569 lines
14 KiB
JavaScript
569 lines
14 KiB
JavaScript
var Tokenizer = require('./tokenizer');
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var TAB = 9;
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var N = 10;
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var F = 12;
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var R = 13;
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var SPACE = 32;
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var EXCLAMATIONMARK = 33; // !
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var NUMBERSIGN = 35; // #
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var AMPERSAND = 38; // &
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var APOSTROPHE = 39; // '
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var LEFTPARENTHESIS = 40; // (
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var RIGHTPARENTHESIS = 41; // )
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var ASTERISK = 42; // *
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var PLUSSIGN = 43; // +
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var COMMA = 44; // ,
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var HYPERMINUS = 45; // -
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var LESSTHANSIGN = 60; // <
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var GREATERTHANSIGN = 62; // >
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var QUESTIONMARK = 63; // ?
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var COMMERCIALAT = 64; // @
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var LEFTSQUAREBRACKET = 91; // [
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var RIGHTSQUAREBRACKET = 93; // ]
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var LEFTCURLYBRACKET = 123; // {
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var VERTICALLINE = 124; // |
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var RIGHTCURLYBRACKET = 125; // }
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var INFINITY = 8734; // ∞
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var NAME_CHAR = createCharMap(function(ch) {
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return /[a-zA-Z0-9\-]/.test(ch);
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});
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var COMBINATOR_PRECEDENCE = {
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' ': 1,
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'&&': 2,
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'||': 3,
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'|': 4
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};
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function createCharMap(fn) {
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var array = typeof Uint32Array === 'function' ? new Uint32Array(128) : new Array(128);
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for (var i = 0; i < 128; i++) {
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array[i] = fn(String.fromCharCode(i)) ? 1 : 0;
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}
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return array;
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}
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function scanSpaces(tokenizer) {
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return tokenizer.substringToPos(
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tokenizer.findWsEnd(tokenizer.pos)
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);
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}
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function scanWord(tokenizer) {
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var end = tokenizer.pos;
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for (; end < tokenizer.str.length; end++) {
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var code = tokenizer.str.charCodeAt(end);
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if (code >= 128 || NAME_CHAR[code] === 0) {
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break;
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}
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}
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if (tokenizer.pos === end) {
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tokenizer.error('Expect a keyword');
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}
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return tokenizer.substringToPos(end);
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}
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function scanNumber(tokenizer) {
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var end = tokenizer.pos;
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for (; end < tokenizer.str.length; end++) {
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var code = tokenizer.str.charCodeAt(end);
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if (code < 48 || code > 57) {
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break;
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}
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}
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if (tokenizer.pos === end) {
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tokenizer.error('Expect a number');
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}
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return tokenizer.substringToPos(end);
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}
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function scanString(tokenizer) {
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var end = tokenizer.str.indexOf('\'', tokenizer.pos + 1);
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if (end === -1) {
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tokenizer.pos = tokenizer.str.length;
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tokenizer.error('Expect an apostrophe');
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}
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return tokenizer.substringToPos(end + 1);
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}
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function readMultiplierRange(tokenizer) {
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var min = null;
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var max = null;
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tokenizer.eat(LEFTCURLYBRACKET);
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min = scanNumber(tokenizer);
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if (tokenizer.charCode() === COMMA) {
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tokenizer.pos++;
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if (tokenizer.charCode() !== RIGHTCURLYBRACKET) {
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max = scanNumber(tokenizer);
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}
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} else {
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max = min;
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}
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tokenizer.eat(RIGHTCURLYBRACKET);
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return {
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min: Number(min),
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max: max ? Number(max) : 0
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};
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}
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function readMultiplier(tokenizer) {
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var range = null;
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var comma = false;
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switch (tokenizer.charCode()) {
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case ASTERISK:
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tokenizer.pos++;
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range = {
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min: 0,
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max: 0
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};
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break;
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case PLUSSIGN:
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tokenizer.pos++;
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range = {
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min: 1,
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max: 0
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};
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break;
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case QUESTIONMARK:
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tokenizer.pos++;
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range = {
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min: 0,
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max: 1
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};
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break;
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case NUMBERSIGN:
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tokenizer.pos++;
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comma = true;
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if (tokenizer.charCode() === LEFTCURLYBRACKET) {
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range = readMultiplierRange(tokenizer);
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} else {
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range = {
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min: 1,
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max: 0
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};
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}
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break;
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case LEFTCURLYBRACKET:
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range = readMultiplierRange(tokenizer);
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break;
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default:
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return null;
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}
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return {
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type: 'Multiplier',
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comma: comma,
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min: range.min,
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max: range.max,
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term: null
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};
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}
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function maybeMultiplied(tokenizer, node) {
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var multiplier = readMultiplier(tokenizer);
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if (multiplier !== null) {
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multiplier.term = node;
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return multiplier;
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}
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return node;
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}
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function maybeToken(tokenizer) {
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var ch = tokenizer.peek();
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if (ch === '') {
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return null;
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}
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return {
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type: 'Token',
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value: ch
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};
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}
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function readProperty(tokenizer) {
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var name;
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tokenizer.eat(LESSTHANSIGN);
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tokenizer.eat(APOSTROPHE);
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name = scanWord(tokenizer);
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tokenizer.eat(APOSTROPHE);
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tokenizer.eat(GREATERTHANSIGN);
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return maybeMultiplied(tokenizer, {
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type: 'Property',
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name: name
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});
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}
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// https://drafts.csswg.org/css-values-3/#numeric-ranges
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// 4.1. Range Restrictions and Range Definition Notation
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//
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// Range restrictions can be annotated in the numeric type notation using CSS bracketed
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// range notation—[min,max]—within the angle brackets, after the identifying keyword,
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// indicating a closed range between (and including) min and max.
