/* Tokenizer for JavaScript code */
var tokenizeJavaScript = (function () {
// Advance the stream until the given character (not preceded by a
// backslash) is encountered, or the end of the line is reached.
function nextUntilUnescaped(source, end) {
var escaped = false;
var next;
while (!source.endOfLine()) {
var next = source.next();
if (next == end && !escaped)
return false;
escaped = !escaped && next == "\\";
}
return escaped;
}
// A map of JavaScript's keywords. The a/b/c keyword distinction is
// very rough, but it gives the parser enough information to parse
// correct code correctly (we don't care that much how we parse
// incorrect code). The style information included in these objects
// is used by the highlighter to pick the correct CSS style for a
// token.
var keywords = function () {
function result(type, style) {
return {type: type, style: "js-" + style};
}
// keywords that take a parenthised expression, and then a
// statement (if)
var keywordA = result("keyword a", "keyword");
// keywords that take just a statement (else)
var keywordB = result("keyword b", "keyword");
// keywords that optionally take an expression, and form a
// statement (return)
var keywordC = result("keyword c", "keyword");
var operator = result("operator", "keyword");
var atom = result("atom", "atom");
return {
"if": keywordA, "while": keywordA, "with": keywordA,
"else": keywordB, "do": keywordB, "try": keywordB, "finally": keywordB,
"return": keywordC, "break": keywordC, "continue": keywordC, "new": keywordC, "delete": keywordC, "throw": keywordC,
"in": operator, "typeof": operator, "instanceof": operator,
"var": result("var", "keyword"), "function": result("function", "keyword"), "catch": result("catch", "keyword"),
"for": result("for", "keyword"), "switch": result("switch", "keyword"),
"case": result("case", "keyword"), "default": result("default", "keyword"),
"true": atom, "false": atom, "null": atom, "undefined": atom, "NaN": atom, "Infinity": atom
};
}();
// Some helper regexps
var isOperatorChar = /[+\-*&%=<>!?|]/;
var isHexDigit = /[0-9A-Fa-f]/;
var isWordChar = /[\w\$_]/;
// Wrapper around jsToken that helps maintain parser state (whether
// we are inside of a multi-line comment and whether the next token
// could be a regular expression).
function jsTokenState(inside, regexp) {
return function (source, setState) {
var newInside = inside;
var type = jsToken(inside, regexp, source, function (c) {
newInside = c;
});
var newRegexp = type.type == "operator" || type.type == "keyword c" || type.type.match(/^[\[{}\(,;:]$/);
if (newRegexp != regexp || newInside != inside)
setState(jsTokenState(newInside, newRegexp));
return type;
};
}
// The token reader, inteded to be used by the tokenizer from
// tokenize.js (through jsTokenState). Advances the source stream
// over a token, and returns an object containing the type and style
// of that token.
function jsToken(inside, regexp, source, setInside) {
function readHexNumber() {
source.next(); // skip the 'x'
source.nextWhileMatches(isHexDigit);
return {type: "number", style: "js-atom"};
}
function readNumber() {
source.nextWhileMatches(/[0-9]/);
if (source.equals(".")) {
source.next();
source.nextWhileMatches(/[0-9]/);
}
if (source.equals("e") || source.equals("E")) {
source.next();
if (source.equals("-"))
source.next();
source.nextWhileMatches(/[0-9]/);
}
return {type: "number", style: "js-atom"};
}
// Read a word, look it up in keywords. If not found, it is a
// variable, otherwise it is a keyword of the type found.
function readWord() {
source.nextWhileMatches(isWordChar);
var word = source.get();
var known = keywords.hasOwnProperty(word) && keywords.propertyIsEnumerable(word) && keywords[word];
return known ? {type: known.type, style: known.style, content: word} :
{type: "variable", style: "js-variable", content: word};
}
function readRegexp() {
nextUntilUnescaped(source, "/");
source.nextWhileMatches(/[gi]/);
return {type: "regexp", style: "js-string"};
}
// Mutli-line comments are tricky. We want to return the newlines
// embedded in them as regular newline tokens, and then continue
// returning a comment token for every line of the comment. So
// some state has to be saved (inside) to indicate whether we are
// inside a /* */ sequence.
function readMultilineComment(start) {
var newInside = "/*";
var maybeEnd = (start == "*");
while (true) {
if (source.endOfLine())
break;
var next = source.next();
if (next == "/" && maybeEnd) {
newInside = null;
break;
}
maybeEnd = (next == "*");
}
setInside(newInside);
return {type: "comment", style: "js-comment"};
}
function readOperator() {
source.nextWhileMatches(isOperatorChar);
return {type: "operator", style: "js-operator"};
}
function readString(quote) {
var endBackSlash = nextUntilUnescaped(source, quote);
setInside(endBackSlash ? quote : null);
return {type: "string", style: "js-string"};
}
// Fetch the next token. Dispatches on first character in the
// stream, or first two characters when the first is a slash.
if (inside == "\"" || inside == "'")
return readString(inside);
var ch = source.next();
if (inside == "/*")
return readMultilineComment(ch);
else if (ch == "\"" || ch == "'")
return readString(ch);
// with punctuation, the type of the token is the symbol itself
else if (/[\[\]{}\(\),;\:\.]/.test(ch))
return {type: ch, style: "js-punctuation"};
else if (ch == "0" && (source.equals("x") || source.equals("X")))
return readHexNumber();
else if (/[0-9]/.test(ch))
return readNumber();
else if (ch == "/") {
if (source.equals("*")) {
source.next();
return readMultilineComment(ch);
}
else if (source.equals("/")) {
nextUntilUnescaped(source, null);
return {type: "comment", style: "js-comment"};
}
else if (regexp)
return readRegexp();
else
return readOperator();
}
else if (isOperatorChar.test(ch))
return readOperator();
else
return readWord();
}
// The external interface to the tokenizer.
return function (source, startState) {
return tokenizer(source, startState || jsTokenState(false, true));
};
})();
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