Editorial: Declarative Env Rec has field [[Bindings]]

... that is a List of bindings (without being specific yet about what a binding is).
tc39 · Apr 20, 2023 · 24b2f6e · 24b2f6e
1 parent 5f795bb
commit 24b2f6e
Showing 1 changed file with 44 additions and 14 deletions.
diff --git a/spec.html b/spec.html
@@ -9989,6 +9989,33 @@ <h1>The Environment Record Type Hierarchy</h1>
       <emu-clause id="sec-declarative-environment-records">
         <h1>Declarative Environment Records</h1>
         <p>Each <dfn variants="Declarative Environment Records">Declarative Environment Record</dfn> is associated with an ECMAScript program scope containing variable, constant, let, class, module, import, and/or function declarations. A Declarative Environment Record binds the set of identifiers defined by the declarations contained within its scope.</p>
+        <p>Declarative Environment Records have the additional fields listed in <emu-xref href="#table-additional-fields-of-declarative-environment-records"></emu-xref>.</p>
+        <emu-table id="table-additional-fields-of-declarative-environment-records" caption="Additional Fields of Declarative Environment Records">
+          <table>
+            <tr>
+              <th>
+                Field Name
+              </th>
+              <th>
+                Value
+              </th>
+              <th>
+                Meaning
+              </th>
+            </tr>
+            <tr>
+              <td>
+                [[Bindings]]
+              </td>
+              <td>
+                a List of bindings
+              </td>
+              <td>
+                Satisfies the invariant that no two bindings in [[Bindings]] are bindings for the same name.
+              </td>
+            </tr>
+          </table>
+        </emu-table>
         <p>The behaviour of the concrete specification methods for Declarative Environment Records is defined by the following algorithms.</p>
 
         <emu-clause id="sec-declarative-environment-records-hasbinding-n" type="concrete method">
@@ -10005,7 +10032,7 @@ <h1>
             <dd>It determines if the argument identifier is one of the identifiers bound by the record.</dd>
           </dl>
           <emu-alg>
-            1. If _envRec_ has a binding for _N_, return *true*.
+            1. If _envRec_.[[Bindings]] contains a binding for _N_, return *true*.
             1. Return *false*.
           </emu-alg>
         </emu-clause>
@@ -10027,7 +10054,7 @@ <h1>
           <emu-alg>
             1. Assert: _envRec_.HasBinding(_N_) is *false*.
             1. Let _binding_ be a mutable binding for _N_ and record that it is uninitialized. If _D_ is *true*, record that the newly created binding may be deleted by a subsequent DeleteBinding call.
-            1. Add _binding_ to _envRec_.
+            1. Append _binding_ to _envRec_.[[Bindings]].
             1. Return ~unused~.
           </emu-alg>
         </emu-clause>
@@ -10049,7 +10076,7 @@ <h1>
           <emu-alg>
             1. Assert: _envRec_.HasBinding(_N_) is *false*.
             1. Let _binding_ be an immutable binding for _N_ and record that it is uninitialized. If _S_ is *true*, record that the newly created binding is a strict binding.
-            1. Add _binding_ to _envRec_.
+            1. Append _binding_ to _envRec_.[[Bindings]].
             1. Return ~unused~.
           </emu-alg>
         </emu-clause>
@@ -10070,7 +10097,7 @@ <h1>
           </dl>
           <emu-alg>
             1. Assert: _envRec_.HasBinding(_N_) is *true*.
-            1. Let _binding_ be the binding for _N_ in _envRec_.
+            1. Let _binding_ be the binding for _N_ in _envRec_.[[Bindings]].
             1. Assert: _binding_ is uninitialized.
             1. Set the bound value of _binding_ to _V_.
             1. <emu-not-ref>Record</emu-not-ref> that _binding_ has been initialized.
@@ -10099,7 +10126,7 @@ <h1>
               1. Perform ! _envRec_.CreateMutableBinding(_N_, *true*).
               1. Perform ! _envRec_.InitializeBinding(_N_, _V_).
               1. Return ~unused~.
-            1. Let _binding_ be the binding for _N_ in _envRec_.
+            1. Let _binding_ be the binding for _N_ in _envRec_.[[Bindings]].
