Allow constants on namespaces

Closes #440.

Author: domenic

index.bs

@@ -4717,9 +4717,9 @@ associated behaviors.
 A namespace is a specification of a set of
 <dfn id="dfn-namespace-member" export lt="namespace member">namespace members</dfn>
 (matching <emu-nt><a href="#prod-NamespaceMembers">NamespaceMembers</a></emu-nt>), which are the
-[=regular operations=] and [=read only=] [=regular attributes=] that appear between the braces in
-the namespace declaration. These operations and attributes describe the behaviors packaged into the
-namespace.
+[=regular operations=], [=read only=] [=regular attributes=], and [=constants=] that appear between
+the braces in the namespace declaration. These operations and attributes describe the behaviors
+packaged into the namespace.
 
 As with interfaces, the IDL for namespaces can be split into multiple parts by using
 <dfn id="dfn-partial-namespace" export>partial namespace</dfn> definitions
@@ -4769,6 +4769,7 @@ Of the extended attributes defined in this specification, only the [{{CrossOrigi
     NamespaceMember :
         RegularOperation
         "readonly" AttributeRest
+        Const
 </pre>
 
 <div class="example" id="example-namespace">
@@ -11681,8 +11682,8 @@ on the single object that [=implements=] the interface,
 when an interface is declared with the [{{Global}}] [=extended attribute=].
 
 <div algorithm>
-    To <dfn>define the constants</dfn> of [=interface=] or [=callback interface=] |definition| on
-    |target|, given [=Realm=] |realm|, run the following steps:
+    To <dfn>define the constants</dfn> of [=interface=], [=callback interface=], or [=namespace=]
+    |definition| on |target|, given [=Realm=] |realm|, run the following steps:
 
     1.  [=list/For each=] [=constant=] |const| that is a [=member=] of |definition|:
         1.  If |const| is not [=exposed=] in |realm|, then [=iteration/continue=].
@@ -14245,6 +14246,7 @@ The characteristics of a namespace object are described in [[#namespace-object]]
     1.  Let |namespaceObject| be [=!=] [$OrdinaryObjectCreate$](|realm|.\[[Intrinsics]].[[{{%Object.prototype%}}]]).
     1.  [=Define the regular attributes=] of |namespace| on |namespaceObject| given |realm|.
     1.  [=Define the regular operations=] of |namespace| on |namespaceObject| given |realm|.
+    1.  [=Define the constants=] of |namespace| on |namespaceObject| given |realm|.
     1.  For each [=exposed=] [=interface=] |interface| which has the [{{LegacyNamespace}}] extended
         attribute with the identifier of |namespace| as its argument,
         1.  Let |id| be |interface|'s [=identifier=].