Start work on qualified names

schala-lang/language/src/ast.rs

@@ -46,6 +46,9 @@ pub enum Statement {
 pub type Block = Vec<Meta<Statement>>;
 pub type ParamName = Rc<String>;
 
+#[derive(Debug, PartialEq, Clone)]
+pub struct QualifiedName(pub Vec<Rc<String>>);
+
 #[derive(Debug, PartialEq, Clone)]
 pub struct FormalParam {
   pub name: ParamName,
@@ -138,9 +141,9 @@ pub enum ExpressionKind {
   BinExp(BinOp, Box<Meta<Expression>>, Box<Meta<Expression>>),
   PrefixExp(PrefixOp, Box<Meta<Expression>>),
   TupleLiteral(Vec<Meta<Expression>>),
-  Value(Rc<String>),
+  Value(QualifiedName),
   NamedStruct {
-    name: Rc<String>,
+    name: QualifiedName,
     fields: Vec<(Rc<String>, Meta<Expression>)>,
   },
   Call {

schala-lang/language/src/parsing.rs

@@ -85,13 +85,14 @@
 //! lambda_param_list := formal_param_list |  formal_param
 //! paren_expr := "(" paren_inner ")"
 //! paren_inner := (expression ",")*
-//! identifier_expr := named_struct | IDENTIFIER
+//! identifier_expr := qualified_identifier | named_struct
+//! qualified_identifier := IDENTIFIER ("::" IDENTIFIER)*
 //! ```
 //!
 //! ## Literals
 //! ```text
 //! literal := "true" | "false" | number_literal | STR_LITERAL
-//! named_struct := IDENTIFIER record_block
+//! named_struct := qualified_identifier record_block
 //! record_block :=  "{" (record_entry, ",")* | "}" //TODO support anonymus structs, update syntax
 //! record_entry := IDENTIFIER ":" expression
 //! anonymous_struct := TODO
@@ -213,6 +214,7 @@ impl TokenHandler {
   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})
   }
+  /// 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})
   }
@@ -757,16 +759,31 @@ impl Parser {
   #[recursive_descent_method]
   fn identifier_expr(&mut self) -> ParseResult<Expression> {
     use self::ExpressionKind::*;
-    let identifier = self.identifier()?;
+    let qualified_identifier = self.qualified_identifier()?;
     Ok(match self.token_handler.peek_kind() {
       LCurlyBrace if !self.restrictions.no_struct_literal => {
         let fields = self.record_block()?;
-        Expression::new(NamedStruct { name: identifier, fields })
+        Expression::new(NamedStruct { name: qualified_identifier, fields })
       },
-      _ => Expression::new(Value(identifier))
+      _ => Expression::new(Value(qualified_identifier))
     })
   }
 
+  #[recursive_descent_method]
+  fn qualified_identifier(&mut self) -> ParseResult<QualifiedName> {
+    let mut vec = vec![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();
+          vec.push(self.identifier()?);
+        },
+        _ => break,
+      }
+    }
+    Ok(QualifiedName(vec))
+  }
+
   #[recursive_descent_method]
   fn record_block(&mut self) -> ParseResult<Vec<(Rc<String>, Meta<Expression>)>> {
     Ok(

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

@@ -4,7 +4,7 @@ use std::str::FromStr;
 
 use super::tokenize;
 use super::ParseResult;
-use crate::ast::{AST, Meta, Expression, Statement, IfExpressionBody, Discriminator, Pattern, PatternLiteral, TypeBody, Enumerator, ForBody, InvocationArgument, FormalParam, PrefixOp, BinOp};
+use crate::ast::{AST, Meta, Expression, Statement, IfExpressionBody, Discriminator, Pattern, PatternLiteral, TypeBody, Enumerator, ForBody, InvocationArgument, FormalParam, PrefixOp, BinOp, QualifiedName};
 use super::Statement::*;
 use super::Declaration::*;
 use super::Signature;
@@ -30,7 +30,7 @@ macro_rules! parse_error {
   ($string:expr) => { assert!(parse($string).is_err()) }
 }
 macro_rules! val {
-  ($var:expr) => { Value(Rc::new($var.to_string())) }
+  ($var:expr) => { Value(QualifiedName(vec![Rc::new($var.to_string())])) };
 }
 macro_rules! ty {
   ($name:expr) => { Singleton(tys!($name)) }
@@ -153,11 +153,11 @@ fn parsing_identifiers() {
 
