From f959e1e0cd5b471c64b8dd09d0d279b281128aa2 Mon Sep 17 00:00:00 2001
From: Jason Williams <jase.williams@gmail.com>
Date: Mon, 20 Apr 2020 09:44:01 +0100
Subject: [PATCH] get/set environment

---
 boa/src/builtins/function_object.rs | 46 +++++++++++++++++++++++++----
 boa/src/exec/mod.rs                 | 37 +++++++++++++++++++++--
 2 files changed, 75 insertions(+), 8 deletions(-)

diff --git a/boa/src/builtins/function_object.rs b/boa/src/builtins/function_object.rs
index 895c12e4bb5..018ea041425 100644
--- a/boa/src/builtins/function_object.rs
+++ b/boa/src/builtins/function_object.rs
@@ -37,8 +37,7 @@ pub enum ConstructorKind {
 #[derive(Debug, Copy, Clone)]
 pub enum ThisMode {
     Lexical,
-    Strict,
-    Global,
+    NonLexical,
 }
 
 /// FunctionBody is Boa specific, it will either be Rust code or JavaScript code (Block Node)
@@ -68,8 +67,8 @@ pub struct Function {
     pub params: Vec<FormalParameter>,
     /// This Mode
     pub this_mode: ThisMode,
-    /// Reference to the current Environment Record
-    pub environment: Environment,
+    // Environment
+    pub environment: Option<Environment>,
 }
 
 impl Function {
@@ -108,7 +107,7 @@ impl Function {
             function_kind: kind,
             is_constructor: needs_construct,
             body,
-            environment: realm.environment.get_current_environment().clone(),
+            environment: None,
             params: parameter_list,
             this_mode,
         };
@@ -120,6 +119,43 @@ impl Function {
         func.define_own_property(String::from("length"), length_property);
         func
     }
+
+    /// Sets the current environment on this function object
+    ///
+    /// This should be set after creating struct instance.
+    /// Environment can't be an internal slot due to it not being a JSValue
+    pub fn set_environment(&mut self, env: Environment) {
+        self.environment = Some(env);
+    }
+
+    /// Fetches the current environment on this function.
+    ///
+    /// The environment should be a Function Declarative Record
+    ///
+    /// It should exist, if not it will panic
+    pub fn get_environment(&self) -> Environment {
+        match self.environment {
+            Some(v) => v,
+            None => panic!("No environment set on Function!"),
+        }
+    }
+
+    /// This will handle calls for both ordinary and built-in functions
+    ///
+    /// <https://tc39.es/ecma262/#sec-ecmascript-function-objects-call-thisargument-argumentslist>
+    pub fn call(
+        &self,
+        this: &Value,
+        args_list: &Vec<Value>,
+        interpreter: &mut Interpreter,
+    ) -> ResultValue {
+        // Is this a built-in function?
+        if let FunctionBody::BuiltIn(func) = self.body {
+            return func(this, args_list, interpreter);
+        }
+
+        Ok(undefined())
+    }
 }
 
 unsafe impl gc::Trace for Function {
diff --git a/boa/src/exec/mod.rs b/boa/src/exec/mod.rs
index 678a3e14e35..9b04f3f4249 100644
--- a/boa/src/exec/mod.rs
+++ b/boa/src/exec/mod.rs
@@ -5,6 +5,7 @@ use crate::{
     builtins::{
         array,
         function::{create_unmapped_arguments_object, Function, RegularFunction},
+        function_object::{Function as FunctionObject, FunctionBody, FunctionKind, ThisMode},
         object::{
             internal_methods_trait::ObjectInternalMethods, ObjectKind, INSTANCE_PROTOTYPE,
             PROTOTYPE,
@@ -256,20 +257,50 @@ impl Executor for Interpreter {
                 Ok(array)
             }
             Node::FunctionDecl(ref name, ref args, ref expr) => {
-                let function =
-                    Function::RegularFunc(RegularFunction::new(*expr.clone(), args.to_vec()));
-                let val = Gc::new(ValueData::Function(Box::new(GcCell::new(function))));
+                // Todo: Function.prototype doesn't exist yet, so the prototype right now is the Object.prototype
+                let proto = &self
+                    .realm
+                    .environment
+                    .get_global_object()
+                    .expect("Could not get the global object")
+                    .get_field_slice("Object")
+                    .get_field_slice("Prototype");
+
+                let func = FunctionObject::create_ordinary(
+                    proto.clone(),
+                    args.clone(), // TODO: args shouldn't need to be a reference it should be passed by value
+                    FunctionBody::Ordinary(*expr.clone()),
+                    ThisMode::Lexical,
+                    &mut self.realm,
+                    FunctionKind::Normal,
+                );
+
+                let val = Gc::new(ValueData::FunctionObj(Box::new(func)));
+
+                // Create a new function environment
+                let func_env = new_function_environment(
+                    val.clone(),
+                    Gc::new(ValueData::Undefined),
+                    Some(self.realm.environment.get_current_environment().clone()),
+                );
+
+                // Set the environment in an internal slot
+                val.borrow().set_internal_slot("environment", func_env);
+
+                // Set the name and assign it in the current environment
                 if name.is_some() {
                     self.realm.environment.create_mutable_binding(
                         name.clone().expect("No name was supplied"),
                         false,
                         VariableScope::Function,
                     );
+
                     self.realm.environment.initialize_binding(
                         name.as_ref().expect("Could not get name as reference"),
                         val.clone(),
                     )
                 }
+
                 Ok(val)
             }
             Node::ArrowFunctionDecl(ref args, ref expr) => {