From 074d05db1dbc1439dc89c17a74aa9c5ebb0c7b8b Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 6 Apr 2023 12:44:18 -0400
Subject: [PATCH 01/18] feat: allow adding additional members to production
 parse methods

---
 lib/productions/callback-interface.js |  9 +++++++--
 lib/productions/container.js          | 17 ++++++++++++++++-
 lib/productions/dictionary.js         |  5 +++--
 lib/productions/interface.js          |  7 ++++++-
 lib/productions/mixin.js              |  6 ++++--
 lib/productions/namespace.js          |  4 +++-
 6 files changed, 39 insertions(+), 9 deletions(-)

diff --git a/lib/productions/callback-interface.js b/lib/productions/callback-interface.js
index da9dc96f..293b4a83 100644
--- a/lib/productions/callback-interface.js
+++ b/lib/productions/callback-interface.js
@@ -5,8 +5,12 @@ import { Constant } from "./constant.js";
 export class CallbackInterface extends Container {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
+   * @param {*} callback
+   * @param {object} [options]
+   * @param {boolean} [options.inheritable]
+   * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    */
-  static parse(tokeniser, callback, { partial = null } = {}) {
+  static parse(tokeniser, callback, { inheritable, extMembers = [] } = {}) {
     const tokens = { callback };
     tokens.base = tokeniser.consume("interface");
     if (!tokens.base) {
@@ -16,8 +20,9 @@ export class CallbackInterface extends Container {
       tokeniser,
       new CallbackInterface({ source: tokeniser.source, tokens }),
       {
-        inheritable: !partial,
+        inheritable: !!inheritable,
         allowedMembers: [
+          ...extMembers,
           [Constant.parse],
           [Operation.parse, { regular: true }],
         ],
diff --git a/lib/productions/container.js b/lib/productions/container.js
index d52dc509..ed628aae 100644
--- a/lib/productions/container.js
+++ b/lib/productions/container.js
@@ -16,11 +16,26 @@ function inheritance(tokeniser) {
   return { colon, inheritance };
 }
 
+/**
+ * Parser callback.
+ * @callback parserCallback
+ * @param {import("../tokeniser.js").Tokeniser} tokeniser
+ * @param {...*} args
+ */
+
+/**
+ * A parser callback and optional option object.
+ * @typedef AllowedMember
+ * @type {[parserCallback, object?]}
+ */
+
 export class Container extends Base {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {*} instance TODO: This should be {T extends Container}, but see https://github.com/microsoft/TypeScript/issues/4628
-   * @param {*} args
+   * @param {object} args
+   * @param {boolean} args.inheritable
+   * @param {AllowedMember[]} args.allowedMembers
    */
   static parse(tokeniser, instance, { inheritable, allowedMembers }) {
     const { tokens, type } = instance;
diff --git a/lib/productions/dictionary.js b/lib/productions/dictionary.js
index fa55d979..57462c4c 100644
--- a/lib/productions/dictionary.js
+++ b/lib/productions/dictionary.js
@@ -5,9 +5,10 @@ export class Dictionary extends Container {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {object} [options]
+   * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    * @param {import("../tokeniser.js").Token} [options.partial]
    */
-  static parse(tokeniser, { partial } = {}) {
+  static parse(tokeniser, { extMembers = [], partial } = {}) {
     const tokens = { partial };
     tokens.base = tokeniser.consume("dictionary");
     if (!tokens.base) {
@@ -18,7 +19,7 @@ export class Dictionary extends Container {
       new Dictionary({ source: tokeniser.source, tokens }),
       {
         inheritable: !partial,
-        allowedMembers: [[Field.parse]],
+        allowedMembers: [...extMembers, [Field.parse]],
       }
     );
   }
diff --git a/lib/productions/interface.js b/lib/productions/interface.js
index e22b54a2..f361e527 100644
--- a/lib/productions/interface.js
+++ b/lib/productions/interface.js
@@ -34,8 +34,12 @@ function static_member(tokeniser) {
 export class Interface extends Container {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
+   * @param {Token} base
+   * @param {object} [options]
+   * @param {import("./container.js").AllowedMember[]} [options.extMembers]
+   * @param {import("../tokeniser.js").Token|null} [options.partial]
    */
-  static parse(tokeniser, base, { partial = null } = {}) {
+  static parse(tokeniser, base, { extMembers = [], partial = null } = {}) {
     const tokens = { partial, base };
     return Container.parse(
       tokeniser,
@@ -43,6 +47,7 @@ export class Interface extends Container {
       {
         inheritable: !partial,
         allowedMembers: [
+          ...extMembers,
           [Constant.parse],
           [Constructor.parse],
           [static_member],
diff --git a/lib/productions/mixin.js b/lib/productions/mixin.js
index c3094e7c..5108efdb 100644
--- a/lib/productions/mixin.js
+++ b/lib/productions/mixin.js
@@ -11,9 +11,10 @@ export class Mixin extends Container {
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {Token} base
    * @param {object} [options]
-   * @param {Token} [options.partial]
+   * @param {import("./container.js").AllowedMember[]} [options.extMembers]
+   * @param {import("../tokeniser.js").Token} [options.partial]
    */
-  static parse(tokeniser, base, { partial } = {}) {
+  static parse(tokeniser, base, { extMembers = [], partial } = {}) {
     const tokens = { partial, base };
     tokens.mixin = tokeniser.consume("mixin");
     if (!tokens.mixin) {
@@ -24,6 +25,7 @@ export class Mixin extends Container {
       new Mixin({ source: tokeniser.source, tokens }),
       {
         allowedMembers: [
+          ...extMembers,
           [Constant.parse],
           [stringifier],
           [Attribute.parse, { noInherit: true }],
diff --git a/lib/productions/namespace.js b/lib/productions/namespace.js
index ef7c35f5..34fa6e49 100644
--- a/lib/productions/namespace.js
+++ b/lib/productions/namespace.js
@@ -9,9 +9,10 @@ export class Namespace extends Container {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {object} [options]
+   * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    * @param {import("../tokeniser.js").Token} [options.partial]
    */
-  static parse(tokeniser, { partial } = {}) {
+  static parse(tokeniser, { extMembers = [], partial } = {}) {
     const tokens = { partial };
     tokens.base = tokeniser.consume("namespace");
     if (!tokens.base) {
@@ -22,6 +23,7 @@ export class Namespace extends Container {
       new Namespace({ source: tokeniser.source, tokens }),
       {
         allowedMembers: [
+          ...extMembers,
           [Attribute.parse, { noInherit: true, readonly: true }],
           [Constant.parse],
           [Operation.parse, { regular: true }],

