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lexer.js
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lexer.js
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/*!
* Jade - Lexer
* Copyright(c) 2010 TJ Holowaychuk <tj@vision-media.ca>
* MIT Licensed
*/
/**
* Initialize `Lexer` with the given `str`.
*
* @param {String} str
* @api private
*/
var Lexer = module.exports = function Lexer(str) {
this.input = str.replace(/\r\n|\r/g, '\n').replace(/\t/g, ' ');
this.deferredTokens = [];
this.lastIndents = 0;
this.lineno = 1;
this.stash = [];
};
/**
* Lexer prototype.
*/
Lexer.prototype = {
/**
* Construct a token with the given `type` and `val`.
*
* @param {String} type
* @param {String} val
* @return {Object}
* @api private
*/
tok: function(type, val){
return {
type: type,
line: this.lineno,
val: val
}
},
/**
* Consume the given `len` of input.
*
* @param {Number} len
* @api private
*/
consume: function(len){
this.input = this.input.substr(len);
},
/**
* Scan for `type` with the given `regexp`.
*
* @param {String} type
* @param {RegExp} regexp
* @return {Object}
* @api private
*/
scan: function(regexp, type){
var captures;
if (captures = regexp.exec(this.input)) {
this.consume(captures[0].length);
return this.tok(type, captures[1]);
}
},
/**
* Defer the given `tok`.
*
* @param {Object} tok
* @api private
*/
defer: function(tok){
this.deferredTokens.push(tok);
},
/**
* Lookahead `n` tokens.
*
* @param {Number} n
* @return {Object}
* @api private
*/
lookahead: function(n){
var fetch = n - this.stash.length;
while (fetch-- > 0) this.stash.push(this.next);
return this.stash[--n];
},
/**
* Stashed token.
*/
get stashed() {
return this.stash.length
&& this.stash.shift();
},
/**
* Deferred token.
*/
get deferred() {
return this.deferredTokens.length
&& this.deferredTokens.shift();
},
/**
* end-of-source.
*/
get eos() {
if (this.input.length) return;
return this.lastIndents-- > 0
? this.tok('outdent')
: this.tok('eos');
},
/**
* Comment.
*/
get comment() {
var captures;
if (captures = /^ *\/\/(-)?([^\n]+)/.exec(this.input)) {
this.consume(captures[0].length);
var tok = this.tok('comment', captures[2]);
tok.buffer = captures[1] !== '-';
return tok;
}
},
/**
* Tag.
*/
get tag() {
return this.scan(/^(\w[:-\w]*)/, 'tag');
},
/**
* Filter.
*/
get filter() {
return this.scan(/^:(\w+)/, 'filter');
},
/**
* Doctype.
*/
get doctype() {
return this.scan(/^!!! *(\w+)?/, 'doctype');
},
/**
* Id.
*/
get id() {
return this.scan(/^#([\w-]+)/, 'id');
},
/**
* Class.
*/
get className() {
return this.scan(/^\.([\w-]+)/, 'class');
},
/**
* Text.
*/
get text() {
return this.scan(/^(?:\| ?)?([^\n]+)/, 'text');
},
/**
* Each.
*/
get each() {
var captures;
if (captures = /^- *each *(\w+)(?: *, *(\w+))? * in *([^\n]+)/.exec(this.input)) {
this.consume(captures[0].length);
var tok = this.tok('each', captures[1]);
tok.key = captures[2] || 'index';
tok.code = captures[3];
return tok;
}
},
/**
* Code.
*/
get code() {
var captures;
if (captures = /^(!?=|-)([^\n]+)/.exec(this.input)) {
this.consume(captures[0].length);
var flags = captures[1];
captures[1] = captures[2];
var tok = this.tok('code', captures[1]);
tok.escape = flags[0] === '=';
tok.buffer = flags[0] === '=' || flags[1] === '=';
return tok;
}
},
/**
* Attributes.
*/
get attrs() {
var captures;
if (captures = /^\((.+)\)/.exec(this.input)) {
this.consume(captures[0].length);
var tok = this.tok('attrs', captures[1]),
attrs = tok.val.split(/ *, *(?=[\w-]+ *[:=]|[\w-]+ *$)/);
tok.attrs = {};
for (var i = 0, len = attrs.length; i < len; ++i) {
var pair = attrs[i];
// Support = and :
var colon = pair.indexOf(':'),
equal = pair.indexOf('=');
// Boolean
if (colon < 0 && equal < 0) {
var key = pair,
val = true;
} else {
// Split on first = or :
var split = equal >= 0
? equal
: colon;
if (colon >= 0 && colon < equal) split = colon;
var key = pair.substr(0, split),
val = pair.substr(++split, pair.length);
}
tok.attrs[key.trim().replace(/^['"]|['"]$/g, '')] = val;
}
return tok;
}
},
/**
* Indent.
*/
get indent() {
var captures;
if (captures = /^\n( *)/.exec(this.input)) {
++this.lineno;
this.consume(captures[0].length);
var tok = this.tok('indent', captures[1]),
indents = tok.val.length / 2;
if (this.input[0] === '\n') {
tok.type = 'newline';
return tok;
} else if (indents % 1 !== 0) {
throw new Error('Invalid indentation, got '
+ tok.val.length + ' space'
+ (tok.val.length > 1 ? 's' : '')
+ ', must be a multiple of two.');
} else if (indents === this.lastIndents) {
tok.type = 'newline';
} else if (indents > this.lastIndents + 1) {
throw new Error('Invalid indentation, got '
+ indents + ' expected '
+ (this.lastIndents + 1) + '.');
} else if (indents < this.lastIndents) {
var n = this.lastIndents - indents;
tok.type = 'outdent';
while (--n) {
this.defer(this.tok('outdent'));
}
}
this.lastIndents = indents;
return tok;
}
},
/**
* Return the next token object, or those
* previously stashed by lookahead.
*
* @return {Object}
* @api private
*/
get advance(){
return this.stashed
|| this.next;
},
/**
* Return the next token object.
*
* @return {Object}
* @api private
*/
get next() {
return this.deferred
|| this.eos
|| this.tag
|| this.filter
|| this.each
|| this.code
|| this.doctype
|| this.id
|| this.className
|| this.attrs
|| this.indent
|| this.comment
|| this.text;
}
};