Add a parser for regexp-style character classes.

source/stake.js

@@ -45,6 +45,18 @@ Stake.extend({
 });
 
 Stake.extend({
+  CharClassParser: new JS.Class(Stake.Parser, {
+    initialize: function(charClass) {
+      this._charClass = charClass;
+      this._pattern = new RegExp('^' + charClass);
+    },
+
+    consume: function(input, offset) {
+      var match = input.match(this._pattern);
+      return match ? this._syntaxNode(String(match), offset) : null;
+    }
+  }),
+
   ChoiceParser: new JS.Class(Stake.Parser, {
     extend: {
       create: function() {

spec/runner.js

@@ -7,7 +7,8 @@ JS.Packages(function() { with(this) {
 }})
 
 require('JS.Test', 'Stake', function() {
-    require('Stake.ChoiceParserSpec',
+    require('Stake.CharClassParserSpec',
+            'Stake.ChoiceParserSpec',
             'Stake.MaybeParserSpec',
             'Stake.RepeatParserSpec',
             'Stake.SequenceParserSpec',

spec/stake/char_class_parser_spec.js

@@ -0,0 +1,78 @@
+Stake.CharClassParserSpec = JS.Test.describe(Stake.CharClassParser,
+function() { with(this) {
+  describe('positive', function() { with(this) {
+    before(function() { with(this) {
+      this.parser = Stake.Parser.fromSexp(
+                    ['char-class', '[a-z]'])
+    }})
+
+    it('parses characters within the class', function() { with(this) {
+      assertEqual( {textValue: 'a', offset: 0, elements: []}, parser.parse('a') )
+    }})
+
+    it('does not parse characters outside the class', function() { with(this) {
+      assertNull( parser.parse('7') )
+    }})
+
+    it('does not parse characters within the class appearing too late', function() { with(this) {
+      assertNull( parser.parse('7a') )
+    }})
+  }})
+
+  describe('negative', function() { with(this) {
+    before(function() { with(this) {
+      this.parser = Stake.Parser.fromSexp(
+                    ['char-class', '[^a-z]'])
+    }})
+
+    it('parses characters within the class', function() { with(this) {
+      assertEqual( {textValue: '7', offset: 0, elements: []}, parser.parse('7') )
+    }})
+
+    it('does not parse characters outside the class', function() { with(this) {
+      assertNull( parser.parse('a') )
+    }})
+
+    it('does not parse characters within the class appearing too late', function() { with(this) {
+      assertNull( parser.parse('a7') )
+    }})
+  }})
+
+  describe('with sequencing and repetion', function() { with(this) {
+    before(function() { with(this) {
+      this.parser = Stake.Parser.fromSexp(
+                    ['sequence',
+                      ['char-class', '[1-9]'],
+                      ['repeat', 0, ['char-class', '[0-9]']]])
+    }})
+
+    it('parses integers', function() { with(this) {
+      assertEqual( {
+          textValue: '3718',
+          offset: 0,
+          elements: [
+            {textValue: '3', offset: 0, elements: []},
+            {
+              textValue: '718',
+              offset: 1,
+              elements: [
+                {textValue: '7', offset: 1, elements: []},
+                {textValue: '1', offset: 2, elements: []},
+                {textValue: '8', offset: 3, elements: []}
+              ]
+            }
+          ]
+        },
+        parser.parse('3718') )
+    }})
+
+    it('does not parse floats', function() { with(this) {
+      assertNull( parser.parse('7.4') )
+    }})
+
+    it('does not parse octal', function() { with(this) {
+      assertNull( parser.parse('0644') )
+    }})
+  }})
+}})
+