From bb9f3b42dc356ad6e0e85ee02fcfdd7c899e70c6 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Wed, 12 Apr 2023 11:33:47 -0400
Subject: [PATCH 02/18] feat: add 'extensions' option for extending existing
 productions

---
 lib/webidl2.js                                | 54 +++++++++++++------
 test/extensions.js                            | 20 +++++++
 .../baseline/attr-on-callback-interface.json  | 30 +++++++++++
 .../baseline/namespace-attribute.json         | 30 +++++++++++
 .../idl/attr-on-callback-interface.webidl     |  3 ++
 .../extensions/idl/namespace-attribute.webidl |  3 ++
 test/util/collect.js                          |  3 +-
 7 files changed, 126 insertions(+), 17 deletions(-)
 create mode 100644 test/extensions.js
 create mode 100644 test/extensions/baseline/attr-on-callback-interface.json
 create mode 100644 test/extensions/baseline/namespace-attribute.json
 create mode 100644 test/extensions/idl/attr-on-callback-interface.webidl
 create mode 100644 test/extensions/idl/namespace-attribute.webidl

diff --git a/lib/webidl2.js b/lib/webidl2.js
index 6129879b..c4841d45 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -12,11 +12,22 @@ import { CallbackInterface } from "./productions/callback-interface.js";
 import { autoParenter } from "./productions/helpers.js";
 import { Eof } from "./productions/token.js";
 
+/** @typedef {'callback-interface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
+/** @typedef {Object.<'extMembers', import("./container.js").AllowedMember[]>} Extension */
+
 /**
- * @param {Tokeniser} tokeniser
+ * Parser options.
+ * @typedef ParserOptions
  * @param {object} options
+ * @param {string} [options.sourceName]
  * @param {boolean} [options.concrete]
  * @param {Function[]} [options.productions]
+ * @param {Object.<ExtendableInterfaces, Extension>} [options.extensions]
+ */
+
+/**
+ * @param {Tokeniser} tokeniser
+ * @param {ParserOptions} options
  */
 function parseByTokens(tokeniser, options) {
   const source = tokeniser.source;
@@ -33,7 +44,9 @@ function parseByTokens(tokeniser, options) {
     const callback = consume("callback");
     if (!callback) return;
     if (tokeniser.probe("interface")) {
-      return CallbackInterface.parse(tokeniser, callback);
+      return CallbackInterface.parse(tokeniser, callback, {
+        ...options?.extensions?.["callback-interface"],
+      });
     }
     return CallbackFunction.parse(tokeniser, callback);
   }
@@ -41,20 +54,32 @@ function parseByTokens(tokeniser, options) {
   function interface_(opts) {
     const base = consume("interface");
     if (!base) return;
-    const ret =
-      Mixin.parse(tokeniser, base, opts) ||
-      Interface.parse(tokeniser, base, opts) ||
-      error("Interface has no proper body");
-    return ret;
+    return (
+      Mixin.parse(tokeniser, base, {
+        ...opts,
+        ...options?.extensions?.mixin,
+      }) ||
+      Interface.parse(tokeniser, base, {
+        ...opts,
+        ...options?.extensions?.interface,
+      }) ||
+      error("Interface has no proper body")
+    );
   }
 
   function partial() {
     const partial = consume("partial");
     if (!partial) return;
     return (
-      Dictionary.parse(tokeniser, { partial }) ||
+      Dictionary.parse(tokeniser, {
+        partial,
+        ...options?.extensions?.dictionary,
+      }) ||
       interface_({ partial }) ||
-      Namespace.parse(tokeniser, { partial }) ||
+      Namespace.parse(tokeniser, {
+        partial,
+        ...options?.extensions?.namespace,
+      }) ||
       error("Partial doesn't apply to anything")
     );
   }
@@ -73,11 +98,11 @@ function parseByTokens(tokeniser, options) {
       callback() ||
       interface_() ||
       partial() ||
-      Dictionary.parse(tokeniser) ||
+      Dictionary.parse(tokeniser, { ...options?.extensions?.dictionary }) ||
       Enum.parse(tokeniser) ||
       Typedef.parse(tokeniser) ||
       Includes.parse(tokeniser) ||
-      Namespace.parse(tokeniser)
+      Namespace.parse(tokeniser, { ...options?.extensions?.namespace })
     );
   }
 
