+      Operator(ref s) if **s == "*" => {
+        self.token_handler.next();
+        ImportedNames::All
+      },
+      _ => ImportedNames::LastOfPath
+    };
+
+    Ok(ImportSpecifier {
+      id: self.id_store.fresh(),
+      path_components,
+      imported_names
+    })
+  }
+
+  #[recursive_descent_method]
+  fn import_suffix(&mut self) -> ParseResult<ImportedNames> {
+    Ok(match self.token_handler.peek_kind() {
+      Operator(ref s) if **s == "*" => {
+        self.token_handler.next();
+        ImportedNames::All
+      },
+      LCurlyBrace => {
+        let names = delimited!(self, LCurlyBrace, identifier, Comma, RCurlyBrace);
+        ImportedNames::List(names)
+      },
+      _ => return ParseError::new_with_token("Expected '{{' or '*'", self.token_handler.peek()),
+    })
+  }
+
+  #[recursive_descent_method]
+  fn module_declaration(&mut self) -> ParseResult<ModuleSpecifier> {
+    expect!(self, Keyword(Kw::Module));
+    let name = self.identifier()?;
+    let contents = delimited!(self, LCurlyBrace, statement, Newline | Semicolon, RCurlyBrace, nonstrict);
+    Ok(ModuleSpecifier { name, contents })
+  }
 }
 
 fn parse_binary(digits: String, tok: Token) -> ParseResult<u64> {
@@ -1265,3 +1305,4 @@ fn parse_hex(digits: String, tok: Token) -> ParseResult<u64> {
   }
   Ok(result)
 }
+

schala-lang/language/src/parsing/test.rs

@@ -1,10 +1,10 @@
 #![cfg(test)]
-use ::std::rc::Rc;
+use std::cell::RefCell;
+use std::rc::Rc;
 use std::str::FromStr;
 
-use super::tokenize;
-use super::ParseResult;
-use crate::ast::{ItemIdStore, AST, Meta, Expression, Statement, StatementKind, IfExpressionBody, Discriminator, Pattern, PatternLiteral, TypeBody, Enumerator, ForBody, InvocationArgument, FormalParam, PrefixOp, BinOp, QualifiedName};
+use super::{Parser, ParseResult, tokenize};
+use crate::ast::*;
 use super::Declaration::*;
 use super::Signature;
 use super::TypeIdentifier::*;
@@ -13,9 +13,17 @@ use super::ExpressionKind::*;
 use super::Variant::*;
 use super::ForBody::*;
 
-fn parse(input: &str) -> ParseResult<AST> {
+fn make_parser(input: &str) -> Parser {
+  let source_map = crate::source_map::SourceMap::new();
+  let source_map_handle = Rc::new(RefCell::new(source_map));
   let tokens: Vec<crate::tokenizing::Token> = tokenize(input);
-  let mut parser = super::Parser::new(tokens);
+  let mut parser = super::Parser::new(source_map_handle);
+  parser.add_new_tokens(tokens);
+  parser
+}
+
+fn parse(input: &str) -> ParseResult<AST> {
+  let mut parser = make_parser(input);
   parser.parse()
 }
 
@@ -57,14 +65,24 @@ macro_rules! decl {
   };
 }
 
+macro_rules! import {
+  ($import_spec:expr) => {
+    Statement { id: ItemIdStore::new_id(), kind: StatementKind::Import($import_spec) }
+  }
+}
+
+macro_rules! module {
+  ($module_spec:expr) => {
+    Statement { id: ItemIdStore::new_id(), kind: StatementKind::Module($module_spec) }
+  }
+}
+
 macro_rules! ex {
   ($expr_type:expr) => { Expression::new(ItemIdStore::new_id(), $expr_type) };
-  (m $expr_type:expr) => { Meta::new(Expression::new(ItemIdStore::new_id(), $expr_type)) };
-  (m $expr_type:expr, $type_anno:expr) => { Meta::new(Expression::with_anno(ItemIdStore::new_id(), $expr_type, $type_anno)) };
+  ($expr_type:expr, $type_anno:expr) => { Expression::with_anno(ItemIdStore::new_id(), $expr_type, $type_anno) };
   (s $expr_text:expr) => {
     {
-      let tokens: Vec<crate::tokenizing::Token> = tokenize($expr_text);
-      let mut parser = super::Parser::new(tokens);
+      let mut parser = make_parser($expr_text);
       parser.expression().unwrap()
     }
   };
@@ -81,16 +99,14 @@ macro_rules! prefexp {
   ($op:expr, $lhs:expr) => { PrefixExp(PrefixOp::from_str($op).unwrap(), bx!(Expression::new(ItemIdStore::new_id(), $lhs).into())) }
 }
 macro_rules! exst {
-  ($expr_type:expr) => { Meta::new(Statement { id: ItemIdStore::new_id(), kind: StatementKind::Expression(Expression::new(ItemIdStore::new_id(), $expr_type).into())}) };
-  ($expr_type:expr, $type_anno:expr) => { Meta::new(Statement { id: ItemIdStore::new_id(), kind: StatementKind::Expression(Expression::with_anno(ItemIdStore::new_id(), $expr_type, $type_anno).into())}) };
-  ($op:expr, $lhs:expr, $rhs:expr) => { Meta::new(
-    Statement { id: ItemIdStore::new_id(), ,kind: StatementKind::Expression(ex!(binexp!($op, $lhs, $rhs)))}
-  )};
+  ($expr_type:expr) => { Statement { id: ItemIdStore::new_id(), kind: StatementKind::Expression(Expression::new(ItemIdStore::new_id(), $expr_type).into())} };
+  ($expr_type:expr, $type_anno:expr) => { Statement { id: ItemIdStore::new_id(), kind: StatementKind::Expression(Expression::with_anno(ItemIdStore::new_id(), $expr_type, $type_anno).into())} };
+  ($op:expr, $lhs:expr, $rhs:expr) => { Statement { id: ItemIdStore::new_id(), ,kind: StatementKind::Expression(ex!(binexp!($op, $lhs, $rhs)))}
+  };
   (s $statement_text:expr) => {
     {
-      let tokens: Vec<crate::tokenizing::Token> = tokenize($statement_text);
-      let mut parser = super::Parser::new(tokens);
-      Meta::new(parser.statement().unwrap())
+      let mut parser = make_parser($statement_text);
+      parser.statement().unwrap()
     }
   }
 }
@@ -170,15 +186,15 @@ fn parsing_identifiers() {
   ])
   }
   */
-  parse_test_wrap_ast!("a[b,c]", exst!(Index { indexee: bx!(ex!(m val!("a"))), indexers: vec![ex!(m val!("b")), ex!(m val!("c"))]} ));
+  parse_test_wrap_ast!("a[b,c]", exst!(Index { indexee: bx!(ex!(val!("a"))), indexers: vec![ex!(val!("b")), ex!(val!("c"))]} ));
 
   parse_test_wrap_ast!("None", exst!(val!("None")));
   parse_test_wrap_ast!("Pandas {  a: x + y }",
-    exst!(NamedStruct { name: Meta::new(qname!(Pandas)), fields: vec![(rc!(a), ex!(m binexp!("+", val!("x"), val!("y"))))]})
+    exst!(NamedStruct { name: qname!(Pandas), fields: vec![(rc!(a), ex!(binexp!("+", val!("x"), val!("y"))))]})
   );
   parse_test_wrap_ast! { "Pandas { a: n, b: q, }",
-    exst!(NamedStruct { name: Meta::new(qname!(Pandas)), fields:
-    vec![(rc!(a), ex!(m val!("n"))), (rc!(b), ex!(m val!("q")))]
+    exst!(NamedStruct { name: qname!(Pandas), fields:
+    vec![(rc!(a), ex!(val!("n"))), (rc!(b), ex!(val!("q")))]
     }
     )
   };
@@ -189,14 +205,14 @@ fn parsing_identifiers() {
 fn qualified_identifiers() {
   parse_test_wrap_ast! {
     "let q_q = Yolo::Swaggins",
-    Meta::new(decl!(Binding { name: rc!(q_q), constant: true, type_anno: None,
-      expr: Meta::new(Expression::new(ItemIdStore::new_id(), Value(qname!(Yolo, Swaggins)))),
-    }))
+    decl!(Binding { name: rc!(q_q), constant: true, type_anno: None,
+    expr: Expression::new(ItemIdStore::new_id(), Value(qname!(Yolo, Swaggins))),
+    })
   }
 
   parse_test_wrap_ast! {
     "thing::item::call()",
-    exst!(Call { f: bx![ex!(m Value(qname!(thing, item, call)))], arguments: vec![] })
+    exst!(Call { f: bx![ex!(Value(qname!(thing, item, call)))], arguments: vec![] })
   }
 }
 
@@ -224,36 +240,36 @@ fn parsing_complicated_operators() {
 
 #[test]
 fn parsing_functions() {
-  parse_test_wrap_ast!("fn oi()",  Meta::new(decl!(FuncSig(Signature { name: rc!(oi), operator: false, params: vec![], type_anno: None }))));
-  parse_test_wrap_ast!("oi()", exst!(Call { f: bx!(ex!(m val!("oi"))), arguments: vec![] }));
+  parse_test_wrap_ast!("fn oi()",  decl!(FuncSig(Signature { name: rc!(oi), operator: false, params: vec![], type_anno: None })));
+  parse_test_wrap_ast!("oi()", exst!(Call { f: bx!(ex!(val!("oi"))), arguments: vec![] }));
   parse_test_wrap_ast!("oi(a, 2 + 2)", exst!(Call
-  { f: bx!(ex!(m val!("oi"))),
-    arguments: vec![inv!(ex!(m val!("a"))), inv!(ex!(m binexp!("+", NatLiteral(2), NatLiteral(2)))).into()]
+  { f: bx!(ex!(val!("oi"))),
+    arguments: vec![inv!(ex!(val!("a"))), inv!(ex!(binexp!("+", NatLiteral(2), NatLiteral(2)))).into()]
   }));
   parse_error!("a(b,,c)");
 
-  parse_test_wrap_ast!("fn a(b, c: Int): Int", Meta::new(decl!(
-    FuncSig(Signature { name: rc!(a), operator: false, params: vec![
-      FormalParam { name: rc!(b), anno: None, default: None },
-      FormalParam { name: rc!(c), anno: Some(ty!("Int")), default: None }
-    ], type_anno: Some(ty!("Int")) }))));
+  parse_test_wrap_ast!("fn a(b, c: Int): Int", decl!(
+      FuncSig(Signature { name: rc!(a), operator: false, params: vec![
+        FormalParam { name: rc!(b), anno: None, default: None },
+        FormalParam { name: rc!(c), anno: Some(ty!("Int")), default: None }
+      ], type_anno: Some(ty!("Int")) })));
 
 
-  parse_test_wrap_ast!("fn a(x) { x() }", Meta::new(decl!(
-    FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), anno: None, default: None }], type_anno: None },
-      vec![exst!(Call { f: bx!(ex!(m val!("x"))), arguments: vec![] })]))));
-  parse_test_wrap_ast!("fn a(x) {\n x() }", Meta::new(decl!(
-    FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), anno: None, default: None }], type_anno: None },
-      vec![exst!(Call { f: bx!(ex!(m val!("x"))), arguments: vec![] })]))));
+  parse_test_wrap_ast!("fn a(x) { x() }", decl!(
+      FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), anno: None, default: None }], type_anno: None },
+      vec![exst!(Call { f: bx!(ex!(val!("x"))), arguments: vec![] })])));
+  parse_test_wrap_ast!("fn a(x) {\n x() }", decl!(
+      FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), anno: None, default: None }], type_anno: None },
+      vec![exst!(Call { f: bx!(ex!(val!("x"))), arguments: vec![] })])));
 
   let multiline = r#"
 fn a(x) {
 x()
 }
 "#;
-  parse_test_wrap_ast!(multiline, Meta::new(decl!(
+parse_test_wrap_ast!(multiline, decl!(
     FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), default: None, anno: None }], type_anno: None },
-      vec![exst!(Call { f: bx!(ex!(m val!("x"))), arguments: vec![] })]))));
+    vec![exst!(Call { f: bx!(ex!(val!("x"))), arguments: vec![] })])));
   let multiline2 = r#"
 fn a(x) {
 
@@ -261,21 +277,21 @@ x()
 
