Expose get_this_binding as an environment record trait method

src/lib/environment/environment_record_trait.rs

@@ -9,7 +9,7 @@
 //! There are 5 Environment record kinds. They all have methods in common, these are implemented as a the `EnvironmentRecordTrait`
 //!
 use crate::{
-    builtins::value::Value,
+    builtins::value::{self, Value},
     environment::lexical_environment::{Environment, EnvironmentType},
 };
 use gc::{Finalize, Trace};
@@ -60,6 +60,11 @@ pub trait EnvironmentRecordTrait: Debug + Trace + Finalize {
     /// Return true if it does and false if it does not.
     fn has_this_binding(&self) -> bool;
 
+    fn get_this_binding(&self) -> Value {
+        debug_assert!(self.has_this_binding());
+        value::undefined()
+    }
+
     /// Determine if an Environment Record establishes a super method binding.
     /// Return true if it does and false if it does not.
     fn has_super_binding(&self) -> bool;

src/lib/environment/function_environment_record.rs

@@ -75,21 +75,6 @@ impl FunctionEnvironmentRecord {
             }
         }
     }
-
-    pub fn get_this_binding(&self) -> Value {
-        match self.this_binding_status {
-            BindingStatus::Lexical => {
-                // TODO: change this when error handling comes into play
-                panic!("There is no this for a lexical function record");
-            }
-            BindingStatus::Uninitialized => {
-                // TODO: change this when error handling comes into play
-                panic!("Reference Error: Unitialised binding for this function");
-            }
-
-            BindingStatus::Initialized => self.this_value.clone(),
-        }
-    }
 }
 
 impl EnvironmentRecordTrait for FunctionEnvironmentRecord {
@@ -221,6 +206,21 @@ impl EnvironmentRecordTrait for FunctionEnvironmentRecord {
         }
     }
 
+    fn get_this_binding(&self) -> Value {
+        match self.this_binding_status {
+            BindingStatus::Lexical => {
+                // TODO: change this when error handling comes into play
+                panic!("There is no this for a lexical function record");
+            }
+            BindingStatus::Uninitialized => {
+                // TODO: change this when error handling comes into play
+                panic!("Reference Error: Unitialised binding for this function");
+            }
+
+            BindingStatus::Initialized => self.this_value.clone(),
+        }
+    }
+
     fn with_base_object(&self) -> Value {
         Gc::new(ValueData::Undefined)
     }

src/lib/environment/global_environment_record.rs

@@ -29,10 +29,6 @@ pub struct GlobalEnvironmentRecord {
 }
 
 impl GlobalEnvironmentRecord {
-    pub fn get_this_binding(&self) -> Value {
-        self.global_this_binding.clone()
-    }
-
     pub fn has_var_declaration(&self, name: &str) -> bool {
         self.var_names.contains(name)
     }
@@ -166,6 +162,10 @@ impl EnvironmentRecordTrait for GlobalEnvironmentRecord {
         true
     }
 
+    fn get_this_binding(&self) -> Value {
+        self.global_this_binding.clone()
+    }
+
     fn has_super_binding(&self) -> bool {
         false
     }