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131 lines
3.2 KiB
131 lines
3.2 KiB
function noop(value) {
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return value;
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}
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function generateMultiplier(multiplier) {
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const { min, max, comma } = multiplier;
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if (min === 0 && max === 0) {
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return comma ? '#?' : '*';
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}
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if (min === 0 && max === 1) {
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return '?';
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}
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if (min === 1 && max === 0) {
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return comma ? '#' : '+';
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}
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if (min === 1 && max === 1) {
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return '';
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}
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return (
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(comma ? '#' : '') +
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(min === max
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? '{' + min + '}'
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: '{' + min + ',' + (max !== 0 ? max : '') + '}'
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)
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);
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}
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function generateTypeOpts(node) {
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switch (node.type) {
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case 'Range':
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return (
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' [' +
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(node.min === null ? '-∞' : node.min) +
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',' +
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(node.max === null ? '∞' : node.max) +
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']'
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);
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default:
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throw new Error('Unknown node type `' + node.type + '`');
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}
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}
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function generateSequence(node, decorate, forceBraces, compact) {
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const combinator = node.combinator === ' ' || compact ? node.combinator : ' ' + node.combinator + ' ';
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const result = node.terms
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.map(term => internalGenerate(term, decorate, forceBraces, compact))
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.join(combinator);
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if (node.explicit || forceBraces) {
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return (compact || result[0] === ',' ? '[' : '[ ') + result + (compact ? ']' : ' ]');
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}
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return result;
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}
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function internalGenerate(node, decorate, forceBraces, compact) {
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let result;
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switch (node.type) {
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case 'Group':
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result =
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generateSequence(node, decorate, forceBraces, compact) +
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(node.disallowEmpty ? '!' : '');
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break;
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case 'Multiplier':
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// return since node is a composition
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return (
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internalGenerate(node.term, decorate, forceBraces, compact) +
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decorate(generateMultiplier(node), node)
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);
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case 'Type':
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result = '<' + node.name + (node.opts ? decorate(generateTypeOpts(node.opts), node.opts) : '') + '>';
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break;
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case 'Property':
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result = '<\'' + node.name + '\'>';
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break;
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case 'Keyword':
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result = node.name;
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break;
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case 'AtKeyword':
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result = '@' + node.name;
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break;
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case 'Function':
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result = node.name + '(';
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break;
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case 'String':
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case 'Token':
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result = node.value;
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break;
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case 'Comma':
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result = ',';
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break;
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default:
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throw new Error('Unknown node type `' + node.type + '`');
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}
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return decorate(result, node);
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}
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export function generate(node, options) {
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let decorate = noop;
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let forceBraces = false;
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let compact = false;
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if (typeof options === 'function') {
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decorate = options;
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} else if (options) {
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forceBraces = Boolean(options.forceBraces);
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compact = Boolean(options.compact);
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if (typeof options.decorate === 'function') {
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decorate = options.decorate;
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}
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}
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return internalGenerate(node, decorate, forceBraces, compact);
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};
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