From f4682d80de7bf7edc1a8be0aef0cdd0040149078 Mon Sep 17 00:00:00 2001
From: David Li <li.davidm96@gmail.com>
Date: Sun, 26 Nov 2017 20:03:22 -0500
Subject: Translate variable references

---
 src/semantic/analysis.rs  | 28 +++++++++++++++-------------
 src/semantic/ir.rs        |  6 +++---
 src/semantic/translate.rs |  2 +-
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/semantic/analysis.rs b/src/semantic/analysis.rs
index 152ede9..829e7c2 100644
--- a/src/semantic/analysis.rs
+++ b/src/semantic/analysis.rs
@@ -7,7 +7,7 @@ use ::ast::{self, WithLocation};
 use super::environment;
 use super::frame;
 use super::ir;
-use super::translate::{self, Level, Translate};
+use super::translate::{self, Expression, Level, Translate};
 use super::types::{self, Ty};
 
 #[derive(Debug)]
@@ -24,6 +24,7 @@ pub enum TypeError {
     UnboundName,
 }
 
+type VarEnvironment<'a> = environment::Environment<'a, String, (Expression, Ty)>;
 type TypeEnvironment<'a> = environment::Environment<'a, String, Ty>;
 pub type Result<T> = ::std::result::Result<T, WithLocation<TypeError>>;
 
@@ -32,7 +33,7 @@ pub fn translate<'a, F: frame::Frame>(
     level: &mut Level<'a, F>,
     program: &ast::Program)
     -> Result<(translate::Expression, Ty)> {
-    let mut venv = TypeEnvironment::new(None);
+    let mut venv = VarEnvironment::new(None);
     let mut tenv = TypeEnvironment::new(None);
     tenv.add_binding("int".into(), Ty::Int);
     tenv.add_binding("string".into(), Ty::String);
@@ -46,7 +47,7 @@ macro_rules! err {
 }
 
 fn trans_ty<'a>(
-    venv: &mut TypeEnvironment<'a>,
+    venv: &mut VarEnvironment<'a>,
     tenv: &mut TypeEnvironment<'a>,
     ty: &WithLocation<ast::Ty>) -> Result<Ty> {
     match ty.value {
@@ -73,7 +74,7 @@ fn trans_ty<'a>(
 fn trans_decl<'a, 'b, F: frame::Frame>(
     tr: &mut Translate<F>,
     level: &mut Level<'b, F>,
-    venv: &mut TypeEnvironment<'a>,
+    venv: &mut VarEnvironment<'a>,
     tenv: &mut TypeEnvironment<'a>,
     decl: &WithLocation<ast::Declaration>) -> Result<(translate::Expression, Ty)> {
     match decl.declaration {
@@ -82,13 +83,14 @@ fn trans_decl<'a, 'b, F: frame::Frame>(
                 Some(ast::WithLocation::new(trans_ty(venv, tenv, &ty)?, ty.start, ty.end))
             } else { None };
 
-            let mut new_venv = TypeEnvironment::new(Some(venv));
+            let mut new_venv = VarEnvironment::new(Some(venv));
             let mut new_tenv = TypeEnvironment::new(Some(tenv));
             let mut arg_types = vec![];
             for param in params.iter() {
                 let arg_ty = trans_ty(&mut new_venv, &mut new_tenv, &param.ty)?;
                 arg_types.push(arg_ty.clone());
-                new_venv.add_binding(param.name.value.clone(), arg_ty);
+                // TODO:
+                // new_venv.add_binding(param.name.value.clone(), arg_ty);
             }
 
             let (body_exp, body_ty) =
@@ -130,7 +132,7 @@ fn trans_decl<'a, 'b, F: frame::Frame>(
 fn trans_exp<'a, 'b, F: frame::Frame>(
     tr: &mut Translate<F>,
     level: &mut Level<'b, F>,
-    venv: &mut TypeEnvironment<'a>,
+    venv: &mut VarEnvironment<'a>,
     tenv: &mut TypeEnvironment<'a>,
     exp: &WithLocation<ast::Expression>)
     -> Result<(translate::Expression, Ty)> {
@@ -138,13 +140,13 @@ fn trans_exp<'a, 'b, F: frame::Frame>(
 
     match &exp.value {
         &Let(ref decls, ref body) => {
-            let mut new_venv = TypeEnvironment::new(Some(venv));
+            let mut new_venv = VarEnvironment::new(Some(venv));
             let mut new_tenv = TypeEnvironment::new(Some(tenv));
             for decl in decls.iter() {
                 let (decl_exp, decl_ty) = trans_decl(tr, level, &mut new_venv, &mut new_tenv, decl)?;
                 match decl.declaration {
                     ast::DeclarationBody::Fun { .. } | ast::DeclarationBody::Var { .. } => {
-                        new_venv.add_binding(decl.name.clone(), decl_ty);
+                        new_venv.add_binding(decl.name.clone(), (decl_exp, decl_ty));
                     }
                     ast::DeclarationBody::Ty { .. } => {
                         new_tenv.add_binding(decl.name.clone(), decl_ty);
@@ -159,7 +161,7 @@ fn trans_exp<'a, 'b, F: frame::Frame>(
                 arg_types.push(trans_exp(tr, level, venv, tenv, arg)?);
             }
 
-            let fun_ty = venv.lookup(name)
+            let &(ref fun_exp, ref fun_ty) = venv.lookup(name)
                 .ok_or(WithLocation::new(TypeError::UnboundName,
                                          exp.start, exp.end))?;
             match fun_ty {
@@ -257,9 +259,9 @@ fn trans_exp<'a, 'b, F: frame::Frame>(
         &String(_) => err!(exp, TypeError::Unimplemented),
         // &String(_) => Ok(Ty::String),
         &Name(ref name) => {
-            if let Some(ty) = venv.lookup(name) {
-                err!(exp, TypeError::Unimplemented)
-                // Ok(ty.clone())
+            if let Some(&(ref exp, ref ty)) = venv.lookup(name) {
+                // TODO: clone might be expensive, Rc?
+                Ok((exp.clone(), ty.clone()))
             }
             else {
                 err!(exp, TypeError::UnboundName)
diff --git a/src/semantic/ir.rs b/src/semantic/ir.rs
index f92cf27..a4ff875 100644
--- a/src/semantic/ir.rs
+++ b/src/semantic/ir.rs
@@ -1,11 +1,11 @@
 use super::temp;
 
-#[derive(Debug)]
+#[derive(Clone,Debug)]
 pub enum BinOp {
     Plus,
 }
 
-#[derive(Debug)]
+#[derive(Clone,Debug)]
 pub enum Expression {
     Const(u64),
     Name(temp::TempLabel),
@@ -16,7 +16,7 @@ pub enum Expression {
     Seq(Vec<Statement>, Box<Expression>),
 }
 
-#[derive(Debug)]
+#[derive(Clone,Debug)]
 pub enum Statement {
     Exp(Expression),
     MoveTemp(temp::TempName, Expression),
diff --git a/src/semantic/translate.rs b/src/semantic/translate.rs
index 5e68f36..f802c3f 100644
--- a/src/semantic/translate.rs
+++ b/src/semantic/translate.rs
@@ -2,7 +2,7 @@ use super::frame;
 use super::ir;
 use super::temp;
 
-#[derive(Debug)]
+#[derive(Clone,Debug)]
 pub enum Expression {
     Exp(ir::Expression),
     Void(ir::Statement),
-- 
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