@@ -100,6 +125,7 @@ function parseByTokens(tokeniser, options) {
     }
     return defs;
   }
+
   const res = definitions();
   if (tokeniser.position < source.length) error("Unrecognised tokens");
   return res;
@@ -107,11 +133,7 @@ function parseByTokens(tokeniser, options) {
 
 /**
  * @param {string} str
- * @param {object} [options]
- * @param {*} [options.sourceName]
- * @param {boolean} [options.concrete]
- * @param {Function[]} [options.productions]
- * @return {import("./productions/base.js").Base[]}
+ * @param {ParserOptions} [options]
  */
 export function parse(str, options = {}) {
   const tokeniser = new Tokeniser(str);
diff --git a/test/extensions.js b/test/extensions.js
new file mode 100644
index 00000000..5033b8da
--- /dev/null
+++ b/test/extensions.js
@@ -0,0 +1,20 @@
+import { collect } from "./util/collect.js";
+import expect from "expect";
+import { Attribute } from "../lib/productions/attribute.js";
+
+const extensions = {
+  "callback-interface": {
+    extMembers: [[Attribute.parse]],
+  },
+  namespace: {
+    extMembers: [[Attribute.parse, { readonly: false }]],
+  },
+};
+
+describe("Parses all of the IDLs that require extensions", () => {
+  for (const test of collect("extensions", { extensions })) {
+    it(`should produce the same AST for ${test.path}`, () => {
+      expect(test.diff()).toBeFalsy();
+    });
+  }
+});
diff --git a/test/extensions/baseline/attr-on-callback-interface.json b/test/extensions/baseline/attr-on-callback-interface.json
new file mode 100644
index 00000000..25e73251
--- /dev/null
+++ b/test/extensions/baseline/attr-on-callback-interface.json
@@ -0,0 +1,30 @@
+[
+  {
+    "type": "callback interface",
+    "name": "TestCallbackInterface",
+    "inheritance": null,
+    "members": [
+      {
+        "type": "attribute",
+        "name": "foo",
+        "idlType": {
+          "type": "attribute-type",
+          "extAttrs": [],
+          "generic": "",
+          "nullable": false,
+          "union": false,
+          "idlType": "long"
+        },
+        "extAttrs": [],
+        "special": "",
+        "readonly": true
+      }
+    ],
+    "extAttrs": [],
+    "partial": false
+  },
+  {
+    "type": "eof",
+    "value": ""
+  }
+]
diff --git a/test/extensions/baseline/namespace-attribute.json b/test/extensions/baseline/namespace-attribute.json
new file mode 100644
index 00000000..cb829b8f
--- /dev/null
+++ b/test/extensions/baseline/namespace-attribute.json
@@ -0,0 +1,30 @@
+[
+  {
+    "type": "namespace",
+    "name": "WebrtcGlobalInformation",
+    "inheritance": null,
+    "members": [
+      {
+        "type": "attribute",
+        "name": "debugLevel",
+        "idlType": {
+          "type": "attribute-type",
+          "extAttrs": [],
+          "generic": "",
+          "nullable": false,
+          "union": false,
+          "idlType": "long"
+        },
+        "extAttrs": [],
+        "special": "",
+        "readonly": false
+      }
+    ],
+    "extAttrs": [],
+    "partial": false
+  },
+  {
+    "type": "eof",
+    "value": ""
+  }
+]
diff --git a/test/extensions/idl/attr-on-callback-interface.webidl b/test/extensions/idl/attr-on-callback-interface.webidl
new file mode 100644
index 00000000..112fa0c3
--- /dev/null
+++ b/test/extensions/idl/attr-on-callback-interface.webidl
@@ -0,0 +1,3 @@
+callback interface TestCallbackInterface {
+  readonly attribute long foo;
+};
diff --git a/test/extensions/idl/namespace-attribute.webidl b/test/extensions/idl/namespace-attribute.webidl
new file mode 100644
index 00000000..c7d09504
--- /dev/null
+++ b/test/extensions/idl/namespace-attribute.webidl
@@ -0,0 +1,3 @@
+namespace WebrtcGlobalInformation {
+  attribute long debugLevel;
+};
diff --git a/test/util/collect.js b/test/util/collect.js
index 7909f810..ef82ebbf 100644
--- a/test/util/collect.js
+++ b/test/util/collect.js
@@ -7,7 +7,7 @@ import { diff } from "jsondiffpatch";
  * Collects test items from the specified directory
  * @param {string} base
  */
-export function* collect(base, { expectError, raw } = {}) {
+export function* collect(base, { expectError, raw, extensions = {} } = {}) {
   const dir = new URL(join("..", base, "idl/"), import.meta.url);
   const idls = readdirSync(dir)
     .filter((it) => it.endsWith(".webidl"))
@@ -19,6 +19,7 @@ export function* collect(base, { expectError, raw } = {}) {
       const ast = parse(text, {
         concrete: true,
         sourceName: basename(path.pathname),
+        extensions,
       });
       const validation = validate(ast);
       if (validation) {

From 0a2b8600887062e163fb987c38e7ae96a97cecb8 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 10:32:51 -0400
Subject: [PATCH 03/18] fix: remove unnecessary spread operator

