Created
January 25, 2011 14:29
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| /* | |
| Pascal scanner | |
| */ | |
| var Lexeme = function(name, type, nextLexemePos) { | |
| this.name = name; | |
| this.type = type; | |
| this.nextLexemePos = nextLexemePos; | |
| } | |
| var Scanner = (function() { | |
| var keywords = [ | |
| /^real/gi, | |
| /^char/gi, | |
| /^string/gi, | |
| /^const/gi, | |
| /^var/gi, | |
| /^integer/gi, | |
| /^array/gi, | |
| /^of/gi, | |
| /^begin/gi, | |
| /^for/gi, | |
| /^while/gi, | |
| /^repeat/gi, | |
| /^if/gi, | |
| /^then/gi, | |
| /^else/gi, | |
| /^do/gi, | |
| /^to/gi, | |
| /^end/gi, | |
| /^until/gi, | |
| /^record/gi, | |
| /^div/gi, | |
| /^and/gi, | |
| /^or/gi, | |
| /^not/gi | |
| ], | |
| numbers = [ | |
| /^\-?\d+/g, | |
| /^\-?\d+[.]\d*/g, | |
| /^\-?\d+[.]\d*E\-\d+/g | |
| ], | |
| separators = [ | |
| /^:=/g, | |
| /^\.\./g, | |
| /^[:,.;()]/g | |
| ], | |
| operations = [ | |
| /^>=/g, | |
| /^<=/g, | |
| /^<>/g, | |
| /^[+\-*\/><=]/g | |
| ], | |
| identifiers = [ | |
| /^[a-z]+[a-z0-9_]*/g | |
| ], | |
| position = 0, | |
| code = null, | |
| program = null; | |
| var updateCodeAndPosition = function(pos) { | |
| position += pos; | |
| code = program.slice(position); | |
| }; | |
| var escape = function() { | |
| var regexps = [ | |
| /^\{(.|\n)*\}/g, | |
| /^\/\/(.)*$/gm, | |
| /^\s{1,}/g | |
| ///^\n/g | |
| ]; | |
| while(!regexps.every(function(regexp) { | |
| regexp.lastIndex = 0; | |
| var doesMatch = regexp.exec(code) !== null; | |
| pos = regexp.lastIndex; | |
| updateCodeAndPosition(regexp.lastIndex); | |
| return !doesMatch; | |
| })); | |
| }; | |
| var match = function() { | |
| var LexemeType = function(name, regexps) { | |
| this.name = name; | |
| this.regexps = regexps; | |
| }; | |
| var precedence = [ | |
| new LexemeType('Keyword', keywords), | |
| new LexemeType('Number', numbers), | |
| new LexemeType('Separator', separators), | |
| new LexemeType('Operation', operations), | |
| new LexemeType('Identifier', identifiers) | |
| ]; | |
| var lexemeType = null, | |
| lexemeName = null, | |
| lexemeEndPos = 0; | |
| precedence.every(function(type) { | |
| lexemeType = type.name; | |
| return type.regexps.every(function(regexp) { | |
| regexp.lastIndex = 0; | |
| matches = regexp.exec(code); | |
| if (matches !== null) { | |
| lexemeName = matches[matches.length-1]; | |
| lexemeEndPos = regexp.lastIndex; | |
| } | |
| return matches === null; | |
| }); | |
| }); | |
| updateCodeAndPosition(lexemeEndPos); | |
| escape(); | |
| return new Lexeme(lexemeName, lexemeType, position); | |
| }; | |
| return { | |
| init: function(prog) { | |
| program = prog; | |
| }, | |
| next: function(pos) { | |
| position = 0; | |
| updateCodeAndPosition(pos); | |
| escape(); | |
| return match(); | |
| } | |
| }; | |
| })(); |
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