BREAKING CHANGE: Remove Namespaces

Author: pdubroy

doc/api-reference.md

@@ -14,18 +14,6 @@ Instantiate the Grammar defined by `source`. If specified, `optNamespace` is the
 
 Create a new Namespace containing Grammar instances for all of the grammars defined in `source`. If `optNamespace` is specified, it will be the prototype of the new Namespace.
 
-## Namespace objects
-
-When instantiating a grammar that refers to another grammar -- e.g. `MyJava <: Java { keyword += "async" }` -- the supergrammar name ('Java') is resolved to a grammar by looking up the name in a Namespace. In Ohm/JS, Namespaces are a plain old JavaScript objects, and an object literal like `{Java: myJavaGrammar}` can be passed to any API that expects a Namespace. For convenience, Ohm also has the following methods for working with namespaces:
-
-<b><pre class="api">ohm.namespace(optProps?: object)</pre></b>
-
-Create a new namespace. If `optProps` is specified, all of its properties will be copied to the new namespace.
-
-<b><pre class="api">ohm.extendNamespace(namespace: object, optProps?: object)</pre></b>
-
-Create a new namespace which inherits from `namespace`. If `optProps` is specified, all of its properties will be copied to the new namespace.
-
 ## Grammar objects
 
 A Grammar instance `g` has the following methods:

packages/cli/src/commands/generateBundles/index.js

@@ -73,9 +73,9 @@ function generateRecipe(grammarPath, grammars, writer, isEsm) {
     "'use strict';const ohm=require('ohm-js');";
 
   // If it's a single-grammar source file, the default export is the grammar.
-  // Otherwise, the export is a (possibly empty) Namespace containing the grammars.
+  // Otherwise, the export is a (possibly empty) object containing the grammars.
   if (!isSingleGrammar) {
-    output += 'const result=ohm.createNamespace();';
+    output += 'const result={};';
   }
   for (const [name, grammar] of Object.entries(grammars)) {
     const {superGrammar} = grammar;

packages/ohm-js/index.d.ts

@@ -53,25 +53,6 @@ declare namespace ohm {
    */
   function grammars(source: string, namespace?: Namespace): Namespace;
 
-  /**
-   * grammarsFromScriptElements was removed in Ohm v16.0. See
-   * https://ohmjs.org/d/gfs for more info.
-   * @deprecated
-   */
-  function grammarsFromScriptElements(nodeList?: unknown, namespace?: Namespace): Namespace;
-
-  /**
-   * Create a new namespace. If props is specified, all of its properties
-   * will be copied to the new namespace.
-   */
-  function namespace(props?: Object): Namespace;
-
-  /**
-   * Create a new namespace which inherits from namespace. If props is
-   * specified, all of its properties will be copied to the new namespace.
-   */
-  function extendNamespace(namespace: Namespace, props?: Object): Namespace;
-
   /**
    * A Namespace is a dictionary of Grammars
    */

packages/ohm-js/scripts/data/index.d.ts.template

@@ -52,25 +52,6 @@ declare namespace ohm {
    */
   function grammars(source: string, namespace?: Namespace): Namespace;
 
-  /**
-   * grammarsFromScriptElements was removed in Ohm v16.0. See
-   * https://ohmjs.org/d/gfs for more info.
-   * @deprecated
-   */
-  function grammarsFromScriptElements(nodeList?: unknown, namespace?: Namespace): Namespace;
-
-  /**
-   * Create a new namespace. If props is specified, all of its properties
-   * will be copied to the new namespace.
-   */
-  function namespace(props?: Object): Namespace;
-
-  /**
-   * Create a new namespace which inherits from namespace. If props is
-   * specified, all of its properties will be copied to the new namespace.
-   */
-  function extendNamespace(namespace: Namespace, props?: Object): Namespace;
-
   /**
    * A Namespace is a dictionary of Grammars
    */

packages/ohm-js/src/Namespace.js

@@ -7,6 +7,14 @@ import * as pexprs from './pexprs.js';
 
 const superSplicePlaceholder = Object.create(pexprs.PExpr.prototype);
 