Co-authored-by: Kagami Sascha Rosylight <saschanaz@outlook.com>
---
 lib/webidl2.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index c4841d45..1bfc2762 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -98,7 +98,7 @@ function parseByTokens(tokeniser, options) {
       callback() ||
       interface_() ||
       partial() ||
-      Dictionary.parse(tokeniser, { ...options?.extensions?.dictionary }) ||
+      Dictionary.parse(tokeniser, options?.extensions?.dictionary) ||
       Enum.parse(tokeniser) ||
       Typedef.parse(tokeniser) ||
       Includes.parse(tokeniser) ||

From 491c5cf1d742f9642199d71191850423c9d84e3f Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 10:30:04 -0400
Subject: [PATCH 04/18] refactor: rename extension 'callback-interface' to
 callbackInterface

---
 lib/webidl2.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index 1bfc2762..515133fc 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -12,7 +12,7 @@ import { CallbackInterface } from "./productions/callback-interface.js";
 import { autoParenter } from "./productions/helpers.js";
 import { Eof } from "./productions/token.js";
 
-/** @typedef {'callback-interface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
+/** @typedef {'callbackInterface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
 /** @typedef {Object.<'extMembers', import("./container.js").AllowedMember[]>} Extension */
 
 /**
@@ -45,7 +45,7 @@ function parseByTokens(tokeniser, options) {
     if (!callback) return;
     if (tokeniser.probe("interface")) {
       return CallbackInterface.parse(tokeniser, callback, {
-        ...options?.extensions?.["callback-interface"],
+        ...options?.extensions?.callbackInterface,
       });
     }
     return CallbackFunction.parse(tokeniser, callback);

From 883ca3c33863745d75b2c202e1490266a39d5416 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 11:57:59 -0400
Subject: [PATCH 05/18] test: improve extension parsing tests

---
 test/extensions.js                            | 58 ++++++++++++++-----
 .../baseline/attr-on-callback-interface.json  | 30 ----------
 .../baseline/namespace-attribute.json         | 30 ----------
 .../idl/attr-on-callback-interface.webidl     |  3 -
 .../extensions/idl/namespace-attribute.webidl |  3 -
 5 files changed, 44 insertions(+), 80 deletions(-)
 delete mode 100644 test/extensions/baseline/attr-on-callback-interface.json
 delete mode 100644 test/extensions/baseline/namespace-attribute.json
 delete mode 100644 test/extensions/idl/attr-on-callback-interface.webidl
 delete mode 100644 test/extensions/idl/namespace-attribute.webidl

diff --git a/test/extensions.js b/test/extensions.js
index 5033b8da..ef017ba5 100644
--- a/test/extensions.js
+++ b/test/extensions.js
@@ -1,20 +1,50 @@
-import { collect } from "./util/collect.js";
+"use strict";
 import expect from "expect";
+
 import { Attribute } from "../lib/productions/attribute.js";
+import { parse } from "../lib/webidl2.js";
+import { IterableLike } from "../lib/productions/iterable.js";
+
+describe("Parse IDLs using custom extensions", () => {
+  ["callback interface", "dictionary"].forEach((type) => {
+    it(`Attribute on ${type}`, () => {
+      const customIdl = `${type} Foo {
+        attribute long bar;
+      };`;
 
-const extensions = {
-  "callback-interface": {
-    extMembers: [[Attribute.parse]],
-  },
-  namespace: {
-    extMembers: [[Attribute.parse, { readonly: false }]],
-  },
-};
+      // Convert to camel case
+      const key = type.replace(/ (.)/g, (m, c) => c.toUpperCase());
+      const result = parse(customIdl, {
+        concrete: true,
+        extensions: { [key]: { extMembers: [[Attribute.parse]] } },
+      });
+      expect(result[0].type).toBe(type);
+      expect(result[0].members[0].type).toBe("attribute");
+    });
+  });
+
+  it("Attribute (writable) on namespace", () => {
+    const customIdl = `namespace Foo {
+        attribute long bar;
+      };`;
+    const result = parse(customIdl, {
+      concrete: true,
+      extensions: { namespace: { extMembers: [[Attribute.parse]] } },
+    });
+    expect(result[0].type).toBe("namespace");
+    expect(result[0].members[0].type).toBe("attribute");
+    expect(result[0].members[0].readonly).toBe(false);
+  });
 