   parse_test!("None", AST(vec![exst!(val!("None"))]));
   parse_test!("Pandas {  a: x + y }", AST(vec![
-    exst!(NamedStruct { name: rc!(Pandas), fields: vec![(rc!(a), ex!(m binexp!("+", val!("x"), val!("y"))))]})
+    exst!(NamedStruct { name: QualifiedName(vec![rc!(Pandas)]), fields: vec![(rc!(a), ex!(m binexp!("+", val!("x"), val!("y"))))]})
   ]));
   parse_test! { "Pandas { a: n, b: q, }",
   AST(vec![
-      exst!(NamedStruct { name: rc!(Pandas), fields:
+      exst!(NamedStruct { name: QualifiedName(vec![rc!(Pandas)]), fields:
         vec![(rc!(a), ex!(m val!("n"))), (rc!(b), ex!(m val!("q")))]
         }
       )

schala-lang/language/src/reduced_ast.rs

@@ -16,7 +16,7 @@ use std::rc::Rc;
 use std::str::FromStr;
 
 use crate::ast::*;
-use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable};
+use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable, ScopeSegment, ScopeSegmentKind, FullyQualifiedSymbolName};
 use crate::builtin::Builtin;
 
 #[derive(Debug)]
@@ -142,6 +142,21 @@ impl InvocationArgument {
   }
 }
 
+//TODO this is incomplete
+fn lookup_name_in_scope(sym_name: &QualifiedName) -> FullyQualifiedSymbolName {
+  let QualifiedName(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)
+}
+
 impl Expression {
   fn reduce(&self, symbol_table: &SymbolTable) -> Expr {
     use crate::ast::ExpressionKind::*;
@@ -153,14 +168,19 @@ impl Expression {
       BoolLiteral(b) => Expr::Lit(Lit::Bool(*b)),
       BinExp(binop, lhs, rhs) => binop.reduce(symbol_table, lhs, rhs),
       PrefixExp(op, arg) => op.reduce(symbol_table, arg),
-      Value(name) => match symbol_table.lookup_by_name(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) => {
+        let sym_name = lookup_name_in_scope(&qualified_name);
+        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()),
+        }
       },
       Call { f, arguments } =>  reduce_call_expression(f, arguments, symbol_table),
       TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| e.node().reduce(symbol_table)).collect()),
@@ -183,8 +203,12 @@ fn reduce_lambda(params: &Vec<FormalParam>, body: &Block, symbol_table: &SymbolT
   })
 }
 
-fn reduce_named_struct(name: &Rc<String>, fields: &Vec<(Rc<String>, Meta<Expression>)>, symbol_table: &SymbolTable) -> Expr {
-  let (type_name, index, members_from_table) = match symbol_table.lookup_by_name(name) {
+fn reduce_named_struct(name: &QualifiedName, fields: &Vec<(Rc<String>, Meta<Expression>)>, symbol_table: &SymbolTable) -> Expr {
+
+  let sym_name = lookup_name_in_scope(name);
+  let FullyQualifiedSymbolName(ref v) = sym_name;
+  let ref name = v.last().unwrap().name;
+  let (type_name, index, members_from_table) = match symbol_table.lookup_by_fqsn(&sym_name) {
     Some(Symbol { spec: SymbolSpec::RecordConstructor { members, type_name, index },  .. }) => (type_name.clone(), index, members),
     _ => return Expr::ReductionError("Not a record constructor".to_string()),
   };

schala-lang/language/src/symbol_table.rs

@@ -26,8 +26,8 @@ impl fmt::Display for FullyQualifiedSymbolName {
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct ScopeSegment {
-  name: Rc<String>, //TODO maybe this could be a &str, for efficiency?
-  kind: ScopeSegmentKind,
+  pub name: Rc<String>, //TODO maybe this could be a &str, for efficiency?
+  pub kind: ScopeSegmentKind,
 }
 
 impl fmt::Display for ScopeSegment {

schala-lang/language/src/typechecking.rs

@@ -412,10 +412,12 @@ impl<'a> TypeContext<'a> {
     Ok(output)
   }
 
-  fn handle_value(&mut self, val: &Rc<String>) -> InferResult<Type> {
-    match self.variable_map.lookup(val) {
+  fn handle_value(&mut self, val: &QualifiedName) -> InferResult<Type> {
+    let QualifiedName(vec) = val;
+    let var = &vec[0];
+    match self.variable_map.lookup(var) {
       Some(ty) => Ok(ty.clone()),
-      None => TypeError::new(format!("Couldn't find variable: {}", val))
+      None => TypeError::new(format!("Couldn't find variable: {}", &var)),
     }
   }