 }
 "#;
-  parse_test_wrap_ast!(multiline2, Meta::new(decl!(
+parse_test_wrap_ast!(multiline2, decl!(
     FuncDecl(Signature { name: rc!(a), operator: false, params: vec![FormalParam { name: rc!(x), default: None, anno: None }], type_anno: None },
-      vec![exst!(s "x()")]))));
+    vec![exst!(s "x()")])));
 }
 
 #[test]
 fn functions_with_default_args() {
   parse_test_wrap_ast! {
     "fn func(x: Int, y: Int = 4) { }",
-    Meta::new(decl!(
+    decl!(
       FuncDecl(Signature { name: rc!(func), operator: false, type_anno: None, params: vec![
         FormalParam { name: rc!(x), default: None, anno: Some(ty!("Int")) },
-        FormalParam { name: rc!(y), default: Some(Meta::new(ex!(s "4"))), anno: Some(ty!("Int")) }
+        FormalParam { name: rc!(y), default: Some(ex!(s "4")), anno: Some(ty!("Int")) }
       ]}, vec![])
-    ))
+    )
   };
 }
 
@@ -292,11 +308,11 @@ fn parsing_strings() {
 
 #[test]
 fn parsing_types() {
-  parse_test_wrap_ast!("type Yolo = Yolo", Meta::new(decl!(TypeDecl { name: tys!("Yolo"), body: TypeBody(vec![UnitStruct(rc!(Yolo))]), mutable: false} )));
-  parse_test_wrap_ast!("type mut Yolo = Yolo", Meta::new(decl!(TypeDecl { name: tys!("Yolo"), body: TypeBody(vec![UnitStruct(rc!(Yolo))]), mutable: true} )));
-  parse_test_wrap_ast!("type alias Sex = Drugs", Meta::new(decl!(TypeAlias(rc!(Sex), rc!(Drugs)))));
+  parse_test_wrap_ast!("type Yolo = Yolo", decl!(TypeDecl { name: tys!("Yolo"), body: TypeBody(vec![UnitStruct(rc!(Yolo))]), mutable: false} ));
+  parse_test_wrap_ast!("type mut Yolo = Yolo", decl!(TypeDecl { name: tys!("Yolo"), body: TypeBody(vec![UnitStruct(rc!(Yolo))]), mutable: true} ));
+  parse_test_wrap_ast!("type alias Sex = Drugs", decl!(TypeAlias { alias: rc!(Sex), original: rc!(Drugs) }));
   parse_test_wrap_ast!("type Sanchez = Miguel | Alejandro(Int, Option<a>) | Esperanza { a: Int, b: String }",
-  Meta::new(decl!(TypeDecl {
+  decl!(TypeDecl {
     name: tys!("Sanchez"),
     body: TypeBody(vec![
       UnitStruct(rc!(Miguel)),
@@ -313,27 +329,27 @@ fn parsing_types() {
       }
     ]),
     mutable: false
-   })));
+  }));
 
   parse_test_wrap_ast! {
     "type Jorge<a> = Diego | Kike(a)",
-    Meta::new(decl!(TypeDecl{
+    decl!(TypeDecl{
       name: TypeSingletonName { name: rc!(Jorge), params: vec![Singleton(TypeSingletonName { name: rc!(a), params: vec![] })] },
       body: TypeBody(vec![UnitStruct(rc!(Diego)), TupleStruct(rc!(Kike), vec![Singleton(TypeSingletonName { name: rc!(a), params: vec![] })])]),
       mutable: false
     }
-  ))
+    )
   };
 }
 
 #[test]
 fn parsing_bindings() {
-  parse_test_wrap_ast!("let mut a = 10", Meta::new(decl!(Binding { name: rc!(a), constant: false, type_anno: None, expr: ex!(m NatLiteral(10)) } )));
-  parse_test_wrap_ast!("let a = 2 + 2", Meta::new(decl!(Binding { name: rc!(a), constant: true, type_anno: None, expr: ex!(m binexp!("+", NatLiteral(2), NatLiteral(2))) }) ));
-  parse_test_wrap_ast!("let a: Nat = 2 + 2", Meta::new(decl!(
-    Binding { name: rc!(a), constant: true, type_anno: Some(Singleton(TypeSingletonName { name: rc!(Nat), params: vec![] })),
-    expr: Meta::new(ex!(binexp!("+", NatLiteral(2), NatLiteral(2)))) }
-  )));
+  parse_test_wrap_ast!("let mut a = 10", decl!(Binding { name: rc!(a), constant: false, type_anno: None, expr: ex!(NatLiteral(10)) } ));
+  parse_test_wrap_ast!("let a = 2 + 2", decl!(Binding { name: rc!(a), constant: true, type_anno: None, expr: ex!(binexp!("+", NatLiteral(2), NatLiteral(2))) }));
+  parse_test_wrap_ast!("let a: Nat = 2 + 2", decl!(
+      Binding { name: rc!(a), constant: true, type_anno: Some(Singleton(TypeSingletonName { name: rc!(Nat), params: vec![] })),
+      expr: ex!(binexp!("+", NatLiteral(2), NatLiteral(2))) }
+  ));
 }
 
 #[test]
@@ -341,14 +357,14 @@ fn parsing_block_expressions() {
   parse_test_wrap_ast! {
     "if a() then { b(); c() }", exst!(
       IfExpression {
-        discriminator: bx! {
-          Discriminator::Simple(ex!(m Call { f: bx!(ex!(m val!("a"))), arguments: vec![]}))
-        },
+        discriminator: Some(bx! {
+          ex!(Call { f: bx!(ex!(val!("a"))), arguments: vec![]})
+        }),
         body: bx! {
-          IfExpressionBody::SimpleConditional(
-            vec![exst!(Call { f: bx!(ex!(m val!("b"))), arguments: vec![]}), exst!(Call { f: bx!(ex!(m val!("c"))), arguments: vec![] })],
-            None
-          )
+          IfExpressionBody::SimpleConditional {
+            then_case: vec![exst!(Call { f: bx!(ex!(val!("b"))), arguments: vec![]}), exst!(Call { f: bx!(ex!(val!("c"))), arguments: vec![] })],
+            else_case: None,
+          }
         }
       }
     )
@@ -357,16 +373,14 @@ fn parsing_block_expressions() {
   parse_test_wrap_ast! {
     "if a() then { b(); c() } else { q }", exst!(
       IfExpression {
-        discriminator: bx! {
-          Discriminator::Simple(ex!(m Call { f: bx!(ex!(m val!("a"))), arguments: vec![]}))
-        },
+        discriminator: Some(bx! {
+          ex!(Call { f: bx!(ex!(val!("a"))), arguments: vec![]})
+        }),
         body: bx! {
-          IfExpressionBody::SimpleConditional(
-            vec![exst!(Call { f: bx!(ex!(m val!("b"))), arguments: vec![]}), exst!(Call { f: bx!(ex!(m val!("c"))), arguments: vec![] })],
-            Some(
-              vec![exst!(val!("q"))],
-            )
-          )
+          IfExpressionBody::SimpleConditional {
+            then_case: vec![exst!(Call { f: bx!(ex!(val!("b"))), arguments: vec![]}), exst!(Call { f: bx!(ex!(val!("c"))), arguments: vec![] })],
+            else_case: Some(vec![exst!(val!("q"))]),
+          }
         }
       }
     )
@@ -407,69 +421,66 @@ fn parsing_block_expressions() {
 #[test]
 fn parsing_interfaces() {
   parse_test_wrap_ast!("interface Unglueable { fn unglue(a: Glue); fn mar(): Glue }",
-    Meta::new(decl!(Interface {
-      name: rc!(Unglueable),
-      signatures: vec![
-        Signature {
-          name: rc!(unglue),
-          operator: false,
-          params: vec![
-            FormalParam { name: rc!(a), anno: Some(Singleton(TypeSingletonName { name: rc!(Glue), params: vec![] })), default: None }
-          ],
-          type_anno: None
-        },
-        Signature { name: rc!(mar), operator: false, params: vec![], type_anno: Some(Singleton(TypeSingletonName { name: rc!(Glue), params: vec![] })) },
-      ]
-    }))
+  decl!(Interface {
+    name: rc!(Unglueable),
+    signatures: vec![
+      Signature {
+        name: rc!(unglue),
+        operator: false,
+        params: vec![
+          FormalParam { name: rc!(a), anno: Some(Singleton(TypeSingletonName { name: rc!(Glue), params: vec![] })), default: None }
+        ],
+        type_anno: None
+      },
+      Signature { name: rc!(mar), operator: false, params: vec![], type_anno: Some(Singleton(TypeSingletonName { name: rc!(Glue), params: vec![] })) },
+    ]
+  })
   );
 }
 
 #[test]
 fn parsing_impls() {
   parse_test_wrap_ast!("impl Heh { fn yolo(); fn swagg(); }",
-    Meta::new(
-    decl!(Impl {
-      type_name: ty!("Heh"),
-      interface_name: None,
-      block: vec![
-        FuncSig(Signature { name: rc!(yolo), operator: false, params: vec![], type_anno: None }),
-        FuncSig(Signature { name: rc!(swagg), operator: false, params: vec![], type_anno: None })
-      ] })));
+  decl!(Impl {
+    type_name: ty!("Heh"),
+    interface_name: None,
+    block: vec![
+      FuncSig(Signature { name: rc!(yolo), operator: false, params: vec![], type_anno: None }),
+      FuncSig(Signature { name: rc!(swagg), operator: false, params: vec![], type_anno: None })
+    ] }));
 
   parse_test_wrap_ast!("impl Mondai for Lollerino { fn yolo(); fn swagg(); }",
-    Meta::new(decl!(Impl {
-      type_name: ty!("Lollerino"),
-      interface_name: Some(TypeSingletonName { name: rc!(Mondai), params: vec![] }),
-      block: vec![
-        FuncSig(Signature { name: rc!(yolo), operator: false, params: vec![], type_anno: None}),
-        FuncSig(Signature { name: rc!(swagg), operator: false, params: vec![], type_anno: None })
-      ] })));
+  decl!(Impl {
+    type_name: ty!("Lollerino"),
+    interface_name: Some(TypeSingletonName { name: rc!(Mondai), params: vec![] }),
+    block: vec![
+      FuncSig(Signature { name: rc!(yolo), operator: false, params: vec![], type_anno: None}),
+      FuncSig(Signature { name: rc!(swagg), operator: false, params: vec![], type_anno: None })
+    ] }));
 
   parse_test_wrap_ast!("impl Hella<T> for (Alpha, Omega) { }",
-    Meta::new(decl!(Impl {
-      type_name: Tuple(vec![ty!("Alpha"), ty!("Omega")]),
-      interface_name: Some(TypeSingletonName { name: rc!(Hella), params: vec![ty!("T")] }),
-      block: vec![]
-    }))
+  decl!(Impl {
+    type_name: Tuple(vec![ty!("Alpha"), ty!("Omega")]),
+    interface_name: Some(TypeSingletonName { name: rc!(Hella), params: vec![ty!("T")] }),
+    block: vec![]
+  })
   );
 
   parse_test_wrap_ast!("impl Option<WTFMate> { fn oi() }",
-    Meta::new(
-    decl!(Impl {
-      type_name: Singleton(TypeSingletonName { name: rc!(Option), params: vec![ty!("WTFMate")]}),
-      interface_name: None,
-      block: vec![
-        FuncSig(Signature { name: rc!(oi), operator: false, params: vec![], type_anno: None }),
-      ]
-    })));
+  decl!(Impl {
+    type_name: Singleton(TypeSingletonName { name: rc!(Option), params: vec![ty!("WTFMate")]}),
+    interface_name: None,
+    block: vec![
+      FuncSig(Signature { name: rc!(oi), operator: false, params: vec![], type_anno: None }),
+    ]
+  }));
 }
 