-describe("Parses all of the IDLs that require extensions", () => {
-  for (const test of collect("extensions", { extensions })) {
-    it(`should produce the same AST for ${test.path}`, () => {
-      expect(test.diff()).toBeFalsy();
+  it("Map-like on mixin", () => {
+    const customIdl = `interface mixin Foo {
+        readonly maplike<DOMString, unsigned long long>;
+      };`;
+    const result = parse(customIdl, {
+      concrete: true,
+      extensions: { mixin: { extMembers: [[IterableLike.parse]] } },
     });
-  }
+    expect(result[0].type).toBe("interface mixin");
+    expect(result[0].members[0].type).toBe("maplike");
+  });
 });
diff --git a/test/extensions/baseline/attr-on-callback-interface.json b/test/extensions/baseline/attr-on-callback-interface.json
deleted file mode 100644
index 25e73251..00000000
--- a/test/extensions/baseline/attr-on-callback-interface.json
+++ /dev/null
@@ -1,30 +0,0 @@
-[
-  {
-    "type": "callback interface",
-    "name": "TestCallbackInterface",
-    "inheritance": null,
-    "members": [
-      {
-        "type": "attribute",
-        "name": "foo",
-        "idlType": {
-          "type": "attribute-type",
-          "extAttrs": [],
-          "generic": "",
-          "nullable": false,
-          "union": false,
-          "idlType": "long"
-        },
-        "extAttrs": [],
-        "special": "",
-        "readonly": true
-      }
-    ],
-    "extAttrs": [],
-    "partial": false
-  },
-  {
-    "type": "eof",
-    "value": ""
-  }
-]
diff --git a/test/extensions/baseline/namespace-attribute.json b/test/extensions/baseline/namespace-attribute.json
deleted file mode 100644
index cb829b8f..00000000
--- a/test/extensions/baseline/namespace-attribute.json
+++ /dev/null
@@ -1,30 +0,0 @@
-[
-  {
-    "type": "namespace",
-    "name": "WebrtcGlobalInformation",
-    "inheritance": null,
-    "members": [
-      {
-        "type": "attribute",
-        "name": "debugLevel",
-        "idlType": {
-          "type": "attribute-type",
-          "extAttrs": [],
-          "generic": "",
-          "nullable": false,
-          "union": false,
-          "idlType": "long"
-        },
-        "extAttrs": [],
-        "special": "",
-        "readonly": false
-      }
-    ],
-    "extAttrs": [],
-    "partial": false
-  },
-  {
-    "type": "eof",
-    "value": ""
-  }
-]
diff --git a/test/extensions/idl/attr-on-callback-interface.webidl b/test/extensions/idl/attr-on-callback-interface.webidl
deleted file mode 100644
index 112fa0c3..00000000
--- a/test/extensions/idl/attr-on-callback-interface.webidl
+++ /dev/null
@@ -1,3 +0,0 @@
-callback interface TestCallbackInterface {
-  readonly attribute long foo;
-};
diff --git a/test/extensions/idl/namespace-attribute.webidl b/test/extensions/idl/namespace-attribute.webidl
deleted file mode 100644
index c7d09504..00000000
--- a/test/extensions/idl/namespace-attribute.webidl
+++ /dev/null
@@ -1,3 +0,0 @@
-namespace WebrtcGlobalInformation {
-  attribute long debugLevel;
-};

From aabbb9ed4baaec1c9a5d4459a0f15d80bc51960d Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 11:58:13 -0400
Subject: [PATCH 06/18] docs: fix up jsdoc definition for ParserOptions

---
 lib/webidl2.js | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index 515133fc..aa532426 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -13,16 +13,16 @@ import { autoParenter } from "./productions/helpers.js";
 import { Eof } from "./productions/token.js";
 
 /** @typedef {'callbackInterface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
-/** @typedef {Object.<'extMembers', import("./container.js").AllowedMember[]>} Extension */
+/** @typedef {Object.<'extMembers', import("./container.js").AllowedMember[] >} Extension */
+/** @typedef {Object.<[ExtendableInterfaces], Extension>} Extensions */
 
 /**
  * Parser options.
- * @typedef ParserOptions
- * @param {object} options
- * @param {string} [options.sourceName]
- * @param {boolean} [options.concrete]
- * @param {Function[]} [options.productions]
- * @param {Object.<ExtendableInterfaces, Extension>} [options.extensions]
+ * @typedef {Object} ParserOptions
+ * @property {string} [sourceName]
+ * @property {boolean} [concrete]
+ * @property {Function[]} [productions]
+ * @property {Extensions} [extensions]
  */
 
 /**

From e20190ec319038782ce4eb8325888e21518de274 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 14:19:33 -0400
Subject: [PATCH 07/18] test: remove use strict

---
 test/extensions.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/extensions.js b/test/extensions.js
index ef017ba5..06cd3e8a 100644
--- a/test/extensions.js
+++ b/test/extensions.js
@@ -1,4 +1,3 @@
-"use strict";
 import expect from "expect";
 
 import { Attribute } from "../lib/productions/attribute.js";

From 48c4dc2e1b221b80113cd1e1cfebb3d92088e731 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 15:08:19 -0400
Subject: [PATCH 08/18] test: merge extension test into custom-production

---
 test/custom-production.js | 59 +++++++++++++++++++++++++++++++++++++--
 test/extensions.js        | 49 --------------------------------
 2 files changed, 57 insertions(+), 51 deletions(-)
 delete mode 100644 test/extensions.js

diff --git a/test/custom-production.js b/test/custom-production.js
index 245fdec6..1f96a57e 100644
--- a/test/custom-production.js
+++ b/test/custom-production.js
@@ -1,7 +1,40 @@
-"use strict";
+import expect from "expect";
 
