var isDigit = require('../../tokenizer').isDigit; var TYPE = require('../../tokenizer').TYPE; var CHARCODE = require('../../tokenizer').CHARCODE; var NUMBER = TYPE.Number; var DELIM = TYPE.Delim; var SOLIDUS = CHARCODE.Solidus; var FULLSTOP = CHARCODE.FullStop; // Terms of should be a positive numbers (not zero or negative) // (see https://drafts.csswg.org/mediaqueries-3/#values) // However, -o-min-device-pixel-ratio takes fractional values as a ratio's term // and this is using by various sites. Therefore we relax checking on parse // to test a term is unsigned number without an exponent part. // Additional checking may be applied on lexer validation. function consumeNumber() { this.scanner.skipWS(); var value = this.consume(NUMBER); for (var i = 0; i < value.length; i++) { var code = value.charCodeAt(i); if (!isDigit(code) && code !== FULLSTOP) { this.error('Unsigned number is expected', this.scanner.tokenStart - value.length + i); } } if (Number(value) === 0) { this.error('Zero number is not allowed', this.scanner.tokenStart - value.length); } return value; } // S* '/' S* module.exports = { name: 'Ratio', structure: { left: String, right: String }, parse: function() { var start = this.scanner.tokenStart; var left = consumeNumber.call(this); var right; this.scanner.skipWS(); if (!this.scanner.isDelim(SOLIDUS)) { this.error('Solidus is expected'); } this.eat(DELIM); right = consumeNumber.call(this); return { type: 'Ratio', loc: this.getLocation(start, this.scanner.tokenStart), left: left, right: right }; }, generate: function(node) { this.chunk(node.left); this.chunk('/'); this.chunk(node.right); } };