 #[test]
 fn parsing_type_annotations() {
   parse_test_wrap_ast!("let a = b : Int",
-    Meta::new(
     decl!(Binding { name: rc!(a), constant: true, type_anno: None, expr:
-      ex!(m val!("b"), ty!("Int")) })));
+      ex!(val!("b"), ty!("Int")) }));
 
   parse_test_wrap_ast!("a : Int",
     exst!(val!("a"), ty!("Int"))
@@ -511,7 +522,7 @@ fn parsing_lambdas() {
   );
 
   parse_test_wrap_ast! { r#"\(x){y}(1)"#,
-    exst!(Call { f: bx!(ex!(m
+    exst!(Call { f: bx!(ex!(
       Lambda {
         params: vec![
           FormalParam { name: rc!(x), anno: None, default: None }
@@ -519,7 +530,7 @@ fn parsing_lambdas() {
         type_anno: None,
         body: vec![exst!(s "y")] }
       )),
-      arguments: vec![inv!(ex!(m NatLiteral(1))).into()] })
+      arguments: vec![inv!(ex!(NatLiteral(1))).into()] })
   };
 
   parse_test_wrap_ast! {
@@ -566,8 +577,8 @@ fn more_advanced_lambdas() {
         exst!(s r"fn wahoo() { let a = 10; \(x) { x + a } }"),
         exst! {
         Call {
-          f: bx!(ex!(m Call { f: bx!(ex!(m val!("wahoo"))), arguments: vec![] })),
-          arguments: vec![inv!(ex!(m NatLiteral(3))).into()],
+          f: bx!(ex!(Call { f: bx!(ex!(val!("wahoo"))), arguments: vec![] })),
+          arguments: vec![inv!(ex!(NatLiteral(3))).into()],
         }
       }
     ]
@@ -579,7 +590,7 @@ fn more_advanced_lambdas() {
   fn list_literals() {
     parse_test_wrap_ast! {
       "[1,2]",
-        exst!(ListLiteral(vec![ex!(m NatLiteral(1)), ex!(m NatLiteral(2))]))
+        exst!(ListLiteral(vec![ex!(NatLiteral(1)), ex!(NatLiteral(2))]))
     };
   }
 
@@ -592,7 +603,7 @@ fn while_expr() {
 
   parse_test_wrap_ast! {
     "while a == b { }",
-    exst!(WhileExpression { condition: Some(bx![ex![m binexp!("==", val!("a"), val!("b"))]]), body: vec![] })
+    exst!(WhileExpression { condition: Some(bx![ex![binexp!("==", val!("a"), val!("b"))]]), body: vec![] })
   }
 }
 
@@ -619,31 +630,41 @@ fn patterns() {
   parse_test_wrap_ast! {
     "if x is Some(a) then { 4 } else { 9 }", exst!(
       IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(Pattern::TupleStruct(qname!(Some),
-            vec![Pattern::VarOrName(qname!(a))]), vec![exst!(s "4")], Some(vec![exst!(s "9")]))) }
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::SimplePatternMatch {
+          pattern: Pattern::TupleStruct(qname!(Some), vec![Pattern::VarOrName(qname!(a))]),
+          then_case: vec![exst!(s "4")],
+          else_case: Some(vec![exst!(s "9")]) })
+        }
       )
   }
 
   parse_test_wrap_ast! {
     "if x is Some(a) then 4 else 9", exst!(
       IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(Pattern::TupleStruct(qname!(Some),
-              vec![Pattern::VarOrName(qname!(a))]), vec![exst!(s "4")], Some(vec![exst!(s "9")]))) }
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::SimplePatternMatch {
+            pattern: Pattern::TupleStruct(qname!(Some), vec![Pattern::VarOrName(qname!(a))]),
+            then_case: vec![exst!(s "4")],
+            else_case: Some(vec![exst!(s "9")]) }
+          )
+        }
     )
   }
 
   parse_test_wrap_ast! {
     "if x is Something { a, b: x } then { 4 } else { 9 }", exst!(
       IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(
-            Pattern::Record(qname!(Something), vec![
-              (rc!(a),Pattern::Literal(PatternLiteral::StringPattern(rc!(a)))),
-              (rc!(b),Pattern::VarOrName(qname!(x)))
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::SimplePatternMatch {
+          pattern: Pattern::Record(qname!(Something), vec![
+                (rc!(a),Pattern::Literal(PatternLiteral::StringPattern(rc!(a)))),
+                (rc!(b),Pattern::VarOrName(qname!(x)))
             ]),
-            vec![exst!(s "4")], Some(vec![exst!(s "9")])))
+          then_case: vec![exst!(s "4")],
+          else_case: Some(vec![exst!(s "9")])
+          }
+        )
       }
     )
   }
@@ -655,12 +676,12 @@ fn pattern_literals() {
     "if x is -1 then 1 else 2",
     exst!(
       IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(
-          Pattern::Literal(PatternLiteral::NumPattern { neg: true, num: NatLiteral(1) }),
-          vec![exst!(NatLiteral(1))],
-          Some(vec![exst!(NatLiteral(2))]),
-        ))
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::SimplePatternMatch {
+            pattern: Pattern::Literal(PatternLiteral::NumPattern { neg: true, num: NatLiteral(1) }),
+            then_case: vec![exst!(NatLiteral(1))],
+            else_case: Some(vec![exst!(NatLiteral(2))]),
+        })
       }
     )
   }
@@ -669,12 +690,12 @@ fn pattern_literals() {
     "if x is 1 then 1 else 2",
     exst!(
       IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(
-            Pattern::Literal(PatternLiteral::NumPattern { neg: false, num: NatLiteral(1) }),
-            vec![exst!(s "1")],
-            Some(vec![exst!(s "2")]),
-            ))
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::SimplePatternMatch {
+          pattern: Pattern::Literal(PatternLiteral::NumPattern { neg: false, num: NatLiteral(1) }),
+          then_case: vec![exst!(s "1")],
+          else_case: Some(vec![exst!(s "2")]),
+        })
       }
     )
   }
@@ -683,12 +704,13 @@ fn pattern_literals() {
     "if x is true then 1 else 2",
     exst!(
     IfExpression {
-        discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-        body: bx!(IfExpressionBody::SimplePatternMatch(
-        Pattern::Literal(PatternLiteral::BoolPattern(true)),
-        vec![exst!(NatLiteral(1))],
-        Some(vec![exst!(NatLiteral(2))]),
-        ))
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(
+            IfExpressionBody::SimplePatternMatch {
+              pattern: Pattern::Literal(PatternLiteral::BoolPattern(true)),
+              then_case: vec![exst!(NatLiteral(1))],
+              else_case: Some(vec![exst!(NatLiteral(2))]),
+          })
       }
     )
   }
@@ -697,13 +719,110 @@ fn pattern_literals() {
     "if x is \"gnosticism\" then 1 else 2",
       exst!(
         IfExpression {
-          discriminator: bx!(Discriminator::Simple(Meta::new(ex!(s "x")))),
-          body: bx!(IfExpressionBody::SimplePatternMatch(
-              Pattern::Literal(PatternLiteral::StringPattern(rc!(gnosticism))),
-              vec![exst!(s "1")],
-              Some(vec![exst!(s "2")]),
-              ))
+          discriminator: Some(bx!(ex!(s "x"))),
+          body: bx!(IfExpressionBody::SimplePatternMatch {
+              pattern: Pattern::Literal(PatternLiteral::StringPattern(rc!(gnosticism))),
+              then_case: vec![exst!(s "1")],
+              else_case: Some(vec![exst!(s "2")]),
+          })
         }
       )
   }
 }
+
+#[test]
+fn imports() {
+  parse_test_wrap_ast! {
+    "import harbinger::draughts::Norgleheim",
+    import!(ImportSpecifier { 
+      id: ItemIdStore::new_id(),
+      path_components: vec![rc!(harbinger), rc!(draughts), rc!(Norgleheim)],
+      imported_names: ImportedNames::LastOfPath
+    })
+  }
+}
+
+#[test]
+fn imports_2() {
+  parse_test_wrap_ast! {
+    "import harbinger::draughts::{Norgleheim, Xraksenlaigar}",
+    import!(ImportSpecifier { 
+      id: ItemIdStore::new_id(),
+      path_components: vec![rc!(harbinger), rc!(draughts)],
+      imported_names: ImportedNames::List(vec![
+        rc!(Norgleheim),
+        rc!(Xraksenlaigar)
+      ])
+    })
+  }
+}
+
+#[test]
+fn imports_3() {
+  parse_test_wrap_ast! {
+    "import bespouri::{}",
+    import!(ImportSpecifier { 
+      id: ItemIdStore::new_id(),
+      path_components: vec![rc!(bespouri)],
+      imported_names: ImportedNames::List(vec![])
+    })
+  }
+}
+
+
+#[test]
+fn imports_4() {
+  parse_test_wrap_ast! {
+    "import bespouri::*",
+    import!(ImportSpecifier {
+      id: ItemIdStore::new_id(),
+      path_components: vec![rc!(bespouri)],
+      imported_names: ImportedNames::All
+    })
+  }
+}
+
+
+#[test]
+fn if_expr() {
+  parse_test_wrap_ast! {
+    "if x { is 1 then 5, else 20 }",
+    exst! {
+      IfExpression {
+        discriminator: Some(bx!(ex!(s "x"))),
+        body: bx!(IfExpressionBody::CondList(
+          vec![
+            ConditionArm {
+              condition: Condition::Pattern(Pattern::Literal(PatternLiteral::NumPattern { neg: false, num: NatLiteral(1)})),
+              guard: None,
+              body: vec![exst!(s "5")],
+            },
+            ConditionArm {
+              condition: Condition::Else,
+              guard: None,
+              body: vec![exst!(s "20")],
+            },
+          ]
+        ))
+      }
+    }
+  }
+}
+
+#[test]
+fn modules() {
+  parse_test_wrap_ast! {
+r#"
+  module ephraim {
+    let a = 10
+    fn nah() { 33 }
+  }
+"#,
+module!(
+  ModuleSpecifier { name: rc!(ephraim), contents: vec![
+    decl!(Binding { name: rc!(a), constant: true, type_anno: None, expr: ex!(s "10") }),
+    decl!(FuncDecl(Signature { name: rc!(nah), operator: false, params: vec![], type_anno: None }, vec![exst!(NatLiteral(33))])),
+  ] }
+)
+  }
+}

schala-lang/language/src/prelude.schala

@@ -1,3 +1,4 @@
+let _SCHALA_VERSION = "0.1.0"
 
 type Option<T> = Some(T) | None
 type Ord = LT | EQ | GT
@@ -5,10 +6,9 @@ type Ord = LT | EQ | GT
 
 fn map(input: Option<T>, func: Func): Option<T> {
   if input {
-    is Option::Some(x) -> Option::Some(func(x)),
-    is Option::None -> Option::None,
+    is Option::Some(x) then Option::Some(func(x)),
+    is Option::None then Option::None,
   }
 }
 
-
 type Complicated = Sunrise | Metal { black: bool, norwegian: bool } | Fella(String, Int)

schala-lang/language/src/reduced_ast.rs

@@ -18,6 +18,7 @@ use std::str::FromStr;
 use crate::ast::*;
 use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable, FullyQualifiedSymbolName};
 use crate::builtin::Builtin;
+use crate::util::deref_optional_box;
 
 #[derive(Debug)]
 pub struct ReducedAST(pub Vec<Stmt>);
@@ -41,9 +42,9 @@ pub enum Stmt {
 pub enum Expr {
   Unit,
   Lit(Lit),
+  Sym(Rc<String>), //a Sym is anything that can be looked up by name at runtime - i.e. a function or variable address
   Tuple(Vec<Expr>),
   Func(Func),
-  Sym(Rc<String>),
   Constructor {
     type_name: Rc<String>,
     name: Rc<String>,
@@ -55,7 +56,7 @@ pub enum Expr {
     args: Vec<Expr>,
   },
   Assign {
-    val: Box<Expr>,
+    val: Box<Expr>, //TODO this probably can't be a val
     expr: Box<Expr>,
   },
   Conditional {
@@ -129,6 +130,13 @@ impl<'a> Reducer<'a> {
     match &stmt.kind {
       StatementKind::Expression(expr) => Stmt::Expr(self.expression(&expr)),
       StatementKind::Declaration(decl) => self.declaration(&decl),
+      StatementKind::Import(_) => Stmt::Noop,
+      StatementKind::Module(modspec) => {
+        for statement in modspec.contents.iter() {
+          self.statement(&statement);
+        }
+        Stmt::Noop
+      }
     }
   }
 