-import { expect } from "expect";
 import { parse, write } from "webidl2";
+import { Base } from "../lib/productions/base.js";
+import {
+  autoParenter,
+  type_with_extended_attributes,
+} from "../lib/productions/helpers.js";
+
+class CustomAttribute extends Base {
+  static parse(tokeniser) {
+    const start_position = tokeniser.position;
+    const tokens = {};
+    const ret = autoParenter(
+      new CustomAttribute({ source: tokeniser.source, tokens })
+    );
+    tokens.base = tokeniser.consumeIdentifier("custom");
+    if (!tokens.base) {
+      tokeniser.unconsume(start_position);
+      return;
+    }
+    ret.idlType =
+      type_with_extended_attributes(tokeniser, "attribute-type") ||
+      tokeniser.error("Attribute lacks a type");
+    tokens.name =
+      tokeniser.consumeKind("identifier") ||
+      tokeniser.error("Attribute lacks a name");
+    tokens.termination =
+      tokeniser.consume(";") ||
+      tokeniser.error("Unterminated attribute, expected `;`");
+    return ret.this;
+  }
+
+  get type() {
+    return "custom attribute";
+  }
+}
 
 describe("Writer template functions", () => {
   const customIdl = `
@@ -49,3 +82,25 @@ describe("Writer template functions", () => {
   const rewritten = write(result);
   expect(rewritten).toBe(customIdl);
 });
+
+describe("Parse IDLs using custom extensions", () => {
+  [
+    ["callback interface", "callbackInterface"],
+    ["dictionary", "dictionary"],
+    ["interface", "interface"],
+    ["interface mixin", "mixin"],
+    ["namespace", "namespace"],
+  ].forEach(([type, key]) => {
+    it(`Attribute on ${type}`, () => {
+      const customIdl = `${type} Foo {
+        custom long bar;
+      };`;
+      const result = parse(customIdl, {
+        concrete: true,
+        extensions: { [key]: { extMembers: [[CustomAttribute.parse]] } },
+      });
+      expect(result[0].type).toBe(type);
+      expect(result[0].members[0].type).toBe("custom attribute");
+    });
+  });
+});
diff --git a/test/extensions.js b/test/extensions.js
deleted file mode 100644
index 06cd3e8a..00000000
--- a/test/extensions.js
+++ /dev/null
@@ -1,49 +0,0 @@
-import expect from "expect";
-
-import { Attribute } from "../lib/productions/attribute.js";
-import { parse } from "../lib/webidl2.js";
-import { IterableLike } from "../lib/productions/iterable.js";
-
-describe("Parse IDLs using custom extensions", () => {
-  ["callback interface", "dictionary"].forEach((type) => {
-    it(`Attribute on ${type}`, () => {
-      const customIdl = `${type} Foo {
-        attribute long bar;
-      };`;
-
-      // Convert to camel case
-      const key = type.replace(/ (.)/g, (m, c) => c.toUpperCase());
-      const result = parse(customIdl, {
-        concrete: true,
-        extensions: { [key]: { extMembers: [[Attribute.parse]] } },
-      });
-      expect(result[0].type).toBe(type);
-      expect(result[0].members[0].type).toBe("attribute");
-    });
-  });
-
-  it("Attribute (writable) on namespace", () => {
-    const customIdl = `namespace Foo {
-        attribute long bar;
-      };`;
-    const result = parse(customIdl, {
-      concrete: true,
-      extensions: { namespace: { extMembers: [[Attribute.parse]] } },
-    });
-    expect(result[0].type).toBe("namespace");
-    expect(result[0].members[0].type).toBe("attribute");
-    expect(result[0].members[0].readonly).toBe(false);
-  });
-
-  it("Map-like on mixin", () => {
-    const customIdl = `interface mixin Foo {
-        readonly maplike<DOMString, unsigned long long>;
-      };`;
-    const result = parse(customIdl, {
-      concrete: true,
-      extensions: { mixin: { extMembers: [[IterableLike.parse]] } },
-    });
-    expect(result[0].type).toBe("interface mixin");
-    expect(result[0].members[0].type).toBe("maplike");
-  });
-});

From ca97d20114340bc316cc5588d8ce45ffe6587c2d Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Thu, 13 Apr 2023 16:18:55 -0400
Subject: [PATCH 09/18] test: replace customProduction with top-level
 CustomAttribute

---
 test/custom-production.js | 67 ++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 43 deletions(-)

diff --git a/test/custom-production.js b/test/custom-production.js
index 1f96a57e..5ada1068 100644
--- a/test/custom-production.js
+++ b/test/custom-production.js
@@ -34,53 +34,34 @@ class CustomAttribute extends Base {
   get type() {
     return "custom attribute";
   }
-}
 
-describe("Writer template functions", () => {
-  const customIdl = `
-    interface X {};
-    custom Y;
-  `;
+  write(w) {
+    const { parent } = this;
+    return w.ts.definition(
+      w.ts.wrap([
+        this.extAttrs.write(w),
+        w.token(this.tokens.base),
+        w.ts.type(this.idlType.write(w)),
+        w.name_token(this.tokens.name, { data: this, parent }),
+        w.token(this.tokens.termination),
+      ]),
+      { data: this, parent }
+    );
+  }
+}
 
-  /**
-   * @param {import("../lib/tokeniser").Tokeniser} tokeniser
-   */
-  const customProduction = (tokeniser) => {
-    const { position } = tokeniser;
-    const base = tokeniser.consumeIdentifier("custom");
-    if (!base) {
-      return;
-    }
-    const tokens = { base };
-    tokens.name = tokeniser.consumeKind("identifier");
-    tokens.termination = tokeniser.consume(";");
-    if (!tokens.name || !tokens.termination) {
-      tokeniser.unconsume(position);
-      return;
-    }
-    return {
-      type: "custom",
-      tokens,
-      /** @param {import("../lib/writer.js").Writer} w */
-      write(w) {
-        return w.ts.wrap([
-          w.token(this.tokens.base),
-          w.token(this.tokens.name),
-          w.token(this.tokens.termination),
-        ]);
-      },
-    };
-  };
+describe("Parse IDLs using custom productions", () => {
+  it("Parse and rewrite top-level custom attribute", () => {
+    const customIdl = "custom long bar;";
+    const result = parse(customIdl, {
+      productions: [CustomAttribute.parse],
+      concrete: true,
+    });
+    expect(result[0].type).toBe("custom attribute");
 