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// For example, <integer [0, 10]> indicates an integer between 0 and 10, inclusive.
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function readTypeRange(tokenizer) {
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// use null for Infinity to make AST format JSON serializable/deserializable
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var min = null; // -Infinity
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var max = null; // Infinity
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var sign = 1;
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tokenizer.eat(LEFTSQUAREBRACKET);
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if (tokenizer.charCode() === HYPERMINUS) {
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tokenizer.peek();
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sign = -1;
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}
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if (sign == -1 && tokenizer.charCode() === INFINITY) {
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tokenizer.peek();
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} else {
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min = sign * Number(scanNumber(tokenizer));
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}
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scanSpaces(tokenizer);
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tokenizer.eat(COMMA);
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scanSpaces(tokenizer);
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if (tokenizer.charCode() === INFINITY) {
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tokenizer.peek();
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} else {
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sign = 1;
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if (tokenizer.charCode() === HYPERMINUS) {
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tokenizer.peek();
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sign = -1;
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}
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max = sign * Number(scanNumber(tokenizer));
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}
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tokenizer.eat(RIGHTSQUAREBRACKET);
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// If no range is indicated, either by using the bracketed range notation
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// or in the property description, then [−∞,∞] is assumed.
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if (min === null && max === null) {
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return null;
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}
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return {
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type: 'Range',
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min: min,
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max: max
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};
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}
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function readType(tokenizer) {
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var name;
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var opts = null;
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tokenizer.eat(LESSTHANSIGN);
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name = scanWord(tokenizer);
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if (tokenizer.charCode() === LEFTPARENTHESIS &&
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tokenizer.nextCharCode() === RIGHTPARENTHESIS) {
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tokenizer.pos += 2;
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name += '()';
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}
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if (tokenizer.charCodeAt(tokenizer.findWsEnd(tokenizer.pos)) === LEFTSQUAREBRACKET) {
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scanSpaces(tokenizer);
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opts = readTypeRange(tokenizer);
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}
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tokenizer.eat(GREATERTHANSIGN);
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return maybeMultiplied(tokenizer, {
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type: 'Type',
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name: name,
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opts: opts
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});
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}
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function readKeywordOrFunction(tokenizer) {
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var name;
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name = scanWord(tokenizer);
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if (tokenizer.charCode() === LEFTPARENTHESIS) {
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tokenizer.pos++;
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return {
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type: 'Function',
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name: name
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};
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}
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return maybeMultiplied(tokenizer, {
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type: 'Keyword',
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name: name
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});
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}
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function regroupTerms(terms, combinators) {
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function createGroup(terms, combinator) {
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return {
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type: 'Group',
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terms: terms,
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combinator: combinator,
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disallowEmpty: false,
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explicit: false
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};
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}
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combinators = Object.keys(combinators).sort(function(a, b) {
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return COMBINATOR_PRECEDENCE[a] - COMBINATOR_PRECEDENCE[b];
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});
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while (combinators.length > 0) {
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var combinator = combinators.shift();
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for (var i = 0, subgroupStart = 0; i < terms.length; i++) {
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var term = terms[i];
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if (term.type === 'Combinator') {
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if (term.value === combinator) {
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if (subgroupStart === -1) {
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subgroupStart = i - 1;
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}
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terms.splice(i, 1);
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i--;
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} else {
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if (subgroupStart !== -1 && i - subgroupStart > 1) {
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terms.splice(
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subgroupStart,
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i - subgroupStart,
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createGroup(terms.slice(subgroupStart, i), combinator)
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);
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i = subgroupStart + 1;
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}
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subgroupStart = -1;
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}
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}
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}
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if (subgroupStart !== -1 && combinators.length) {
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terms.splice(
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subgroupStart,
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i - subgroupStart,
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createGroup(terms.slice(subgroupStart, i), combinator)
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);
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}
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}
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return combinator;
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}
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function readImplicitGroup(tokenizer) {
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var terms = [];
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var combinators = {};
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var token;
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var prevToken = null;
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var prevTokenPos = tokenizer.pos;
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while (token = peek(tokenizer)) {
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if (token.type !== 'Spaces') {
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if (token.type === 'Combinator') {
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// check for combinator in group beginning and double combinator sequence
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if (prevToken === null || prevToken.type === 'Combinator') {