             1. If _binding_ is a strict binding, set _S_ to *true*.
             1. If _binding_ has not yet been initialized, then
               1. Throw a *ReferenceError* exception.
@@ -10132,7 +10159,7 @@ <h1>
           </dl>
           <emu-alg>
             1. Assert: _envRec_.HasBinding(_N_) is *true*.
-            1. Let _binding_ be the binding for _N_ in _envRec_.
+            1. Let _binding_ be the binding for _N_ in _envRec_.[[Bindings]].
             1. If _binding_ is an uninitialized binding, throw a *ReferenceError* exception.
             1. Return the value currently bound in _binding_.
           </emu-alg>
@@ -10153,9 +10180,9 @@ <h1>
           </dl>
           <emu-alg>
             1. Assert: _envRec_.HasBinding(_N_) is *true*.
-            1. Let _binding_ be the binding for _N_ in _envRec_.
+            1. Let _binding_ be the binding for _N_ in _envRec_.[[Bindings]].
             1. If _binding_ cannot be deleted, return *false*.
-            1. Remove _binding_ from _envRec_.
+            1. Remove _binding_ from _envRec_.[[Bindings]].
             1. Return *true*.
           </emu-alg>
         </emu-clause>
@@ -11182,7 +11209,7 @@ <h1>
           <emu-alg>
             1. Assert: _S_ is *true*.
             1. Assert: _envRec_.HasBinding(_N_) is *true*.
-            1. Let _binding_ be the binding for _N_ in _envRec_.
+            1. Let _binding_ be the binding for _N_ in _envRec_.[[Bindings]].
             1. If _binding_ is an indirect binding, then
               1. Let _M_ and _N2_ be the indirection values provided when this binding for _N_ was created.
               1. Let _targetEnv_ be _M_.[[Environment]].
@@ -11248,7 +11275,7 @@ <h1>
             1. Assert: _envRec_.HasBinding(_N_) is *false*.
             1. Assert: When _M_.[[Environment]] is instantiated, it will have a direct binding for _N2_.
             1. Let _binding_ be an immutable indirect binding for _N_ that references _M_ and _N2_ as its target binding and record that the binding is initialized.
-            1. Add _binding_ to _envRec_.
+            1. Append _binding_ to _envRec_.[[Bindings]].
             1. Return ~unused~.
           </emu-alg>
         </emu-clause>
@@ -11290,7 +11317,8 @@ <h1>
         <dl class="header">
         </dl>
         <emu-alg>
-          1. Let _env_ be a new Declarative Environment Record containing no bindings.
+          1. Let _env_ be a new Declarative Environment Record.
+          1. Set _env_.[[Bindings]] to « ».
           1. Set _env_.[[OuterEnv]] to _E_.
           1. Return _env_.
         </emu-alg>
@@ -11325,7 +11353,8 @@ <h1>
         <dl class="header">
         </dl>
         <emu-alg>
-          1. Let _env_ be a new Function Environment Record containing no bindings.
+          1. Let _env_ be a new Function Environment Record.
+          1. Set _env_.[[Bindings]] to « ».
           1. Set _env_.[[FunctionObject]] to _F_.
           1. If _F_.[[ThisMode]] is ~lexical~, set _env_.[[ThisBindingStatus]] to ~lexical~.
           1. Else, set _env_.[[ThisBindingStatus]] to ~uninitialized~.
@@ -11366,7 +11395,8 @@ <h1>
         <dl class="header">
         </dl>
         <emu-alg>
-          1. Let _env_ be a new Module Environment Record containing no bindings.
+          1. Let _env_ be a new Module Environment Record.
+          1. Set _env_.[[Bindings]] to « ».
           1. Set _env_.[[OuterEnv]] to _E_.
           1. Return _env_.
         </emu-alg>
@@ -48609,7 +48639,7 @@ <h1>Changes to BlockDeclarationInstantiation</h1>
         <p>During BlockDeclarationInstantiation the following steps are performed in place of step <emu-xref href="#step-blockdeclarationinstantiation-initializebinding"></emu-xref>:</p>
         <emu-alg replaces-step="step-blockdeclarationinstantiation-initializebinding">
           1. Perform the following steps:
-            1. Let _binding_ be the binding for _fn_ in _env_.
+            1. Let _binding_ be the binding for _fn_ in _env_.[[Bindings]].
             1. If _binding_ is an uninitialized binding, then
               1. Perform ! _env_.InitializeBinding(_fn_, _fo_).
             1. Else,