-  const result = parse(customIdl, {
-    productions: [customProduction],
-    concrete: true,
+    const rewritten = write(result);
+    expect(rewritten).toBe(customIdl);
   });
-  expect(result[0].type).toBe("interface");
-  expect(result[1].type).toBe("custom");
-
-  const rewritten = write(result);
-  expect(rewritten).toBe(customIdl);
 });
 
 describe("Parse IDLs using custom extensions", () => {

From 66e3862e2cca9ad30a3fe7cf655b5011023cdb34 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Mon, 17 Apr 2023 09:11:51 -0400
Subject: [PATCH 10/18] test: remove extension argument from collection utility

---
 test/util/collect.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/util/collect.js b/test/util/collect.js
index ef82ebbf..7909f810 100644
--- a/test/util/collect.js
+++ b/test/util/collect.js
@@ -7,7 +7,7 @@ import { diff } from "jsondiffpatch";
  * Collects test items from the specified directory
  * @param {string} base
  */
-export function* collect(base, { expectError, raw, extensions = {} } = {}) {
+export function* collect(base, { expectError, raw } = {}) {
   const dir = new URL(join("..", base, "idl/"), import.meta.url);
   const idls = readdirSync(dir)
     .filter((it) => it.endsWith(".webidl"))
@@ -19,7 +19,6 @@ export function* collect(base, { expectError, raw, extensions = {} } = {}) {
       const ast = parse(text, {
         concrete: true,
         sourceName: basename(path.pathname),
-        extensions,
       });
       const validation = validate(ast);
       if (validation) {

From 38c949eb10eb0fea6d5c240202672035c5e98365 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Mon, 17 Apr 2023 12:22:56 -0400
Subject: [PATCH 11/18] docs: normalize use of Token import

---
 lib/productions/interface.js | 2 +-
 lib/productions/mixin.js     | 4 +---
 lib/productions/operation.js | 6 ++----
 3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/lib/productions/interface.js b/lib/productions/interface.js
index f361e527..0f88e77c 100644
--- a/lib/productions/interface.js
+++ b/lib/productions/interface.js
@@ -34,7 +34,7 @@ function static_member(tokeniser) {
 export class Interface extends Container {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
-   * @param {Token} base
+   * @param {import("../tokeniser.js").Token} base
    * @param {object} [options]
    * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    * @param {import("../tokeniser.js").Token|null} [options.partial]
diff --git a/lib/productions/mixin.js b/lib/productions/mixin.js
index 5108efdb..19cce9f8 100644
--- a/lib/productions/mixin.js
+++ b/lib/productions/mixin.js
@@ -6,10 +6,8 @@ import { stringifier } from "./helpers.js";
 
 export class Mixin extends Container {
   /**
-   * @typedef {import("../tokeniser.js").Token} Token
-   *
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
-   * @param {Token} base
+   * @param {import("../tokeniser.js").Token} base
    * @param {object} [options]
    * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    * @param {import("../tokeniser.js").Token} [options.partial]
diff --git a/lib/productions/operation.js b/lib/productions/operation.js
index b92c10aa..380ada5e 100644
--- a/lib/productions/operation.js
+++ b/lib/productions/operation.js
@@ -9,12 +9,10 @@ import { validationError } from "../error.js";
 
 export class Operation extends Base {
   /**
-   * @typedef {import("../tokeniser.js").Token} Token
-   *
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {object} [options]
-   * @param {Token} [options.special]
-   * @param {Token} [options.regular]
+   * @param {import("../tokeniser.js").Token} [options.special]
+   * @param {import("../tokeniser.js").Token} [options.regular]
    */
   static parse(tokeniser, { special, regular } = {}) {
     const tokens = { special };

From 12e19d06c2a55e88fa704d7e77a411f42b4965b1 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Mon, 17 Apr 2023 12:23:11 -0400
Subject: [PATCH 12/18] test: fix import of expect function

---
 test/custom-production.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/custom-production.js b/test/custom-production.js
index 5ada1068..7c11dce7 100644
--- a/test/custom-production.js
+++ b/test/custom-production.js
@@ -1,4 +1,4 @@
-import expect from "expect";
+import { expect } from "expect";
 
 import { parse, write } from "webidl2";
 import { Base } from "../lib/productions/base.js";

From 364de96a049203a61e2db78318c40119b2335085 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Mon, 17 Apr 2023 12:26:37 -0400
Subject: [PATCH 13/18] docs: mark args as any

This is also due to https://github.com/microsoft/TypeScript/issues/4628
which prevents changing the signature of static methods on inherited
classes.
---
 lib/productions/container.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/productions/container.js b/lib/productions/container.js
index ed628aae..ef078af7 100644
--- a/lib/productions/container.js
+++ b/lib/productions/container.js
@@ -33,9 +33,7 @@ export class Container extends Base {
   /**
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {*} instance TODO: This should be {T extends Container}, but see https://github.com/microsoft/TypeScript/issues/4628
-   * @param {object} args
-   * @param {boolean} args.inheritable
-   * @param {AllowedMember[]} args.allowedMembers
+   * @param {*} args
    */
   static parse(tokeniser, instance, { inheritable, allowedMembers }) {
     const { tokens, type } = instance;