+function namespaceHas(ns, name) {
+  // Look for an enumerable property, anywhere in the prototype chain.
+  for (const prop in ns) {
+    if (prop === name) return true;
+  }
+  return false;
+}
+
 // Returns a Grammar instance (i.e., an object with a `match` method) for
 // `tree`, which is the concrete syntax tree of a user-written grammar.
 // The grammar will be assigned into `namespace` under the name of the grammar
@@ -26,12 +34,12 @@ export function buildGrammar(match, namespace, optOhmGrammarForTesting) {
     },
     Grammar(id, s, _open, rules, _close) {
       const grammarName = id.visit();
-      decl = builder.newGrammar(grammarName, namespace);
+      decl = builder.newGrammar(grammarName);
       s.child(0) && s.child(0).visit();
       rules.children.map(c => c.visit());
       const g = decl.build();
       g.source = this.source.trimmed();
-      if (grammarName in namespace) {
+      if (namespaceHas(namespace, grammarName)) {
         throw errors.duplicateGrammarDeclaration(g, namespace);
       }
       namespace[grammarName] = g;
@@ -43,7 +51,7 @@ export function buildGrammar(match, namespace, optOhmGrammarForTesting) {
       if (superGrammarName === 'null') {
         decl.withSuperGrammar(null);
       } else {
-        if (!namespace || !(superGrammarName in namespace)) {
+        if (!namespace || !namespaceHas(namespace, superGrammarName)) {
           throw errors.undeclaredGrammar(superGrammarName, namespace, n.source);
         }
         decl.withSuperGrammar(namespace[superGrammarName]);

packages/ohm-js/src/buildGrammar.js

@@ -1,5 +1,4 @@
 import {assert} from './common.js';
-import {Namespace} from './Namespace.js';
 import * as pexprs from './pexprs-main.js';
 
 // --------------------------------------------------------------------
@@ -50,10 +49,7 @@ export function grammarSyntaxError(matchFailure) {
 
 export function undeclaredGrammar(grammarName, namespace, interval) {
   const message = namespace ?
-    'Grammar ' +
-      grammarName +
-      ' is not declared in namespace ' +
-      Namespace.toString(namespace) :
+    `Grammar ${grammarName} is not declared in namespace '${namespace}'` :
     'Undeclared grammar ' + grammarName;
   return createError(message, interval);
 }

packages/ohm-js/src/errors.js

@@ -3,7 +3,6 @@ import {buildGrammar} from './buildGrammar.js';
 import * as common from './common.js';
 import * as errors from './errors.js';
 import {Grammar} from './Grammar.js';
-import {Namespace} from './Namespace.js';
 import * as pexprs from './pexprs.js';
 import * as util from './util.js';
 
@@ -44,7 +43,7 @@ export function grammar(source, optNamespace) {
 }
 
 export function grammars(source, optNamespace) {
-  const ns = Namespace.extend(Namespace.asNamespace(optNamespace));
+  const ns = Object.create(optNamespace || {});
   if (typeof source !== 'string') {
     // For convenience, detect Node.js Buffer objects and automatically call toString().
     if (isBuffer(source)) {
@@ -72,7 +71,6 @@ export function grammarsFromScriptElements(optNodeOrNodeList) {
 }
 
 export * from './main-kernel.js';
-export const {createNamespace} = Namespace;
 export {ohmGrammar};
 export {pexprs, util};
 export {version} from './version.js';

packages/ohm-js/src/main.js

@@ -11,7 +11,7 @@ import ohm from '../index.mjs';
 
 test('namespaces', t => {
   const ns = ohm.grammars('G { start = "foo" }');
-  t.truthy(ns.G.match('foo'), 'G exists in the namespace and works');
+  t.is(ns.G.match('foo').succeeded(), true, 'G exists in the namespace and works');
 
   const ns2 = ohm.grammars('ccc { foo = "foo" }', ns);
   t.truthy(ns2);
@@ -30,6 +30,31 @@ test('namespaces', t => {
   t.deepEqual(ns3.G, ns2.G, 'super grammar is the same');
 });
 