@@ -156,28 +164,10 @@ impl<'a> Reducer<'a> {
       BoolLiteral(b) => Expr::Lit(Lit::Bool(*b)),
       BinExp(binop, lhs, rhs) => self.binop(binop, lhs, rhs),
       PrefixExp(op, arg) => self.prefix(op, arg),
-      Value(qualified_name) => {
-        let ref id = qualified_name.id;
-        let ref sym_name = match symbol_table.get_fqsn_from_id(id) {
-          Some(fqsn) => fqsn,
-          None => return Expr::ReductionError(format!("FQSN lookup for Value {:?} failed", qualified_name)),
-        };
-        //TODO this probably needs to change
-        let FullyQualifiedSymbolName(ref v) = sym_name;
-        let name = v.last().unwrap().name.clone();
-        match symbol_table.lookup_by_fqsn(&sym_name) {
-          Some(Symbol { spec: SymbolSpec::DataConstructor { index, type_args, type_name}, .. }) => Expr::Constructor {
-            type_name: type_name.clone(),
-            name: name.clone(),
-            tag: index.clone(),
-            arity: type_args.len(),
-          },
-          _ => Expr::Sym(name.clone()),
-        }
-      },
+      Value(qualified_name) => self.value(qualified_name),
       Call { f, arguments } =>  self.reduce_call_expression(f, arguments),
       TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| self.expression(e)).collect()),
-      IfExpression { discriminator, body } => self.reduce_if_expression(discriminator, body),
+      IfExpression { discriminator, body } => self.reduce_if_expression(deref_optional_box(discriminator), body),
       Lambda { params, body, .. } => self.reduce_lambda(params, body),
       NamedStruct { name, fields } => self.reduce_named_struct(name, fields),
       Index { .. } => Expr::UnimplementedSigilValue,
@@ -187,6 +177,38 @@ impl<'a> Reducer<'a> {
     }
   }
 
+  fn value(&mut self, qualified_name: &QualifiedName) -> Expr {
+    let symbol_table = self.symbol_table;
+    let ref id = qualified_name.id;
+    let ref sym_name = match symbol_table.get_fqsn_from_id(id) {
+      Some(fqsn) => fqsn,
+      None => return Expr::ReductionError(format!("FQSN lookup for Value {:?} failed", qualified_name)),
+    };
+
+    //TODO this probably needs to change
+    let FullyQualifiedSymbolName(ref v) = sym_name;
+    let name = v.last().unwrap().name.clone();
+
+    let Symbol { local_name, spec, .. } = match symbol_table.lookup_by_fqsn(&sym_name) {
+      Some(s) => s,
+      //None => return Expr::ReductionError(format!("Symbol {:?} not found", sym_name)),
+      None => return Expr::Sym(name.clone())
+    };
+
+    match spec {
+      SymbolSpec::RecordConstructor { .. } => Expr::ReductionError(format!("AST reducer doesn't expect a RecordConstructor here")),
+      SymbolSpec::DataConstructor { index, type_args, type_name } => Expr::Constructor {
+        type_name: type_name.clone(),
+        name: name.clone(),
+        tag: index.clone(),
+        arity: type_args.len(),
+      },
+      SymbolSpec::Func(_) => Expr::Sym(local_name.clone()),
+      SymbolSpec::Binding => Expr::Sym(local_name.clone()), //TODO not sure if this is right, probably needs to eventually be fqsn
+      SymbolSpec::Type { .. } => Expr::ReductionError("AST reducer doesnt expect a type here".to_string())
+    }
+  }
+
   fn reduce_lambda(&mut self, params: &Vec<FormalParam>, body: &Block) -> Expr {
     Expr::Func(Func::UserDefined {
       name: None,
@@ -231,30 +253,31 @@ impl<'a> Reducer<'a> {
     }
   }
 
-  fn reduce_if_expression(&mut self, discriminator: &Discriminator, body: &IfExpressionBody) -> Expr {
+  fn reduce_if_expression(&mut self, discriminator: Option<&Expression>, body: &IfExpressionBody) -> Expr {
     let symbol_table = self.symbol_table;
-    let cond = Box::new(match *discriminator {
-      Discriminator::Simple(ref expr) => self.expression(expr),
-      Discriminator::BinOp(ref _expr, ref _binop) => panic!("Can't yet handle binop discriminators")
+    let cond = Box::new(match discriminator {
+      Some(expr) => self.expression(expr),
+      None => return Expr::ReductionError(format!("blank cond if-expr not supported")),
     });
-    match *body {
-      IfExpressionBody::SimpleConditional(ref then_clause, ref else_clause) => {
-        let then_clause = self.block(then_clause);
-        let else_clause = match else_clause {
+
+    match body {
+      IfExpressionBody::SimpleConditional { then_case, else_case } => {
+        let then_clause = self.block(&then_case);
+        let else_clause = match else_case.as_ref() {
           None => vec![],
-          Some(stmts) => self.block(stmts),
+          Some(stmts) => self.block(&stmts),
         };
         Expr::Conditional { cond, then_clause, else_clause }
       },
-      IfExpressionBody::SimplePatternMatch(ref pat, ref then_clause, ref else_clause) => {
-        let then_clause = self.block(then_clause);
-        let else_clause = match else_clause {
+      IfExpressionBody::SimplePatternMatch { pattern, then_case, else_case } => {
+        let then_clause = self.block(&then_case);
+        let else_clause = match else_case.as_ref() {
           None => vec![],
-          Some(stmts) => self.block(stmts),
+          Some(stmts) => self.block(&stmts),
         };
 
         let alternatives = vec![
-          pat.to_alternative(then_clause, symbol_table),
+          pattern.to_alternative(then_clause, symbol_table),
           Alternative {
             matchable: Subpattern {
               tag: None,
@@ -271,16 +294,22 @@ impl<'a> Reducer<'a> {
           alternatives,
         }
       },
-      IfExpressionBody::GuardList(ref guard_arms) => {
+      IfExpressionBody::CondList(ref condition_arms) => {
         let mut alternatives = vec![];
-        for arm in guard_arms {
-          match arm.guard {
-            Guard::Pat(ref p) =>  {
+        for arm in condition_arms {
+          match arm.condition {
+            Condition::Expression(ref _expr) => {
+              return Expr::UnimplementedSigilValue
+            },
+            Condition::Pattern(ref p) =>  {
               let item = self.block(&arm.body);
               let alt = p.to_alternative(item, symbol_table);
               alternatives.push(alt);
             },
-            Guard::HalfExpr(HalfExpr { op: _, expr: _ }) => {
+            Condition::TruncatedOp(_, _) => {
+              return Expr::UnimplementedSigilValue
+            },
+            Condition::Else => {
               return Expr::UnimplementedSigilValue
             }
           }
@@ -333,7 +362,7 @@ impl<'a> Reducer<'a> {
         }
       },
       TypeDecl { .. } => Stmt::Noop,
-      TypeAlias(_, _) => Stmt::Noop,
+      TypeAlias{ .. } => Stmt::Noop,
       Interface { .. } => Stmt::Noop,
       Impl { .. } => Stmt::Expr(Expr::UnimplementedSigilValue),
       _ => Stmt::Expr(Expr::UnimplementedSigilValue)
@@ -435,7 +464,6 @@ impl Pattern {
       VarOrName(QualifiedName { components, id  }) => {
         // if fqsn is Some, treat this as a symbol pattern. If it's None, treat it
         // as a variable.
-        println!("Calling VarOrName reduction with : {:?}", components);
         let fqsn = symbol_table.get_fqsn_from_id(&id);
         match fqsn.and_then(|fqsn| symbol_table.lookup_by_fqsn(&fqsn)) {
           Some(symbol) => handle_symbol(Some(symbol), &vec![], symbol_table),

schala-lang/language/src/schala.rs

@@ -10,17 +10,22 @@ use schala_repl::{ProgrammingLanguageInterface,
 ComputationRequest, ComputationResponse,
 LangMetaRequest, LangMetaResponse, GlobalOutputStats,
 DebugResponse, DebugAsk};
-use crate::{ast, reduced_ast, tokenizing, parsing, eval, typechecking, symbol_table};
+use crate::{ast, reduced_ast, tokenizing, parsing, eval, typechecking, symbol_table, source_map};
+
+pub type SymbolTableHandle = Rc<RefCell<symbol_table::SymbolTable>>;
+pub type SourceMapHandle = Rc<RefCell<source_map::SourceMap>>;
 
 /// All the state necessary to parse and execute a Schala program are stored in this struct.
 /// `state` represents the execution state for the AST-walking interpreter, the other fields
 /// should be self-explanatory.
 pub struct Schala {
   source_reference: SourceReference,
+  source_map: SourceMapHandle,
   state: eval::State<'static>,
-  symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
+  symbol_table: SymbolTableHandle,
+  resolver: crate::scope_resolution::ScopeResolver<'static>,
   type_context: typechecking::TypeContext<'static>,
-  active_parser: Option<parsing::Parser>,
+  active_parser: parsing::Parser,
 }
 
 impl Schala {
@@ -34,13 +39,17 @@ impl Schala {
 impl Schala {
   /// Creates a new Schala environment *without* any prelude.
   fn new_blank_env() -> Schala {
-    let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new()));
+    let source_map = Rc::new(RefCell::new(source_map::SourceMap::new()));
+    let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new(source_map.clone())));
     Schala {
+      //TODO maybe these can be the same structure
       source_reference: SourceReference::new(),
       symbol_table: symbols.clone(),
-      state: eval::State::new(symbols),
+      source_map: source_map.clone(),
+      resolver: crate::scope_resolution::ScopeResolver::new(symbols.clone()),
+      state: eval::State::new(),
       type_context: typechecking::TypeContext::new(),
-      active_parser: None,
+      active_parser: parsing::Parser::new(source_map)
     }
   }
 
@@ -51,7 +60,10 @@ impl Schala {
     let mut s = Schala::new_blank_env();
 
     let request = ComputationRequest { source: prelude, debug_requests: HashSet::default() };
-    s.run_computation(request);
+    let response = s.run_computation(request);
+    if let Err(msg) = response.main_output {
+      panic!("Error in prelude, panicking: {}", msg);
+    }
     s
   }
 
@@ -94,10 +106,10 @@ fn tokenizing(input: &str, _handle: &mut Schala, comp: Option<&mut PassDebugArti
 }
 
 fn parsing(input: Vec<tokenizing::Token>, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
-  use crate::parsing::Parser;
   use ParsingDebugType::*;
 
-  let mut parser = handle.active_parser.take().unwrap_or_else(|| Parser::new(input));
+  let ref mut parser = handle.active_parser;
+  parser.add_new_tokens(input);
   let ast = parser.parse();
 
   comp.map(|comp| {
@@ -115,24 +127,30 @@ fn parsing(input: Vec<tokenizing::Token>, handle: &mut Schala, comp: Option<&mut
     };
     comp.add_artifact(debug_info);
   });
-  ast.map_err(|err| format_parse_error(err, handle))
+  ast.map_err(|err| format_parse_error(err, &handle.source_reference))
 }
 
-fn format_parse_error(error: parsing::ParseError, handle: &mut Schala) -> String {
-  let line_num = error.token.line_num;
-  let ch = error.token.char_num;
-  let line_from_program = handle.source_reference.get_line(line_num);
+fn format_parse_error(error: parsing::ParseError, source_reference: &SourceReference) -> String {
+  let line_num = error.token.location.line_num;
+  let ch = error.token.location.char_num;
+  let line_from_program = source_reference.get_line(line_num);
   let location_pointer = format!("{}^", " ".repeat(ch));
 
   let line_num_digits = format!("{}", line_num).chars().count();
   let space_padding = " ".repeat(line_num_digits);
 
+  let production = match error.production_name {
+    Some(n) => format!("\n(from production \"{}\")", n),
+    None => "".to_string()
+  };
+
   format!(r#"
-{error_msg}
+{error_msg}{production}
 {space_padding} |
 {line_num} | {}
 {space_padding} | {}
-"#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num)
+"#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num, production=production
+)
 }
 
 fn symbol_table(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
@@ -145,9 +163,7 @@ fn symbol_table(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebu
 }
 
 fn scope_resolution(mut input: ast::AST, handle: &mut Schala, _com: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
-  let mut symbol_table = handle.symbol_table.borrow_mut();
-  let mut resolver = crate::scope_resolution::ScopeResolver::new(&mut symbol_table);
-  let () = resolver.resolve(&mut input)?;
+  let () = handle.resolver.resolve(&mut input)?;
   Ok(input)
 }
 

schala-lang/language/src/scope_resolution.rs

@@ -1,173 +1,115 @@
-use crate::symbol_table::{SymbolTable, ScopeSegment, ScopeSegmentKind, FullyQualifiedSymbolName};
+use std::rc::Rc;
+
+use crate::schala::SymbolTableHandle;
+use crate::symbol_table::{ScopeSegment, FullyQualifiedSymbolName};
 use crate::ast::*;
+use crate::util::ScopeStack;
+
+type FQSNPrefix = Vec<ScopeSegment>;
 
 pub struct ScopeResolver<'a> {
-  symbol_table: &'a mut SymbolTable
+  symbol_table_handle: SymbolTableHandle,
+  name_scope_stack: ScopeStack<'a, Rc<String>, FQSNPrefix>,
 }
 
