From 170cf349d7ed62723f64c08219b10686f13655d3 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Sat, 9 Feb 2019 00:25:12 -0800
Subject: [PATCH] Starting typechecking work again

---
 schala-lang/language/src/typechecking.rs | 141 +----------------------
 1 file changed, 4 insertions(+), 137 deletions(-)

diff --git a/schala-lang/language/src/typechecking.rs b/schala-lang/language/src/typechecking.rs
index df47e87..4c10b73 100644
--- a/schala-lang/language/src/typechecking.rs
+++ b/schala-lang/language/src/typechecking.rs
@@ -6,7 +6,7 @@ use crate::util::ScopeStack;
 pub type TypeName = Rc<String>;
 
 pub struct TypeContext<'a> {
-  variable_map: ScopeStack<'a, Rc<String>, Type<TVar>>,
+  variable_map: ScopeStack<'a, Rc<String>, ()>,
   evar_count: u32
 }
 
@@ -22,6 +22,7 @@ impl TypeError {
   }
 }
 
+/*
 /// `Type` is parameterized by whether the type variables can be just universal, or universal or
 /// existential.
 #[derive(Debug, Clone)]
@@ -104,6 +105,7 @@ impl TConst {
     TConst::User(Rc::new(name.to_string()))
   }
 }
+*/
 
 impl<'a> TypeContext<'a> {
   pub fn new() -> TypeContext<'a> {
@@ -114,141 +116,6 @@ impl<'a> TypeContext<'a> {
   }
 
   pub fn typecheck(&mut self, ast: &AST) -> Result<String, String> {
-    match self.infer_ast(ast) {
-      Ok(t) => Ok(format!("{:?}", t)),
-      Err(err) => Err(format!("Type error: {:?}", err))
-    }
-  }
-}
-
-impl<'a> TypeContext<'a> {
-  fn infer_ast(&mut self, ast: &AST) -> InferResult<Type<UVar>> {
-    self.infer_block(&ast.0)
-  }
-
-  fn infer_statement(&mut self, stmt: &Statement) -> InferResult<Type<UVar>> {
-    match stmt {
-      Statement::ExpressionStatement(ref expr) => self.infer_expr(expr.node()),
-      Statement::Declaration(ref decl) => self.infer_decl(decl),
-    }
-  }
-
-  fn infer_expr(&mut self, expr: &Expression) -> InferResult<Type<UVar>> {
-    match expr {
-      Expression(expr_type, Some(type_anno)) => {
-        let tx = self.infer_expr_type(expr_type)?;
-        let ty = type_anno.to_monotype();
-        self.unify(&ty.to_tvar(), &tx.to_tvar()).map(|x| x.skolemize())
-      },
-      Expression(expr_type, None) => self.infer_expr_type(expr_type)
-    }
-  }
-
-  fn infer_decl(&mut self, _decl: &Declaration) -> InferResult<Type<UVar>> {
-    Ok(Type::Const(TConst::user("unimplemented")))
-  }
-
-  fn infer_expr_type(&mut self, expr_type: &ExpressionType) -> InferResult<Type<UVar>> {
-    use self::ExpressionType::*;
-    Ok(match expr_type {
-      NatLiteral(_) => Type::Const(TConst::Nat),
-      FloatLiteral(_) => Type::Const(TConst::Float),
-      StringLiteral(_) => Type::Const(TConst::StringT),
-      BoolLiteral(_) => Type::Const(TConst::Bool),
-      Value(name) => {
-        //TODO handle the distinction between 0-arg constructors and variables at some point
-        // need symbol table for that
-        match self.variable_map.lookup(name) {
-          Some(ty) => ty.clone().skolemize(),
-          None => return TypeError::new(&format!("Variable {} not found", name))
-        }
-      },
-      IfExpression { discriminator, body } => self.infer_if_expr(discriminator, body)?,
-      Call { f, arguments } => {
-        let tf = self.infer_expr(f)?; //has to be an Arrow Type
-        let targ = self.infer_expr(&arguments[0].node())?; // TODO make this work with functions with more than one arg
-        match tf {
-          Type::Arrow(t1, t2) => {
-            self.unify(&t1.to_tvar(), &targ.to_tvar())?;
-            *t2.clone()
-          },
-          _ => return TypeError::new("not a function")
-        }
-      },
-
-      Lambda { params, .. } => {
-
-        let _arg_type = match &params[0] {
-          (_, Some(type_anno)) => type_anno.to_monotype().to_tvar(),
-          (_, None) => self.allocate_existential(),
-        };
-        //let _result_type = unimplemented!();
-        return TypeError::new("Unimplemented");
-
-        //Type::Arrow(Box::new(arg_type), Box::new(result_type))
-      }
-      _ => Type::Const(TConst::user("unimplemented"))
-    })
-  }
-
-  fn infer_if_expr(&mut self, discriminator: &Discriminator, body: &IfExpressionBody) -> InferResult<Type<UVar>> {
-    let _test = match discriminator {
-      Discriminator::Simple(expr) => expr,
-      _ => return TypeError::new("Dame desu")
-    };
-
-    let (_then_clause, _maybe_else_clause) = match body {
-      IfExpressionBody::SimpleConditional(a, b) => (a, b),
-      _ => return TypeError::new("Dont work")
-    };
-
-    TypeError::new("Not implemented")
-  }
-
-  fn infer_block(&mut self, block: &Block) -> InferResult<Type<UVar>> {
-    let mut output = Type::Const(TConst::Unit);
-    for statement in block.iter() {
-      output = self.infer_statement(statement.node())?;
-    }
-    Ok(output)
-  }
-
-  fn unify(&mut self, _t1: &Type<TVar>, _t2: &Type<TVar>) -> InferResult<Type<TVar>> {
-    TypeError::new("not implemented")
-  }
-
-  fn allocate_existential(&mut self) -> Type<TVar> {
-    let n = self.evar_count;
-    self.evar_count += 1;
-    Type::Var(TVar::Exist(ExistentialVar(n)))
-  }
-}
-
-#[cfg(test)]
-mod tests {
-  use super::*;
-
-  fn parse(input: &str) -> AST {
-    let tokens: Vec<crate::tokenizing::Token> = crate::tokenizing::tokenize(input);
-    let mut parser = crate::parsing::Parser::new(tokens);
-    parser.parse().unwrap()
-  }
-
-  macro_rules! type_test {
-    ($input:expr, $correct:expr) => {
-      {
-      let mut tc = TypeContext::new();
-      let ast = parse($input);
-      tc.add_symbols(&ast);
-      assert_eq!($correct, tc.type_check(&ast).unwrap())
-      }
-    }
-  }
-
-
-
-  #[test]
-  fn basic_inference() {
-
+    Ok(format!("UNIT"))
   }
 }