+test('plain JS objects as namespaces', t => {
+  const ns = ohm.grammars('toString { start = "!!!" }');
+  t.is(ns.toString.match('!!!').succeeded(), true);
+
+  t.truthy(ohm.grammar('G <: toString {}', ns));
+  t.throws(() => ohm.grammar('G <: toString {}', {}), {
+    message: /Grammar toString is not declared/,
+  });
+
+  const toString = ohm.grammar('toString {}');
+  t.truthy(ohm.grammar('G <: toString {}', {toString}));
+  t.truthy(ohm.grammar('G <: toString {}', Object.create({toString})));
+
+  const ns2 = {};
+  Object.defineProperty(ns2, 'G', {
+    value: ohm.grammar('G {}'),
+    enumerable: false,
+  });
+  t.throws(
+      () => ohm.grammar('G2 <: G {}', ns2),
+      {message: /Grammar G is not declared/},
+      'an own, non-enumerable property is ignored',
+  );
+});
+
 test('instantiating grammars from different types of objects', t => {
   let g = ohm.grammar(fs.readFileSync('test/arithmetic.ohm'));
   t.is(g.match('1+2').succeeded(), true, 'works with a Buffer from fs.readFileSync()');

packages/ohm-js/test/test-main.js

@@ -1368,21 +1368,13 @@ describe('bootstrap', test => {
   });
 
   test('it can produce a grammar that works', t => {
-    const g = buildGrammar(
-        ns.Ohm.match(ohmGrammarSource, 'Grammar'),
-        ohm.createNamespace(),
-        ns.Ohm,
-    );
+    const g = buildGrammar(ns.Ohm.match(ohmGrammarSource, 'Grammar'), {}, ns.Ohm);
     assertSucceeds(
         t,
         g.match(ohmGrammarSource, 'Grammar'),
         'Ohm grammar can recognize itself',
     );
-    const Arithmetic = buildGrammar(
-        g.match(arithmeticGrammarSource, 'Grammar'),
-        ohm.createNamespace(),
-        g,
-    );
+    const Arithmetic = buildGrammar(g.match(arithmeticGrammarSource, 'Grammar'), {}, g);
     const s = Arithmetic.createSemantics().addAttribute('v', {
       exp(expr) {
         return expr.v;
@@ -1428,16 +1420,8 @@ describe('bootstrap', test => {
   });
 
   test('full bootstrap!', t => {
-    const g = buildGrammar(
-        ns.Ohm.match(ohmGrammarSource, 'Grammar'),
-        ohm.createNamespace(),
-        ns.Ohm,
-    );
-    const gPrime = buildGrammar(
-        g.match(ohmGrammarSource, 'Grammar'),
-        ohm.createNamespace(),
-        g,
-    );
+    const g = buildGrammar(ns.Ohm.match(ohmGrammarSource, 'Grammar'), {}, ns.Ohm);
+    const gPrime = buildGrammar(g.match(ohmGrammarSource, 'Grammar'), {}, g);
     gPrime.namespaceName = g.namespaceName; // make their namespaceName properties the same
     compareGrammars(t, g, gPrime);
   });

packages/ohm-js/test/test-ohm-syntax.js

@@ -31,7 +31,7 @@ test('simple grammar recipes', t => {
 });
 
 test('grammar recipes with supergrammars', t => {
-  const ns = ohm.createNamespace();
+  const ns = {};
   ns.G = ohm.grammar('G { start = end }');
   ns.G2 = ohm.grammar('G2 <: G { start := "a" }', ns);
 

packages/ohm-js/test/test-recipes.js

@@ -1,7 +1,6 @@
 import * as assert from 'uvu/assert';
 
 const expectedExports = [
-  'createNamespace',
   'grammar',
   'grammarFromScriptElement',
   'grammars',