-impl<'a> ScopeResolver<'a> {
-  pub fn new(symbol_table: &'a mut SymbolTable) -> ScopeResolver {
-    ScopeResolver { symbol_table }
-  }
-  pub fn resolve(&mut self, ast: &mut AST) -> Result<(), String> {
-    for statement in ast.statements.iter() {
-      match statement.kind {
-        StatementKind::Declaration(ref decl) => self.decl(decl),
-        StatementKind::Expression(ref expr) => self.expr(expr),
-      }?;
-    }
-    Ok(())
-  }
-
-  fn decl(&mut self, decl: &Declaration) -> Result<(), String> {
-    use Declaration::*;
-    match decl {
-      Binding { expr, .. } => self.expr(expr),
-      FuncDecl(_, block) => self.block(block),
-      _ => Ok(()),
-    }
-  }
-  fn block(&mut self, block: &Block) -> Result<(), String> {
-    for statement in block.iter() {
-      match statement.kind {
-        StatementKind::Declaration(ref decl) => self.decl(decl),
-        StatementKind::Expression(ref expr) => self.expr(expr),
-      }?;
-    }
-    Ok(())
-  }
-
-  fn expr(&mut self, expr: &Expression) -> Result<(), String> {
-    use ExpressionKind::*;
-    match &expr.kind {
-      ExpressionKind::Value(qualified_name) => {
-        let fqsn = lookup_name_in_scope(&qualified_name);
-        let ref id = qualified_name.id;
-        self.symbol_table.map_id_to_fqsn(id, fqsn);
-      },
-      NamedStruct {  name, .. } => {
-        let ref id = name.id;
-        let fqsn = lookup_name_in_scope(&name);
-        self.symbol_table.map_id_to_fqsn(id, fqsn);
-      },
-      BinExp(_, ref lhs, ref rhs) => {
-        self.expr(lhs)?;
-        self.expr(rhs)?;
-      },
-      PrefixExp(_, ref arg) => {
-        self.expr(arg)?;
-      },
-      TupleLiteral(exprs) => {
-        for expr in exprs.iter() {
-          self.expr(expr)?;
+impl<'a> ASTVisitor for ScopeResolver<'a> {
+  //TODO need to un-insert these - maybe need to rethink visitor
+  fn import(&mut self, import_spec: &ImportSpecifier) {
+    let ref symbol_table = self.symbol_table_handle.borrow();
+    let ImportSpecifier { ref path_components, ref imported_names, .. } = &import_spec;
+    match imported_names {
+      ImportedNames::All => {
+        let prefix = FullyQualifiedSymbolName(path_components.iter().map(|c| ScopeSegment {
+          name: c.clone(),
+        }).collect());
+        let members = symbol_table.lookup_children_of_fqsn(&prefix);
+        for member in members.into_iter() {
+          let local_name = member.0.last().unwrap().name.clone();
+          self.name_scope_stack.insert(local_name.clone(), member.0);
         }
       },
-      Call { f, arguments } => {
-        self.expr(&f)?;
-        for arg in arguments.iter() {
-          self.invoc(arg)?;
+      ImportedNames::LastOfPath => {
+        let name = path_components.last().unwrap(); //TODO handle better
+        let fqsn_prefix = path_components.iter().map(|c| ScopeSegment {
+          name: c.clone(),
+        }).collect();
+        self.name_scope_stack.insert(name.clone(), fqsn_prefix);
+      }
+      ImportedNames::List(ref names) => {
+        let fqsn_prefix: FQSNPrefix = path_components.iter().map(|c| ScopeSegment {
+          name: c.clone(),
+        }).collect();
+        for name in names.iter() {
+          self.name_scope_stack.insert(name.clone(), fqsn_prefix.clone());
         }
-      },
-      Lambda { params, body, .. } => { 
-        self.block(&body)?;
-        for param in params.iter() {
-          if let Some(ref expr) = param.default {
-            self.expr(expr)?;
-          }
-        }
-      },
-      IfExpression { ref body, ref discriminator } => {
-        match &**discriminator {
-          Discriminator::Simple(expr) | Discriminator::BinOp(expr, _) => self.expr(expr)?
-        };
-
-        match &**body {
-          IfExpressionBody::SimplePatternMatch(ref pat, ref alt1, ref alt2) => {
-            self.pattern(pat)?;
-            self.block(alt1)?;
-            if let Some(alt) = alt2 {
-              self.block(alt)?;
-            }
-          },
-          IfExpressionBody::GuardList(guardarms) => {
-            for arm in guardarms.iter() {
-              if let Guard::Pat(ref pat) = arm.guard {
-                self.pattern(pat)?;
-              }
-              self.block(&arm.body)?;
-            }
-          }
-          _ => ()
-        }
-      },
-      _ => ()
+      }
     };
-    Ok(())
   }
 
-  fn invoc(&mut self, invoc: &InvocationArgument) -> Result<(), String> {
-    use InvocationArgument::*;
-    match invoc {
-      Positional(expr) => self.expr(expr),
-      Keyword { expr, .. } => self.expr(expr),
-      _ => Ok(())
-    }
+  fn qualified_name(&mut self, qualified_name: &QualifiedName) {
+    let ref mut symbol_table = self.symbol_table_handle.borrow_mut();
+    let fqsn = self.lookup_name_in_scope(&qualified_name);
+    let ref id = qualified_name.id;
+    symbol_table.map_id_to_fqsn(id, fqsn);
   }
 
-  fn pattern(&mut self, pat: &Pattern) -> Result<(), String> {
+  fn named_struct(&mut self, name: &QualifiedName, _fields: &Vec<(Rc<String>, Expression)>) {
+    let ref mut symbol_table = self.symbol_table_handle.borrow_mut();
+    let ref id = name.id;
+    let fqsn = self.lookup_name_in_scope(&name);
+    symbol_table.map_id_to_fqsn(id, fqsn);
+  }
+
+  fn pattern(&mut self, pat: &Pattern) {
     use Pattern::*;
     match pat {
       Ignored => (),
-      TuplePattern(patterns) => {
-        for pat in patterns {
-          self.pattern(pat)?;
-        }
-      },
+      TuplePattern(_) => (),
       Literal(_) => (),
-      TupleStruct(name, patterns) => {
-        self.qualified_name_in_pattern(name);
-        for pat in patterns {
-          self.pattern(pat)?;
-        }
-      },
-      Record(name, key_patterns) => {
-        self.qualified_name_in_pattern(name);
-        for (_, pat) in key_patterns {
-          self.pattern(pat)?;
-        }
-      },
-      VarOrName(name) => {
-        self.qualified_name_in_pattern(name);
-      },
+      TupleStruct(name, _) => self.qualified_name_in_pattern(name),
+      Record(name, _) => self.qualified_name_in_pattern(name),
+      VarOrName(name) => self.qualified_name_in_pattern(name),
     };
+  }
+}
+
+impl<'a> ScopeResolver<'a> {
+  pub fn new(symbol_table_handle: SymbolTableHandle) -> ScopeResolver<'static> {
+    let name_scope_stack = ScopeStack::new(None);
+    ScopeResolver { symbol_table_handle, name_scope_stack }
+  }
+  pub fn resolve(&mut self, ast: &mut AST) -> Result<(), String> {
+    walk_ast(self, ast);
     Ok(())
   }
 
+  fn lookup_name_in_scope(&self, sym_name: &QualifiedName) -> FullyQualifiedSymbolName {
+    let QualifiedName { components, .. } = sym_name;
+    let first_component = &components[0];
+    match self.name_scope_stack.lookup(first_component) {
+      None => {
+        FullyQualifiedSymbolName(components.iter().map(|name| ScopeSegment { name: name.clone() }).collect())
+      },
+      Some(fqsn_prefix) => {
+        let mut full_name = fqsn_prefix.clone();
+        let rest_of_name: FQSNPrefix = components[1..].iter().map(|name| ScopeSegment { name: name.clone() }).collect();
+        full_name.extend_from_slice(&rest_of_name);
+        FullyQualifiedSymbolName(full_name)
+      }
+    }
+  }
+
   /// this might be a variable or a pattern. if a variable, set to none
   fn qualified_name_in_pattern(&mut self, qualified_name: &QualifiedName) {
+    let ref mut symbol_table = self.symbol_table_handle.borrow_mut();
     let ref id = qualified_name.id;
-    let fqsn = lookup_name_in_scope(qualified_name);
-    if self.symbol_table.lookup_by_fqsn(&fqsn).is_some() {
-      self.symbol_table.map_id_to_fqsn(&id, fqsn);
+    let fqsn = self.lookup_name_in_scope(qualified_name);
+    if symbol_table.lookup_by_fqsn(&fqsn).is_some() {
+      symbol_table.map_id_to_fqsn(&id, fqsn);
     }
   }
 }
 
-//TODO this is incomplete
-fn lookup_name_in_scope(sym_name: &QualifiedName) -> FullyQualifiedSymbolName {
-  let QualifiedName { components: vec, .. } = sym_name;
-  let len = vec.len();
-  let new_vec: Vec<ScopeSegment> = vec.iter().enumerate().map(|(i, name)| {
-    let kind = if i == (len - 1) {
-      ScopeSegmentKind::Terminal
-    } else {
-      ScopeSegmentKind::Type
-    };
-    ScopeSegment { name: name.clone(), kind }
-  }).collect();
-   FullyQualifiedSymbolName(new_vec)
-}
-
 #[cfg(test)]
 mod tests {
   #[test]

schala-lang/language/src/source_map.rs

@@ -0,0 +1,39 @@
+use std::collections::HashMap;
+use std::fmt;
+
+use crate::ast::ItemId;
+
+pub type LineNumber = usize;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Location {
+  pub line_num: LineNumber,
+  pub char_num: usize,
+}
+
+impl fmt::Display for Location {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    write!(f, "{}:{}", self.line_num, self.char_num)
+  }
+}
+
+pub struct SourceMap {
+  map: HashMap<ItemId, Location>
+}
+
+impl SourceMap {
+  pub fn new() -> SourceMap {
+    SourceMap { map: HashMap::new() }
+  }
+
+  pub fn add_location(&mut self, id: &ItemId, loc: Location) {
+    self.map.insert(id.clone(), loc);
+  }
+
+  pub fn lookup(&self, id: &ItemId) -> Option<Location> {
+    match self.map.get(id) {
+      Some(loc) => Some(loc.clone()),
+      None => None
+    }
+  }
+}

schala-lang/language/src/symbol_table.rs

@@ -4,14 +4,61 @@ use std::rc::Rc;
 use std::fmt;
 use std::fmt::Write;
 
+use crate::schala::SourceMapHandle;
+use crate::source_map::{SourceMap, LineNumber};
 use crate::ast;
-use crate::ast::{ItemId, TypeBody, TypeSingletonName, Signature, Statement, StatementKind};
+use crate::ast::{ItemId, TypeBody, TypeSingletonName, Signature, Statement, StatementKind, ModuleSpecifier};
 use crate::typechecking::TypeName;
 
-type LineNumber = u32;
-type SymbolTrackTable = HashMap<Rc<String>, LineNumber>;
 
-#[derive(PartialEq, Eq, Hash, Debug, Clone)]
+#[allow(unused_macros)]
+macro_rules! fqsn {
+  ( $( $name:expr ; $kind:tt),* ) => {
+    {
+      let mut vec = vec![];
+      $(
+        vec.push(crate::symbol_table::ScopeSegment::new(std::rc::Rc::new($name.to_string())));
+      )*
+      FullyQualifiedSymbolName(vec)
+    }
+  };
+}
+
+mod symbol_trie;
+use symbol_trie::SymbolTrie;
+mod test;
+
+/// Keeps track of what names were used in a given namespace. Call try_register to add a name to
+/// the table, or report an error if a name already exists.
+struct DuplicateNameTrackTable {
+  table: HashMap<Rc<String>, LineNumber>,
+}
+
+impl DuplicateNameTrackTable {
+  fn new() -> DuplicateNameTrackTable {
+    DuplicateNameTrackTable { table: HashMap::new() }
+  }
+
+  fn try_register(&mut self, name: &Rc<String>, id: &ItemId, source_map: &SourceMap) -> Result<(), LineNumber> {
+    match self.table.entry(name.clone()) {
+      Entry::Occupied(o) => {
+        let line_number = o.get();
+        Err(*line_number)
+      },
+      Entry::Vacant(v) => {
+        let line_number = if let Some(loc) = source_map.lookup(id) {
+          loc.line_num
+        } else {
+          0
+        };
+        v.insert(line_number);
+        Ok(())
+      }
+    }
+  }
+}
+
+#[derive(PartialEq, Eq, Hash, Debug, Clone, PartialOrd, Ord)]
 pub struct FullyQualifiedSymbolName(pub Vec<ScopeSegment>);
 
 impl fmt::Display for FullyQualifiedSymbolName {
@@ -24,72 +71,40 @@ impl fmt::Display for FullyQualifiedSymbolName {
   }
 }
 
