From 647a095a05e566a23023cd4887d80ac82900be2c Mon Sep 17 00:00:00 2001
From: Moritz Gmeiner <moritz@gmeiner.net>
Date: Sat, 28 Jan 2023 21:11:01 +0100
Subject: [PATCH] Interpreter finish

---
 frontend/src/parser/stmt.rs    |  2 +-
 interpreter/src/environment.rs | 17 +++++++++++------
 interpreter/src/error.rs       |  2 +-
 interpreter/src/interpret.rs   | 22 +++++++++++++---------
 interpreter/src/run.rs         |  7 +++----
 5 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/frontend/src/parser/stmt.rs b/frontend/src/parser/stmt.rs
index dc7299b..db0506a 100644
--- a/frontend/src/parser/stmt.rs
+++ b/frontend/src/parser/stmt.rs
@@ -82,7 +82,7 @@ impl Stmt {
 impl Display for Stmt {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Stmt::Print { expr } => write!(f, "print {expr};"),
+            Stmt::Print { expr } => write!(f, "(print {expr});"),
             Stmt::IfStmt {
                 condition,
                 then_branch,
diff --git a/interpreter/src/environment.rs b/interpreter/src/environment.rs
index f118e5f..11809a6 100644
--- a/interpreter/src/environment.rs
+++ b/interpreter/src/environment.rs
@@ -36,22 +36,27 @@ impl<'a> Environment<'a> {
         self.local_scopes.push(Scope::new());
     }
 
-    pub fn push_scope(&mut self, scope: Scope) {
-        self.local_scopes.push(scope);
-    }
-
     pub fn exit_scope(&mut self) {
         // self.current_frame_mut().exit_scope();
         self.local_scopes.pop().expect("Tried to pop global scope");
     }
 
+    pub fn insert_closure(&mut self, closure: Scope) {
+        let scope = self.local_scopes.last_mut().unwrap();
+
+        for (name, value) in closure {
+            scope.insert(name, value);
+        }
+    }
+
     pub fn get_global(&self, name: &str) -> Result<Value, RuntimeError> {
         self.runtime.get_global(name)
     }
 
     pub fn get_local(&self, name: &str, level: usize) -> Result<Value, RuntimeError> {
-        if let Some(scope) = self.local_scopes.iter().rev().nth(level) {
-            if let Some(heap_value) = scope.get(name) {
+        let len = self.local_scopes.len();
+        if level < len {
+            if let Some(heap_value) = self.local_scopes[len - level - 1].get(name) {
                 return Ok(heap_value.get_clone());
             }
         }
diff --git a/interpreter/src/error.rs b/interpreter/src/error.rs
index 6efdf5b..1467393 100644
--- a/interpreter/src/error.rs
+++ b/interpreter/src/error.rs
@@ -16,7 +16,7 @@ pub enum RuntimeError {
     BinaryOpInvalidArguments { left: Value, op: BinaryOp, right: Value },
     #[error("Division by zero")]
     DivisionByZero,
-    #[error("Name {name} is not defined")]
+    #[error("Local {name} is not defined")]
     NameNotDefined { name: String },
     #[error("Global {name} is not defined")]
     GlobalNotDefined { name: String },
diff --git a/interpreter/src/interpret.rs b/interpreter/src/interpret.rs
index fcf995e..61065f2 100644
--- a/interpreter/src/interpret.rs
+++ b/interpreter/src/interpret.rs
@@ -133,7 +133,7 @@ impl Eval for Expr {
                     .collect::<EvalResult<Vec<Value>>>()?;
 
                 match callee {
-                    Value::Function(fun) => fun.call(args, env),
+                    Value::Function(fun) => LoxFunction::call(fun, args, env),
                     Value::ExternFunction(ext_fun) => ext_fun.call(args, env),
                     Value::Class(class) => LoxClass::call(class, args, env),
                     _ => Err(RuntimeError::NotCallable { callee }),
@@ -286,22 +286,26 @@ impl Eval for Stmt {
 /*====================================================================================================================*/
 
 impl LoxFunction {
-    pub fn call(&self, args: Vec<Value>, env: &mut Environment) -> EvalResult<Value> {
-        if args.len() != self.arity() {
+    pub fn call(fun: Rc<LoxFunction>, args: Vec<Value>, env: &mut Environment) -> EvalResult<Value> {
+        if args.len() != fun.arity() {
             return Err(RuntimeError::WrongArity {
-                name: self.name().to_owned(),
-                arity: self.arity(),
+                name: fun.name().to_owned(),
+                arity: fun.arity(),
                 given: args.len(),
             });
         }
 
-        env.push_scope(self.closure().clone());
+        env.enter_scope();
 
-        for (name, value) in std::iter::zip(self.param_names(), args) {
+        env.define(fun.name(), Value::Function(fun.clone()));
+
+        env.insert_closure(fun.closure().clone());
+
+        for (name, value) in std::iter::zip(fun.param_names(), args) {
             env.define(name, value);
         }
 
-        let ret_val = match self.body().eval(env) {
+        let ret_val = match fun.body().eval(env) {
             Ok(_) => Ok(Value::Nil),
             Err(RuntimeError::Return { value }) => Ok(value),
             Err(err) => Err(err),
@@ -343,7 +347,7 @@ impl LoxClass {
         // object.init(args, env)?;
 
         if let Some(Value::Function(method)) = object.get("init") {
-            method.call(args, env)?;
+            LoxFunction::call(method, args, env)?;
         }
 
         Ok(Value::Object(object))
diff --git a/interpreter/src/run.rs b/interpreter/src/run.rs
index 2de073b..5828ed3 100644
--- a/interpreter/src/run.rs
+++ b/interpreter/src/run.rs
@@ -103,12 +103,11 @@ fn run(code_string: &str, runtime: &mut Runtime) -> Result<(), LoxError> {
         println!("{statement}");
     } */
 
-    /* for statement in statements.iter() {
-        println!("{statement}");
-    } */
-
     for mut statement in statements {
         resolve(&mut statement, runtime)?;
+
+        // println!("{statement}");
+
         execute(statement, runtime)?;
     }