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332 lines
9.4 KiB
332 lines
9.4 KiB
'use strict';
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const generate = require('regjsgen').generate;
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const parse = require('regjsparser').parse;
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const regenerate = require('regenerate');
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const unicodeMatchProperty = require('unicode-match-property-ecmascript');
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const unicodeMatchPropertyValue = require('unicode-match-property-value-ecmascript');
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const iuMappings = require('./data/iu-mappings.js');
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const ESCAPE_SETS = require('./data/character-class-escape-sets.js');
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// Prepare a Regenerate set containing all code points, used for negative
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// character classes (if any).
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const UNICODE_SET = regenerate().addRange(0x0, 0x10FFFF);
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// Without the `u` flag, the range stops at 0xFFFF.
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// https://mths.be/es6#sec-pattern-semantics
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const BMP_SET = regenerate().addRange(0x0, 0xFFFF);
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// Prepare a Regenerate set containing all code points that are supposed to be
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// matched by `/./u`. https://mths.be/es6#sec-atom
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const DOT_SET_UNICODE = UNICODE_SET.clone() // all Unicode code points
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.remove(
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// minus `LineTerminator`s (https://mths.be/es6#sec-line-terminators):
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0x000A, // Line Feed <LF>
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0x000D, // Carriage Return <CR>
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0x2028, // Line Separator <LS>
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0x2029 // Paragraph Separator <PS>
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);
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const getCharacterClassEscapeSet = (character, unicode, ignoreCase) => {
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if (unicode) {
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if (ignoreCase) {
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return ESCAPE_SETS.UNICODE_IGNORE_CASE.get(character);
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}
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return ESCAPE_SETS.UNICODE.get(character);
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}
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return ESCAPE_SETS.REGULAR.get(character);
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};
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const getUnicodeDotSet = (dotAll) => {
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return dotAll ? UNICODE_SET : DOT_SET_UNICODE;
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};
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const getUnicodePropertyValueSet = (property, value) => {
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const path = value ?
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`${ property }/${ value }` :
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`Binary_Property/${ property }`;
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try {
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return require(`regenerate-unicode-properties/${ path }.js`);
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} catch (exception) {
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throw new Error(
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`Failed to recognize value \`${ value }\` for property ` +
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`\`${ property }\`.`
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);
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}
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};
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const handleLoneUnicodePropertyNameOrValue = (value) => {
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// It could be a `General_Category` value or a binary property.
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// Note: `unicodeMatchPropertyValue` throws on invalid values.
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try {
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const property = 'General_Category';
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const category = unicodeMatchPropertyValue(property, value);
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return getUnicodePropertyValueSet(property, category);
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} catch (exception) {}
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// It’s not a `General_Category` value, so check if it’s a binary
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// property. Note: `unicodeMatchProperty` throws on invalid properties.
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const property = unicodeMatchProperty(value);
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return getUnicodePropertyValueSet(property);
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};
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const getUnicodePropertyEscapeSet = (value, isNegative) => {
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const parts = value.split('=');
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const firstPart = parts[0];
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let set;
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if (parts.length == 1) {
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set = handleLoneUnicodePropertyNameOrValue(firstPart);
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} else {
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// The pattern consists of two parts, i.e. `Property=Value`.
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const property = unicodeMatchProperty(firstPart);
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const value = unicodeMatchPropertyValue(property, parts[1]);
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set = getUnicodePropertyValueSet(property, value);
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}
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if (isNegative) {
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return UNICODE_SET.clone().remove(set);
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}
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return set.clone();
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};
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// Given a range of code points, add any case-folded code points in that range
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// to a set.
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regenerate.prototype.iuAddRange = function(min, max) {
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const $this = this;
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do {
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const folded = caseFold(min);
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if (folded) {
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$this.add(folded);
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}
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} while (++min <= max);
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return $this;
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};
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const update = (item, pattern) => {
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let tree = parse(pattern, config.useUnicodeFlag ? 'u' : '');
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switch (tree.type) {
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case 'characterClass':
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case 'group':
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case 'value':
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// No wrapping needed.