-#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
 pub struct ScopeSegment {
   pub name: Rc<String>, //TODO maybe this could be a &str, for efficiency?
-  pub kind: ScopeSegmentKind,
 }
 
 impl fmt::Display for ScopeSegment {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    use ScopeSegmentKind::*;
-    let kind = match self.kind {
-      Function => "fn",
-      Type => "ty",
-      Terminal => "tr",
-    };
-    write!(f, "{}({})", self.name, kind)
+    let kind = ""; //TODO implement some kind of kind-tracking here
+    write!(f, "{}{}", self.name, kind)
   }
 }
 
 impl ScopeSegment {
-  pub fn new(name: Rc<String>, kind: ScopeSegmentKind) ->  ScopeSegment {
-    ScopeSegment { name, kind }
+  pub fn new(name: Rc<String>) ->  ScopeSegment {
+    ScopeSegment { name }
   }
 }
 
-#[derive(Debug, Clone, Eq, PartialEq, Hash)]
-pub enum ScopeSegmentKind {
-  Function,
-  Type,
-  Terminal,
-}
-
-#[allow(unused_macros)]
-macro_rules! fqsn {
-  ( $( $name:expr ; $kind:tt),* ) => {
-    {
-      let mut vec = vec![];
-      $(
-        vec.push(ScopeSegment::new(
-            Rc::new($name.to_string()),  
-            sym_path_kind!($kind),
-        ));
-      )*
-      FullyQualifiedSymbolName(vec)
-    }
-  };
-}
-
-#[allow(unused_macros)]
-macro_rules! sym_path_kind {
-  (fn) => { ScopeSegmentKind::Function };
-  (ty) => { ScopeSegmentKind::Type };
-  (tr) => { ScopeSegmentKind::Terminal };
-}
 
 //cf. p. 150 or so of Language Implementation Patterns
 pub struct SymbolTable {
+  source_map_handle: SourceMapHandle,
   symbol_path_to_symbol: HashMap<FullyQualifiedSymbolName, Symbol>,
   id_to_fqsn: HashMap<ItemId, FullyQualifiedSymbolName>,
+  symbol_trie: SymbolTrie,
 }
 
-//TODO add various types of lookups here, maybe multiple hash tables internally?
 impl SymbolTable {
-  pub fn new() -> SymbolTable {
+  pub fn new(source_map_handle: SourceMapHandle) -> SymbolTable {
     SymbolTable {
+      source_map_handle,
       symbol_path_to_symbol: HashMap::new(),
       id_to_fqsn: HashMap::new(),
+      symbol_trie: SymbolTrie::new()
     }
   }
 
@@ -101,29 +116,34 @@ impl SymbolTable {
     self.id_to_fqsn.get(&id).cloned()
   }
 
-  fn add_new_symbol(&mut self, name: &Rc<String>, scope_path: &Vec<ScopeSegment>, spec: SymbolSpec) {
+  fn add_new_symbol(&mut self, local_name: &Rc<String>, scope_path: &Vec<ScopeSegment>, spec: SymbolSpec) {
     let mut vec: Vec<ScopeSegment> = scope_path.clone();
-    vec.push(ScopeSegment { name: name.clone(), kind: ScopeSegmentKind::Terminal });
+    vec.push(ScopeSegment { name: local_name.clone() });
     let fully_qualified_name = FullyQualifiedSymbolName(vec);
-    let symbol = Symbol { name: name.clone(), fully_qualified_name: fully_qualified_name.clone(), spec };
+    let symbol = Symbol { local_name: local_name.clone(), fully_qualified_name: fully_qualified_name.clone(), spec };
+    self.symbol_trie.insert(&fully_qualified_name);
     self.symbol_path_to_symbol.insert(fully_qualified_name, symbol);
   }
 
   pub fn lookup_by_fqsn(&self, fully_qualified_path: &FullyQualifiedSymbolName) -> Option<&Symbol> {
     self.symbol_path_to_symbol.get(fully_qualified_path)
   }
+
+  pub fn lookup_children_of_fqsn(&self, path: &FullyQualifiedSymbolName) -> Vec<FullyQualifiedSymbolName> {
+    self.symbol_trie.get_children(path)
+  }
 }
 
 #[derive(Debug)]
 pub struct Symbol {
-  pub name: Rc<String>, //TODO does this need to be pub?
+  pub local_name: Rc<String>, //TODO does this need to be pub?
   fully_qualified_name: FullyQualifiedSymbolName,
   pub spec: SymbolSpec,
 }
 
 impl fmt::Display for Symbol {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    write!(f, "<Name: {}, Spec: {}>", self.name, self.spec)
+    write!(f, "<Local name: {}, Spec: {}>", self.local_name, self.spec)
   }
 }
 
@@ -140,7 +160,10 @@ pub enum SymbolSpec {
     members: HashMap<Rc<String>, TypeName>,
     type_name: TypeName,
   },
-  Binding
+  Binding,
+  Type {
+    name: TypeName
+  },
 }
 
 impl fmt::Display for SymbolSpec {
@@ -151,6 +174,7 @@ impl fmt::Display for SymbolSpec {
       DataConstructor { index, type_name, type_args } => write!(f, "DataConstructor(idx: {})({:?} -> {})", index, type_args, type_name),
       RecordConstructor { type_name, index, ..} => write!(f, "RecordConstructor(idx: {})(<members> -> {})", index, type_name),
       Binding => write!(f, "Binding"),
+      Type { name } => write!(f, "Type <{}>", name),
     }
   }
 }
@@ -167,58 +191,60 @@ impl SymbolTable {
   fn add_symbols_from_scope<'a>(&'a mut self, statements: &Vec<Statement>, scope_name_stack: &mut Vec<ScopeSegment>) -> Result<(), String> {
     use self::ast::Declaration::*;
 
-    fn insert_and_check_duplicate_symbol(table: &mut SymbolTrackTable, name: &Rc<String>) -> Result<(), String> {
-      match table.entry(name.clone()) {
-        Entry::Occupied(o) => {
-          let line_number = o.get(); //TODO make this actually work
-          Err(format!("Duplicate definition: {}. It's already defined at {}", name, line_number))
-        },
-        Entry::Vacant(v) => {
-          let line_number = 0; //TODO should work
-          v.insert(line_number);
-          Ok(())
-        }
-      }
-    }
-
-    let mut seen_identifiers: SymbolTrackTable = HashMap::new();
+    let mut seen_identifiers = DuplicateNameTrackTable::new();
+    let mut seen_modules = DuplicateNameTrackTable::new();
 
     for statement in statements.iter() {
-      if let Statement { kind: StatementKind::Declaration(decl), .. } = statement {
-        match decl {
-          FuncSig(ref signature) => {
-            insert_and_check_duplicate_symbol(&mut seen_identifiers, &signature.name)?;
-            self.add_function_signature(signature, scope_name_stack)?
+      match statement {
+        Statement { kind: StatementKind::Declaration(decl), id } => {
+          match decl {
+            FuncSig(ref signature) => {
+              seen_identifiers.try_register(&signature.name, &id, &self.source_map_handle.borrow())
+                .map_err(|line| format!("Duplicate function definition: {}. It's already defined at {}", signature.name, line))?;
+              self.add_function_signature(signature, scope_name_stack)?
+            }
+            FuncDecl(ref signature, ref body) => {
+              seen_identifiers.try_register(&signature.name, &id, &self.source_map_handle.borrow())
+                .map_err(|line| format!("Duplicate function definition: {}. It's already defined at {}", signature.name, line))?;
+              self.add_function_signature(signature, scope_name_stack)?;
+              scope_name_stack.push(ScopeSegment{
+                name: signature.name.clone(),
+              });
+              let output = self.add_symbols_from_scope(body, scope_name_stack);
+              scope_name_stack.pop();
+              output?
+            },
+            TypeDecl { name, body, mutable } => {
+              seen_identifiers.try_register(&name.name, &id, &self.source_map_handle.borrow())
+                .map_err(|line| format!("Duplicate type definition: {}. It's already defined at {}", name.name, line))?;
+              self.add_type_decl(name, body, mutable, scope_name_stack)?
+            },
+            Binding { name, .. } => {
+              seen_identifiers.try_register(&name, &id, &self.source_map_handle.borrow())
+                .map_err(|line| format!("Duplicate variable definition: {}. It's already defined at {}", name, line))?;
+              self.add_new_symbol(name, scope_name_stack, SymbolSpec::Binding);
+            }
+            _ => ()
           }
-          FuncDecl(ref signature, ref body) => {
-            insert_and_check_duplicate_symbol(&mut seen_identifiers, &signature.name)?;
-            self.add_function_signature(signature, scope_name_stack)?;
-            scope_name_stack.push(ScopeSegment{
-              name: signature.name.clone(),
-              kind: ScopeSegmentKind::Function,
-            });
-            let output = self.add_symbols_from_scope(body, scope_name_stack);
-            let _ = scope_name_stack.pop();
-            output?
-          },
-          TypeDecl { name, body, mutable } => {
-            insert_and_check_duplicate_symbol(&mut seen_identifiers, &name.name)?;
-            //TODO add ScopeSegmentKind::Type here
-            self.add_type_decl(name, body, mutable, scope_name_stack)?
-          },
-          Binding { name, .. } => {
-            insert_and_check_duplicate_symbol(&mut seen_identifiers, name)?;
-            self.add_new_symbol(name, scope_name_stack, SymbolSpec::Binding);
-          }
-          _ => ()
-        }
+        },
+        Statement { kind: StatementKind::Module(ModuleSpecifier { name, contents}), id } => {
+          seen_modules.try_register(&name, &id, &self.source_map_handle.borrow())
+            .map_err(|line| format!("Duplicate module definition: {}. It's already defined at {}", name, line))?;
+          scope_name_stack.push(ScopeSegment { name: name.clone() });
+          let output = self.add_symbols_from_scope(contents, scope_name_stack);
+          scope_name_stack.pop();
+          output?
+        },
+        _ => ()
       }
     }
     Ok(())
   }
   pub fn debug_symbol_table(&self) -> String {
     let mut output = format!("Symbol table\n");
-    for (name, sym) in &self.symbol_path_to_symbol {
+    let mut sorted_symbols: Vec<(&FullyQualifiedSymbolName, &Symbol)> = self.symbol_path_to_symbol.iter().collect();
+    sorted_symbols.sort_by(|(fqsn, _), (other_fqsn, _)| fqsn.cmp(other_fqsn));
+    for (name, sym) in sorted_symbols.iter() {
       write!(output, "{} -> {}\n", name, sym).unwrap();
     }
     output
@@ -239,9 +265,15 @@ impl SymbolTable {
     use crate::ast::{TypeIdentifier, Variant};
     let TypeBody(variants) = body;
     let ref type_name = type_name.name;
+
+
+    let type_spec = SymbolSpec::Type {
+      name: type_name.clone(),
+    };
+    self.add_new_symbol(type_name, &scope_name_stack, type_spec);
+
     scope_name_stack.push(ScopeSegment{
       name: type_name.clone(),
-      kind: ScopeSegmentKind::Type,
     });
     //TODO figure out why _params isn't being used here
     for (index, var) in variants.iter().enumerate() {
@@ -309,156 +341,3 @@ impl LocalTypeContext {
   }
 }
 
