Implement generator execution (#1790)

This Pull Request fixes/closes #1559.

It changes the following:

- Implement GeneratorFunction Objects
- Implement Generator Objects
- Implement generator execution in vm
- Create `FormalParameterList` to remove duplicate checks on function parameters 
- Refactor  `MethodDefinition` on object literals

boa_engine/src/builtins/function/arguments.rs

@@ -4,7 +4,7 @@ use crate::{
     object::{JsObject, ObjectData},
     property::PropertyDescriptor,
     symbol::{self, WellKnownSymbols},
-    syntax::ast::node::FormalParameter,
+    syntax::ast::node::FormalParameterList,
     Context, JsValue,
 };
 use boa_gc::{Finalize, Gc, Trace};
@@ -147,7 +147,7 @@ impl Arguments {
     /// <https://tc39.es/ecma262/#sec-createmappedargumentsobject>
     pub(crate) fn create_mapped_arguments_object(
         func: &JsObject,
-        formals: &[FormalParameter],
+        formals: &FormalParameterList,
         arguments_list: &[JsValue],
         env: &Gc<DeclarativeEnvironment>,
         context: &mut Context,
@@ -199,7 +199,7 @@ impl Arguments {
 
         let mut bindings = FxHashMap::default();
         let mut property_index = 0;
-        'outer: for formal in formals {
+        'outer: for formal in formals.parameters.iter() {
             for name in formal.names() {
                 if property_index >= len {
                     break 'outer;

boa_engine/src/builtins/function/mod.rs

@@ -175,7 +175,11 @@ pub enum Function {
         constructor: bool,
         captures: Captures,
     },
-    VmOrdinary {
+    Ordinary {
+        code: Gc<crate::vm::CodeBlock>,
+        environments: DeclarativeEnvironmentStack,
+    },
+    Generator {
         code: Gc<crate::vm::CodeBlock>,
         environments: DeclarativeEnvironmentStack,
     },
@@ -192,7 +196,7 @@ impl Function {
     pub fn is_constructor(&self) -> bool {
         match self {
             Self::Native { constructor, .. } | Self::Closure { constructor, .. } => *constructor,
-            Self::VmOrdinary { code, .. } => code.constructor,
+            Self::Ordinary { code, .. } | Self::Generator { code, .. } => code.constructor,
         }
     }
 }
@@ -454,11 +458,15 @@ impl BuiltInFunctionObject {
                 },
                 Some(name),
             ) => Ok(format!("function {name}() {{\n  [native Code]\n}}").into()),
-            (Function::VmOrdinary { .. }, Some(name)) if name.is_empty() => {
+            (Function::Ordinary { .. }, Some(name)) if name.is_empty() => {
                 Ok("[Function (anonymous)]".into())
             }
-            (Function::VmOrdinary { .. }, Some(name)) => Ok(format!("[Function: {name}]").into()),
-            (Function::VmOrdinary { .. }, None) => Ok("[Function (anonymous)]".into()),
+            (Function::Ordinary { .. }, Some(name)) => Ok(format!("[Function: {name}]").into()),
+            (Function::Ordinary { .. }, None) => Ok("[Function (anonymous)]".into()),
+            (Function::Generator { .. }, Some(name)) => {
+                Ok(format!("[Function*: {}]", &name).into())
+            }
+            (Function::Generator { .. }, None) => Ok("[Function* (anonymous)]".into()),
             _ => Ok("TODO".into()),
         }
     }