From 59b4172902a4c831d023ac94b4f942dc6d1fa059 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Mon, 17 Apr 2023 12:27:12 -0400
Subject: [PATCH 14/18] docs: fix path to container.js

---
 lib/webidl2.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index aa532426..b02d659a 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -13,7 +13,7 @@ import { autoParenter } from "./productions/helpers.js";
 import { Eof } from "./productions/token.js";
 
 /** @typedef {'callbackInterface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
-/** @typedef {Object.<'extMembers', import("./container.js").AllowedMember[] >} Extension */
+/** @typedef {Object.<'extMembers', import("./productions/container.js").AllowedMember[] >} Extension */
 /** @typedef {Object.<[ExtendableInterfaces], Extension>} Extensions */
 
 /**

From 38ffe973444610d4475d88a667cc26ae3ba111e0 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Wed, 19 Apr 2023 10:48:16 -0400
Subject: [PATCH 15/18] refactor: remove unnecessary spread operator

---
 lib/webidl2.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index b02d659a..6c3bc08d 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -102,7 +102,7 @@ function parseByTokens(tokeniser, options) {
       Enum.parse(tokeniser) ||
       Typedef.parse(tokeniser) ||
       Includes.parse(tokeniser) ||
-      Namespace.parse(tokeniser, { ...options?.extensions?.namespace })
+      Namespace.parse(tokeniser, options?.extensions?.namespace)
     );
   }
 

From 688adf2d1838cf62c4e53a340197ba4bcff55cb1 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Tue, 20 Jun 2023 12:01:54 -0400
Subject: [PATCH 16/18] docs: fix jsdoc types

Co-authored-by: Kagami Sascha Rosylight <saschanaz@outlook.com>
---
 lib/webidl2.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/webidl2.js b/lib/webidl2.js
index 6c3bc08d..26a020ad 100644
--- a/lib/webidl2.js
+++ b/lib/webidl2.js
@@ -13,8 +13,8 @@ import { autoParenter } from "./productions/helpers.js";
 import { Eof } from "./productions/token.js";
 
 /** @typedef {'callbackInterface'|'dictionary'|'interface'|'mixin'|'namespace'} ExtendableInterfaces */
-/** @typedef {Object.<'extMembers', import("./productions/container.js").AllowedMember[] >} Extension */
-/** @typedef {Object.<[ExtendableInterfaces], Extension>} Extensions */
+/** @typedef {{ extMembers?: import("./productions/container.js").AllowedMember[]}} Extension */
+/** @typedef {Partial<Record<ExtendableInterfaces, Extension>>} Extensions */
 
 /**
  * Parser options.

From bc54d0eadef41c732fd5c232ffbb1f79f0f3bcf5 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Tue, 20 Jun 2023 12:02:01 -0400
Subject: [PATCH 17/18] docs: fix jsdoc types

Co-authored-by: Kagami Sascha Rosylight <saschanaz@outlook.com>
---
 lib/productions/container.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/productions/container.js b/lib/productions/container.js
index ef078af7..8f1f22d5 100644
--- a/lib/productions/container.js
+++ b/lib/productions/container.js
@@ -18,7 +18,7 @@ function inheritance(tokeniser) {
 
 /**
  * Parser callback.
- * @callback parserCallback
+ * @callback ParserCallback
  * @param {import("../tokeniser.js").Tokeniser} tokeniser
  * @param {...*} args
  */
@@ -26,7 +26,7 @@ function inheritance(tokeniser) {
 /**
  * A parser callback and optional option object.
  * @typedef AllowedMember
- * @type {[parserCallback, object?]}
+ * @type {[ParserCallback, object?]}
  */
 
 export class Container extends Base {

From bdf5ee4d7e7741a0a8705f496175aad1d6cf9721 Mon Sep 17 00:00:00 2001
From: pyoor <pyoor@users.noreply.github.com>
Date: Wed, 21 Jun 2023 09:39:21 -0400
Subject: [PATCH 18/18] fix: remove iheritance attribute from CallbackInterface

---
 lib/productions/callback-interface.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/productions/callback-interface.js b/lib/productions/callback-interface.js
index 293b4a83..a22b0098 100644
--- a/lib/productions/callback-interface.js
+++ b/lib/productions/callback-interface.js
@@ -7,10 +7,9 @@ export class CallbackInterface extends Container {
    * @param {import("../tokeniser.js").Tokeniser} tokeniser
    * @param {*} callback
    * @param {object} [options]
-   * @param {boolean} [options.inheritable]
    * @param {import("./container.js").AllowedMember[]} [options.extMembers]
    */
-  static parse(tokeniser, callback, { inheritable, extMembers = [] } = {}) {
+  static parse(tokeniser, callback, { extMembers = [] } = {}) {
     const tokens = { callback };
     tokens.base = tokeniser.consume("interface");
     if (!tokens.base) {
@@ -20,7 +19,6 @@ export class CallbackInterface extends Container {
       tokeniser,
       new CallbackInterface({ source: tokeniser.source, tokens }),
       {
-        inheritable: !!inheritable,
         allowedMembers: [
           ...extMembers,
           [Constant.parse],