-
-#[cfg(test)]
-mod symbol_table_tests {
-  use super::*;
-  use crate::util::quick_ast;
-
-  macro_rules! values_in_table {
-    //TODO multiple values
-    ($source:expr, $single_value:expr) => {
-      {
-      let mut symbol_table = SymbolTable::new();
-      let ast = quick_ast($source);
-      symbol_table.add_top_level_symbols(&ast).unwrap();
-      match symbol_table.lookup_by_fqsn($single_value) {
-        Some(_spec) => (),
-        None => panic!(),
-      };
-      }
-    }
-  }
-
-  #[test]
-  fn basic_symbol_table() {
-    values_in_table! { "let a = 10; fn b() { 20 }", &fqsn!("b"; tr) }
-  }
-
-  #[test]
-  fn no_duplicates() {
-    let source = r#"
-    fn a() { 1 }
-    fn b() { 2 }
-    fn a() { 3 }
-    "#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
-    assert!(output.contains("Duplicate"))
-  }
-
-  #[test]
-  fn no_duplicates_2() {
-    let source = r#"
-    let a = 20;
-    let q = 39;
-    let a = 30;
-    "#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
-    assert!(output.contains("Duplicate"))
-  }
-
-  #[test]
-  fn no_duplicates_3() {
-    let source = r#"
-    fn a() {
-      let a = 20
-      let b = 40
-      a + b
-    }
-
-    fn q() {
-      let x = 30
-      let x = 33
-    }
-    "#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
-    assert!(output.contains("Duplicate"))
-  }
-
-  #[test]
-  fn dont_falsely_detect_duplicates() {
-    let source = r#"
-    let a = 20;
-    fn some_func() {
-      let a = 40;
-      77
-    }
-    let q = 39;
-    "#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    symbol_table.add_top_level_symbols(&ast).unwrap();
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!["a"; tr]).is_some());
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!["some_func"; fn, "a";tr]).is_some());
-  }
-
-  #[test]
-  fn enclosing_scopes() {
-    let source = r#"
-fn outer_func(x) {
-  fn inner_func(arg) {
-    arg
-  }
-  x + inner_func(x)
-}"#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    symbol_table.add_top_level_symbols(&ast).unwrap();
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; tr)).is_some());
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
-  }
-
-  #[test]
-  fn enclosing_scopes_2() {
-    let source = r#"
-fn outer_func(x) {
-  fn inner_func(arg) {
-    arg
-  }
-
-  fn second_inner_func() {
-    fn another_inner_func() {
-    }
-  }
-
-  inner_func(x)
-}"#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    symbol_table.add_top_level_symbols(&ast).unwrap();
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; tr)).is_some());
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "second_inner_func"; tr)).is_some());
-    assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "second_inner_func"; fn, "another_inner_func"; tr)).is_some());
-  }
-
-  #[test]
-  fn enclosing_scopes_3() {
-    let source = r#"
-fn outer_func(x) {
-  fn inner_func(arg) {
-    arg
-  }
-
-  fn second_inner_func() {
-    fn another_inner_func() {
-    }
-    fn another_inner_func() {
-    }
-  }
-
-  inner_func(x)
-}"#;
-    let mut symbol_table = SymbolTable::new();
-    let ast = quick_ast(source);
-    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
-    assert!(output.contains("Duplicate"))
-  }
-}
-

schala-lang/language/src/symbol_table/symbol_trie.rs

@@ -0,0 +1,51 @@
+use radix_trie::{Trie, TrieCommon, TrieKey};
+use super::FullyQualifiedSymbolName;
+use std::hash::{Hasher, Hash};
+use std::collections::hash_map::DefaultHasher;
+
+#[derive(Debug)]
+pub struct SymbolTrie(Trie<FullyQualifiedSymbolName, ()>);
+
+impl TrieKey for FullyQualifiedSymbolName {
+  fn encode_bytes(&self) -> Vec<u8> {
+    let mut hasher = DefaultHasher::new();
+    let mut output = vec![];
+    let FullyQualifiedSymbolName(scopes) = self;
+    for segment in scopes.iter() {
+      segment.name.as_bytes().hash(&mut hasher);
+      output.extend_from_slice(&hasher.finish().to_be_bytes());
+    }
+    output
+  }
+}
+
+impl SymbolTrie {
+  pub fn new() -> SymbolTrie {
+    SymbolTrie(Trie::new())
+  }
+
+  pub fn insert(&mut self, fqsn: &FullyQualifiedSymbolName) {
+    self.0.insert(fqsn.clone(), ());
+  }
+
+  pub fn get_children(&self, fqsn: &FullyQualifiedSymbolName) -> Vec<FullyQualifiedSymbolName> {
+    let subtrie = match self.0.subtrie(fqsn) {
+      Some(s) => s,
+      None => return vec![]
+    };
+    let output: Vec<FullyQualifiedSymbolName> = subtrie.keys().filter(|cur_key| **cur_key != *fqsn).map(|fqsn| fqsn.clone()).collect();
+    output
+  }
+}
+
+#[test]
+fn test_trie_insertion() {
+  let mut trie = SymbolTrie::new();
+
+  trie.insert(&fqsn!("unrelated"; ty, "thing"; tr));
+  trie.insert(&fqsn!("outer"; ty, "inner"; tr));
+  trie.insert(&fqsn!("outer"; ty, "inner"; ty, "still_inner"; tr));
+
+  let children = trie.get_children(&fqsn!("outer"; ty, "inner"; tr));
+  assert_eq!(children.len(), 1);
+}

schala-lang/language/src/symbol_table/test.rs

@@ -0,0 +1,193 @@
+#![cfg(test)]
+use std::cell::RefCell;
+use std::rc::Rc;
+
+use super::*;
+use crate::util::quick_ast;
+
+fn add_symbols_from_source(src: &str) -> (SymbolTable, Result<(), String>) {
+  let (ast, source_map) = quick_ast(src);
+  let source_map = Rc::new(RefCell::new(source_map));
+  let mut symbol_table = SymbolTable::new(source_map);
+  let result = symbol_table.add_top_level_symbols(&ast);
+  (symbol_table, result)
+}
+
+macro_rules! values_in_table {
+  ($source:expr, $single_value:expr) => {
+    values_in_table!($source => $single_value);
+  };
+  ($source:expr => $( $value:expr ),* ) => {
+    {
+    let (symbol_table, _) = add_symbols_from_source($source);
+    $(
+      match symbol_table.lookup_by_fqsn($value) {
+        Some(_spec) => (),
+        None => panic!(),
+      };
+    )*
+    }
+  };
+}
+
+#[test]
+fn basic_symbol_table() {
+  values_in_table! { "let a = 10; fn b() { 20 }", &fqsn!("b"; tr) };
+  values_in_table! { "type Option<T> = Some(T) | None" =>
+    &fqsn!("Option"; tr),
+    &fqsn!("Option"; ty, "Some"; tr),
+    &fqsn!("Option"; ty, "None"; tr) };
+}
+
+#[test]
+fn no_function_definition_duplicates() {
+  let source = r#"
+  fn a() { 1 }
+  fn b() { 2 }
+  fn a() { 3 }
+  "#;
+  let (_, output) = add_symbols_from_source(source);
+  assert!(output.unwrap_err().contains("Duplicate function definition: a"))
+}
+
+#[test]
+fn no_variable_definition_duplicates() {
+  let source = r#"
+  let x = 9
+  let a = 20
+  let q = 39
+  let a = 30
+  "#;
+  let (_, output) = add_symbols_from_source(source);
+  let output = output.unwrap_err();
+  assert!(output.contains("Duplicate variable definition: a"));
+  assert!(output.contains("already defined at 2"));
+}
+
+#[test]
+fn no_variable_definition_duplicates_in_function() {
+  let source = r#"
+  fn a() {
+    let a = 20
+    let b = 40
+    a + b
+  }
+
+  fn q() {
+    let a = 29
+    let x = 30
+    let x = 33
+  }
+  "#;
+  let (_, output) = add_symbols_from_source(source);
+  assert!(output.unwrap_err().contains("Duplicate variable definition: x"))
+}
+
+#[test]
+fn dont_falsely_detect_duplicates() {
+  let source = r#"
+  let a = 20;
+  fn some_func() {
+    let a = 40;
+    77
+  }
+  let q = 39;
+  "#;
+  let (symbol_table, _) = add_symbols_from_source(source);
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!["a"; tr]).is_some());
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!["some_func"; fn, "a";tr]).is_some());
+}
+
+#[test]
+fn enclosing_scopes() {
+  let source = r#"
+fn outer_func(x) {
+fn inner_func(arg) {
+  arg
+}
+x + inner_func(x)
+}"#;
+  let (symbol_table, _) = add_symbols_from_source(source);
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; tr)).is_some());
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
+}
+
+#[test]
+fn enclosing_scopes_2() {
+  let source = r#"
+fn outer_func(x) {
+fn inner_func(arg) {
+  arg
+}
+
+fn second_inner_func() {
+  fn another_inner_func() {
+  }
+}
+
+inner_func(x)
+}"#;
+  let (symbol_table, _) = add_symbols_from_source(source);
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; tr)).is_some());
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "second_inner_func"; tr)).is_some());
+  assert!(symbol_table.lookup_by_fqsn(&fqsn!("outer_func"; fn, "second_inner_func"; fn, "another_inner_func"; tr)).is_some());
+}
+
+#[test]
+fn enclosing_scopes_3() {
+  let source = r#"
+fn outer_func(x) {
+fn inner_func(arg) {
+  arg
+}
+
+fn second_inner_func() {
+  fn another_inner_func() {
+  }
+  fn another_inner_func() {
+  }
+}
+
+inner_func(x)
+}"#;
+  let (_, output) = add_symbols_from_source(source);
+  assert!(output.unwrap_err().contains("Duplicate"))
+}
+
+#[test]
+fn modules() {
+  let source = r#"
+module stuff {
+  fn item() {
+  }
+}
+
+fn item()
+"#;
+  values_in_table! { source  =>
+    &fqsn!("item"; tr),
+    &fqsn!("stuff"; tr, "item"; tr)
+  };
+}
+
+#[test]
+fn duplicate_modules() {
+  let source = r#"
+    module q {
+      fn foo() { 4 }
+    }
+
+    module a {
+      fn foo() { 334 }
+    }
+
+    module a {
+      fn foo() { 256.1 }
+    }
+    "#;
+  let (_, output) = add_symbols_from_source(source);
+  let output = output.unwrap_err();
+  assert!(output.contains("Duplicate module"));
+  assert!(output.contains("already defined at 5"));
+}

schala-lang/language/src/tokenizing.rs

@@ -4,6 +4,8 @@ use std::rc::Rc;
 use std::iter::{Iterator, Peekable};
 use std::fmt;
 
+use crate::source_map::Location;
+
 #[derive(Debug, PartialEq, Clone)]
 pub enum TokenKind {
   Newline, Semicolon,
@@ -19,7 +21,10 @@ pub enum TokenKind {
 
   Operator(Rc<String>),
   DigitGroup(Rc<String>), HexLiteral(Rc<String>), BinNumberSigil,
-  StrLiteral(Rc<String>),
+  StrLiteral {
+    s: Rc<String>,
+    prefix: Option<Rc<String>>
+  },
   Identifier(Rc<String>),
   Keyword(Kw),
 
@@ -35,7 +40,7 @@ impl fmt::Display for TokenKind {
       &Operator(ref s) => write!(f, "Operator({})", **s),
       &DigitGroup(ref s) => write!(f, "DigitGroup({})", s),
       &HexLiteral(ref s) => write!(f, "HexLiteral({})", s),
-      &StrLiteral(ref s) => write!(f, "StrLiteral({})", s),
+      &StrLiteral {ref s, .. } => write!(f, "StrLiteral({})", s),
       &Identifier(ref s) => write!(f, "Identifier({})", s),
       &Error(ref s) => write!(f, "Error({})", s),
       other => write!(f, "{:?}", other),
@@ -55,7 +60,7 @@ pub enum Kw {
   Alias, Type, SelfType, SelfIdent,
   Interface, Impl,
   True, False,
-  Module
+  Module, Import
 }
 
 lazy_static! {
@@ -82,14 +87,14 @@ lazy_static! {
       "true" => Kw::True,
       "false" => Kw::False,
       "module" => Kw::Module,
+      "import" => Kw::Import,
     };
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Token {
   pub kind: TokenKind,
-  pub line_num: usize,
-  pub char_num: usize
+  pub location: Location,
 }
 
 impl Token {
@@ -100,7 +105,7 @@ impl Token {
     }
   }
   pub fn to_string_with_metadata(&self) -> String {
-    format!("{}(L:{},c:{})", self.kind, self.line_num, self.char_num)
+    format!("{}({})", self.kind, self.location)
   }
 
   pub fn get_kind(&self) -> TokenKind {
@@ -161,14 +166,15 @@ pub fn tokenize(input: &str) -> Vec<Token> {
       '(' => LParen, ')' => RParen,
       '{' => LCurlyBrace, '}' => RCurlyBrace,
       '[' => LSquareBracket, ']' => RSquareBracket,
-      '"' => handle_quote(&mut input),
+      '"' => handle_quote(&mut input, None),
       '\\' => Backslash,
       c if c.is_digit(10) => handle_digit(c, &mut input),
       c if c.is_alphabetic() || c == '_' => handle_alphabetic(c, &mut input),
       c if is_operator(&c) => handle_operator(c, &mut input),
       unknown => Error(format!("Unexpected character: {}", unknown)),
     };
-    tokens.push(Token { kind: cur_tok_kind, line_num, char_num });
+    let location = Location { line_num, char_num };
+    tokens.push(Token { kind: cur_tok_kind, location });
   }
   tokens
 }
@@ -188,7 +194,7 @@ fn handle_digit(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) ->
   }
 }
 