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tokenizer.pos = prevTokenPos;
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tokenizer.error('Unexpected combinator');
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}
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combinators[token.value] = true;
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} else if (prevToken !== null && prevToken.type !== 'Combinator') {
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combinators[' '] = true; // a b
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terms.push({
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type: 'Combinator',
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value: ' '
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});
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}
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terms.push(token);
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prevToken = token;
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prevTokenPos = tokenizer.pos;
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}
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}
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// check for combinator in group ending
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if (prevToken !== null && prevToken.type === 'Combinator') {
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tokenizer.pos -= prevTokenPos;
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tokenizer.error('Unexpected combinator');
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}
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return {
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type: 'Group',
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terms: terms,
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combinator: regroupTerms(terms, combinators) || ' ',
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disallowEmpty: false,
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explicit: false
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};
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}
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function readGroup(tokenizer) {
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var result;
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tokenizer.eat(LEFTSQUAREBRACKET);
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result = readImplicitGroup(tokenizer);
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tokenizer.eat(RIGHTSQUAREBRACKET);
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result.explicit = true;
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if (tokenizer.charCode() === EXCLAMATIONMARK) {
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tokenizer.pos++;
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result.disallowEmpty = true;
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}
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return result;
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}
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function peek(tokenizer) {
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var code = tokenizer.charCode();
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if (code < 128 && NAME_CHAR[code] === 1) {
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return readKeywordOrFunction(tokenizer);
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}
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switch (code) {
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case RIGHTSQUAREBRACKET:
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// don't eat, stop scan a group
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break;
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case LEFTSQUAREBRACKET:
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return maybeMultiplied(tokenizer, readGroup(tokenizer));
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case LESSTHANSIGN:
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return tokenizer.nextCharCode() === APOSTROPHE
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? readProperty(tokenizer)
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: readType(tokenizer);
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case VERTICALLINE:
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return {
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type: 'Combinator',
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value: tokenizer.substringToPos(
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tokenizer.nextCharCode() === VERTICALLINE
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? tokenizer.pos + 2
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: tokenizer.pos + 1
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)
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};
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case AMPERSAND:
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tokenizer.pos++;
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tokenizer.eat(AMPERSAND);
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return {
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type: 'Combinator',
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value: '&&'
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};
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case COMMA:
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tokenizer.pos++;
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return {
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type: 'Comma'
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};
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case APOSTROPHE:
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return maybeMultiplied(tokenizer, {
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type: 'String',
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value: scanString(tokenizer)
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});
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case SPACE:
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case TAB:
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case N:
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case R:
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case F:
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return {
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type: 'Spaces',
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value: scanSpaces(tokenizer)
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};
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case COMMERCIALAT:
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code = tokenizer.nextCharCode();
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if (code < 128 && NAME_CHAR[code] === 1) {
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tokenizer.pos++;
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return {
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type: 'AtKeyword',
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name: scanWord(tokenizer)
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};
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}
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return maybeToken(tokenizer);
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case ASTERISK:
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case PLUSSIGN:
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case QUESTIONMARK:
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case NUMBERSIGN:
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case EXCLAMATIONMARK:
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// prohibited tokens (used as a multiplier start)
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break;
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case LEFTCURLYBRACKET:
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// LEFTCURLYBRACKET is allowed since mdn/data uses it w/o quoting
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// check next char isn't a number, because it's likely a disjoined multiplier
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code = tokenizer.nextCharCode();
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if (code < 48 || code > 57) {
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return maybeToken(tokenizer);
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}
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break;
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default:
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return maybeToken(tokenizer);
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}
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}
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function parse(source) {
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var tokenizer = new Tokenizer(source);
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var result = readImplicitGroup(tokenizer);
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if (tokenizer.pos !== source.length) {
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tokenizer.error('Unexpected input');
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}
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// reduce redundant groups with single group term
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if (result.terms.length === 1 && result.terms[0].type === 'Group') {
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result = result.terms[0];
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}
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return result;
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}
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// warm up parse to elimitate code branches that never execute
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// fix soft deoptimizations (insufficient type feedback)
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parse('[a&&<b>#|<\'c\'>*||e() f{2} /,(% g#{1,2} h{2,})]!');
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module.exports = parse;
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