72 lines
2.0 KiB
JavaScript
72 lines
2.0 KiB
JavaScript
'use strict';
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const types = require('../../tokenizer/types.cjs');
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const SOLIDUS = 0x002F; // U+002F SOLIDUS (/)
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// Media Queries Level 3 defines terms of <ratio> as a positive (not zero or negative)
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// integers (see https://drafts.csswg.org/mediaqueries-3/#values)
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// However, Media Queries Level 4 removes any definition of values
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// (see https://drafts.csswg.org/mediaqueries-4/#values) and refers to
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// CSS Values and Units for detail. In CSS Values and Units Level 4 a <ratio>
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// definition was added (see https://drafts.csswg.org/css-values-4/#ratios) which
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// defines ratio as "<number [0,∞]> [ / <number [0,∞]> ]?" and based on it
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// any constrains on terms were removed. Parser also doesn't test numbers
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// in any way to make possible for linting and fixing them by the tools using CSSTree.
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// An additional syntax examination may be applied by a lexer.
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function consumeTerm() {
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this.skipSC();
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switch (this.tokenType) {
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case types.Number:
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return this.Number();
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case types.Function:
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return this.Function(this.readSequence, this.scope.Value);
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default:
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this.error('Number of function is expected');
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}
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}
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const name = 'Ratio';
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const structure = {
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left: ['Number', 'Function'],
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right: ['Number', 'Function', null]
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};
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// <number [0,∞]> [ / <number [0,∞]> ]?
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function parse() {
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const start = this.tokenStart;
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const left = consumeTerm.call(this);
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let right = null;
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this.skipSC();
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if (this.isDelim(SOLIDUS)) {
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this.eatDelim(SOLIDUS);
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right = consumeTerm.call(this);
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}
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return {
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type: 'Ratio',
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loc: this.getLocation(start, this.tokenStart),
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left,
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right
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};
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}
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function generate(node) {
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this.node(node.left);
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this.token(types.Delim, '/');
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if (node.right) {
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this.node(node.right);
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} else {
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this.node(types.Number, 1);
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}
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}
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exports.generate = generate;
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exports.name = name;
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exports.parse = parse;
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exports.structure = structure;
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