-fn handle_quote(input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
+fn handle_quote(input: &mut Peekable<impl Iterator<Item=CharData>>, quote_prefix: Option<&str>) -> TokenKind {
   let mut buf = String::new();
   loop {
     match input.next().map(|(_, _, c)| { c }) {
@@ -210,7 +216,7 @@ fn handle_quote(input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind
       None => return TokenKind::Error(format!("Unclosed string")),
     }
   }
-  TokenKind::StrLiteral(Rc::new(buf))
+  TokenKind::StrLiteral { s: Rc::new(buf), prefix: quote_prefix.map(|s| Rc::new(s.to_string())) }
 }
 
 fn handle_alphabetic(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
@@ -222,6 +228,10 @@ fn handle_alphabetic(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>
 
   loop {
     match input.peek().map(|&(_, _, c)| { c }) {
+      Some(c) if c == '"' => {
+        input.next();
+        return handle_quote(input, Some(&buf));
+      },
       Some(c) if c.is_alphanumeric() || c == '_' => {
         input.next();
         buf.push(c);
@@ -322,4 +332,13 @@ mod schala_tokenizer_tests {
     let token_kinds: Vec<TokenKind> = tokenize("1 `plus` 2").into_iter().map(move |t| t.kind).collect();
     assert_eq!(token_kinds, vec![digit!("1"), op!("plus"), digit!("2")]);
   }
+
+  #[test]
+  fn string_literals() {
+    let token_kinds: Vec<TokenKind> = tokenize(r#""some string""#).into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![StrLiteral { s: Rc::new("some string".to_string()), prefix: None }]);
+
+    let token_kinds: Vec<TokenKind> = tokenize(r#"b"some bytestring""#).into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![StrLiteral { s: Rc::new("some bytestring".to_string()), prefix: Some(Rc::new("b".to_string())) }]);
+  }
 }

schala-lang/language/src/typechecking.rs

@@ -5,6 +5,7 @@ use ena::unify::{UnifyKey, InPlaceUnificationTable, UnificationTable, EqUnifyVal
 
 use crate::ast::*;
 use crate::util::ScopeStack;
+use crate::util::deref_optional_box;
 
 
 #[derive(Debug, Clone, PartialEq)]
@@ -13,6 +14,7 @@ pub struct TypeData {
 }
 
 impl TypeData {
+  #[allow(dead_code)]
   pub fn new() -> TypeData {
     TypeData { ty: None }
   }
@@ -274,6 +276,8 @@ impl<'a> TypeContext<'a> {
     match &statement.kind {
       StatementKind::Expression(e) => self.expr(e),
       StatementKind::Declaration(decl) => self.decl(&decl),
+      StatementKind::Import(_) => Ok(ty!(Unit)),
+      StatementKind::Module(_) => Ok(ty!(Unit)),
     }
   }
 
@@ -317,7 +321,7 @@ impl<'a> TypeContext<'a> {
       StringLiteral(_) => ty!(StringT),
       PrefixExp(op, expr) => self.prefix(op, expr)?,
       BinExp(op, lhs, rhs) => self.binexp(op, lhs, rhs)?,
-      IfExpression { discriminator, body } => self.if_expr(discriminator, body)?,
+      IfExpression { discriminator, body } => self.if_expr(deref_optional_box(discriminator), &**body)?,
       Value(val) => self.handle_value(val)?,
       Call { box ref f, arguments } => self.call(f, arguments)?,
       Lambda { params, type_anno, body } => self.lambda(params, type_anno, body)?,
@@ -347,10 +351,10 @@ impl<'a> TypeContext<'a> {
     self.handle_apply(tf, vec![t_lhs, t_rhs])
   }
 
-  fn if_expr(&mut self, discriminator: &Discriminator, body: &IfExpressionBody) -> InferResult<Type> {
-    use self::Discriminator::*; use self::IfExpressionBody::*;
+  fn if_expr(&mut self, discriminator: Option<&Expression>, body: &IfExpressionBody) -> InferResult<Type> {
+    use self::IfExpressionBody::*;
     match (discriminator, body) {
-      (Simple(expr), SimpleConditional(then_clause, else_clause)) => self.handle_simple_if(expr, then_clause, else_clause),
+      (Some(expr), SimpleConditional{ then_case, else_case }) => self.handle_simple_if(expr, then_case, else_case),
       _ => TypeError::new(format!("Complex conditionals not supported"))
     }
   }
@@ -458,7 +462,7 @@ mod typechecking_tests {
   macro_rules! assert_type_in_fresh_context {
     ($string:expr, $type:expr) => {
       let mut tc = TypeContext::new();
-      let ref ast = crate::util::quick_ast($string);
+      let (ref ast, _) = crate::util::quick_ast($string);
       let ty = tc.typecheck(ast).unwrap();
       assert_eq!(ty, $type)
     }

schala-lang/language/src/util.rs

@@ -1,6 +1,11 @@
 use std::collections::HashMap;
 use std::hash::Hash;
 use std::cmp::Eq;
+use std::ops::Deref;
+
+pub fn deref_optional_box<T>(x: &Option<Box<T>>) -> Option<&T> {
+  x.as_ref().map(|b: &Box<T>| Deref::deref(b))
+}
 
 #[derive(Default, Debug)]
 pub struct ScopeStack<'a, T: 'a, V: 'a>  where T: Hash + Eq {
@@ -43,10 +48,18 @@ impl<'a, T, V> ScopeStack<'a, T, V> where T: Hash + Eq {
 
 /// this is intended for use in tests, and does no error-handling whatsoever
 #[allow(dead_code)]
-pub fn quick_ast(input: &str) -> crate::ast::AST {
+pub fn quick_ast(input: &str) -> (crate::ast::AST, crate::source_map::SourceMap) {
+  use std::cell::RefCell;
+  use std::rc::Rc;
+
+  let source_map = crate::source_map::SourceMap::new();
+  let source_map_handle = Rc::new(RefCell::new(source_map));
   let tokens = crate::tokenizing::tokenize(input);
-  let mut parser = crate::parsing::Parser::new(tokens);
-  parser.parse().unwrap()
+  let mut parser = crate::parsing::Parser::new(source_map_handle.clone());
+  parser.add_new_tokens(tokens);
+  let output = parser.parse();
+  std::mem::drop(parser);
+  (output.unwrap(), Rc::try_unwrap(source_map_handle).map_err(|_| ()).unwrap().into_inner())
 }
 
 #[allow(unused_macros)]

schala-repl/src/repl/command_tree.rs

@@ -49,8 +49,8 @@ impl CommandTree {
   }
   pub fn get_help(&self) -> &str {
     match self {
-      CommandTree::Terminal { help_msg, ..} => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
-      CommandTree::NonTerminal { help_msg, .. } => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
+      CommandTree::Terminal { help_msg, ..} => help_msg.as_ref().map(|s| s.as_str()).unwrap_or("<no help text provided>"),
+      CommandTree::NonTerminal { help_msg, .. } => help_msg.as_ref().map(|s| s.as_str()).unwrap_or("<no help text provided>"),
       CommandTree::Top(_) => ""
     }
   }

schala-repl/src/repl/help.rs

@@ -13,7 +13,12 @@ pub fn help(repl: &mut Repl, arguments: &[&str]) -> InterpreterDirectiveOutput {
         None => format!("Directive `{}` not found", commands.last().unwrap()),
         Some(dir) => {
           let mut buf = String::new();
-          writeln!(buf, "`{}` - {}", dir.get_cmd(), dir.get_help()).unwrap();
+          let cmd = dir.get_cmd();
+          let children = dir.get_children();
+          writeln!(buf, "`{}` - {}", cmd, dir.get_help()).unwrap();
+          for sub in children.iter() {
+            writeln!(buf, "\t`{} {}` - {}", cmd, sub.get_cmd(), sub.get_help()).unwrap();
+          }
           buf
         }
       })

schala-repl/src/repl/mod.rs

@@ -27,6 +27,12 @@ pub struct Repl {
   options: ReplOptions,
 }
 
+#[derive(Clone)]
+enum PromptStyle {
+  Normal,
+  Multiline
+}
+
 impl Repl {
   pub fn new(initial_states: Vec<Box<dyn ProgrammingLanguageInterface>>) -> Repl {
     use linefeed::Interface;
@@ -62,37 +68,73 @@ impl Repl {
 
   fn handle_repl_loop(&mut self) {
     use linefeed::ReadResult::*;
+    let sigil = self.interpreter_directive_sigil;
 
-    loop {
-      self.update_line_reader();
-      match self.line_reader.read_line() {
-        Err(e) => {
-          println!("readline IO Error: {}", e);
-          break;
-        },
-        Ok(Eof) | Ok(Signal(_)) => break,
-        Ok(Input(ref input)) => {
-          self.line_reader.add_history_unique(input.to_string());
-          match input.chars().nth(0) {
-            Some(ch) if ch == self.interpreter_directive_sigil => match self.handle_interpreter_directive(input) {
-              Some(directive_output) => println!("<> {}", directive_output),
-              None => (),
+    'main: loop {
+      macro_rules! match_or_break {
+        ($line:expr) => {
+          match $line {
+            Err(e) => {
+              println!("readline IO Error: {}", e);
+              break 'main;
             },
-            _ => {
-              for repl_response in self.handle_input(input) {
-                println!("{}", repl_response);
-              }
-            }
+            Ok(Eof) | Ok(Signal(_)) => break 'main,
+            Ok(Input(ref input)) => input,
           }
         }
       }
+      self.update_line_reader();
+      let line = self.line_reader.read_line();
+      let input: &str = match_or_break!(line);
+
+      self.line_reader.add_history_unique(input.to_string());
+      let mut chars = input.chars().peekable();
+      let repl_responses = match chars.nth(0) {
+        Some(ch) if ch == sigil => {
+          if chars.peek() == Some(&'{') {
+            let mut buf = String::new();
+            buf.push_str(input.get(2..).unwrap());
+            'multiline: loop {
+              self.set_prompt(PromptStyle::Multiline);
+              let new_line = self.line_reader.read_line();
+              let new_input = match_or_break!(new_line);
+              if new_input.starts_with(":}") {
+                break 'multiline;
+              } else {
+                buf.push_str(new_input);
+                buf.push_str("\n");
+              }
+            }
+            self.handle_input(&buf)
+          } else {
+            match self.handle_interpreter_directive(input) {
+              Some(directive_output) => println!("<> {}", directive_output),
+              None => (),
+            }
+            continue
+          }
+        },
+        _ => self.handle_input(input)
+      };
+
+      for repl_response in repl_responses.iter() {
+        println!("{}", repl_response);
+      }
     }
   }
 
   fn update_line_reader(&mut self) {
     let tab_complete_handler = TabCompleteHandler::new(self.interpreter_directive_sigil, self.get_directives());
     self.line_reader.set_completer(Arc::new(tab_complete_handler)); //TODO fix this here
-    let prompt_str = format!(">> ");
+    self.set_prompt(PromptStyle::Normal);
+  }
+
+  fn set_prompt(&mut self, prompt_style: PromptStyle) {
+    let prompt_str = match prompt_style {
+      PromptStyle::Normal => ">> ".to_string(),
+      PromptStyle::Multiline => ">| ".to_string(),
+    };
+
     self.line_reader.set_prompt(&prompt_str).unwrap();
   }