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break;
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default:
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// Wrap the pattern in a non-capturing group.
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tree = wrap(tree, pattern);
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}
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Object.assign(item, tree);
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};
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const wrap = (tree, pattern) => {
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// Wrap the pattern in a non-capturing group.
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return {
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'type': 'group',
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'behavior': 'ignore',
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'body': [tree],
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'raw': `(?:${ pattern })`
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};
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};
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const caseFold = (codePoint) => {
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return iuMappings.get(codePoint) || false;
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};
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const processCharacterClass = (characterClassItem, regenerateOptions) => {
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let set = regenerate();
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for (const item of characterClassItem.body) {
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switch (item.type) {
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case 'value':
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set.add(item.codePoint);
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if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
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const folded = caseFold(item.codePoint);
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if (folded) {
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set.add(folded);
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}
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}
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break;
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case 'characterClassRange':
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const min = item.min.codePoint;
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const max = item.max.codePoint;
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set.addRange(min, max);
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if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
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set.iuAddRange(min, max);
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}
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break;
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case 'characterClassEscape':
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set.add(getCharacterClassEscapeSet(
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item.value,
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config.unicode,
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config.ignoreCase
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));
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break;
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case 'unicodePropertyEscape':
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set.add(getUnicodePropertyEscapeSet(item.value, item.negative));
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break;
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// The `default` clause is only here as a safeguard; it should never be
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// reached. Code coverage tools should ignore it.
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/* istanbul ignore next */
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default:
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throw new Error(`Unknown term type: ${ item.type }`);
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}
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}
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if (characterClassItem.negative) {
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set = (config.unicode ? UNICODE_SET : BMP_SET).clone().remove(set);
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}
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update(characterClassItem, set.toString(regenerateOptions));
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return characterClassItem;
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};
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const updateNamedReference = (item, index) => {
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delete item.name;
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item.matchIndex = index;
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};
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const assertNoUnmatchedReferences = (groups) => {
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const unmatchedReferencesNames = Object.keys(groups.unmatchedReferences);
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if (unmatchedReferencesNames.length > 0) {
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throw new Error(`Unknown group names: ${unmatchedReferencesNames}`);
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}
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};
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const processTerm = (item, regenerateOptions, groups) => {
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switch (item.type) {
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case 'dot':
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if (config.unicode) {
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update(
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item,
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getUnicodeDotSet(config.dotAll).toString(regenerateOptions)
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);
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} else if (config.dotAll) {
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// TODO: consider changing this at the regenerate level.
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update(item, '[\\s\\S]');
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}
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break;
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case 'characterClass':
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item = processCharacterClass(item, regenerateOptions);
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break;
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case 'unicodePropertyEscape':
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update(
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item,
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getUnicodePropertyEscapeSet(item.value, item.negative)
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.toString(regenerateOptions)
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);
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break;
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case 'characterClassEscape':
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update(
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item,
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getCharacterClassEscapeSet(
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item.value,
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config.unicode,
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config.ignoreCase
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).toString(regenerateOptions)
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);
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break;
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case 'group':
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if (item.behavior == 'normal') {
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groups.lastIndex++;
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}
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if (item.name) {
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const name = item.name.value;
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if (groups.names[name]) {
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throw new Error(
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`Multiple groups with the same name (${ name }) are not allowed.`
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);
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}
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const index = groups.lastIndex;
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delete item.name;
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groups.names[name] = index;
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if (groups.onNamedGroup) {
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groups.onNamedGroup.call(null, name, index);
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}
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if (groups.unmatchedReferences[name]) {
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groups.unmatchedReferences[name].forEach(reference => {
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updateNamedReference(reference, index);
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});
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delete groups.unmatchedReferences[name];
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}
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}
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/* falls through */
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case 'alternative':
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case 'disjunction':
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case 'quantifier':
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item.body = item.body.map(term => {
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return processTerm(term, regenerateOptions, groups);
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});
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break;
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case 'value':
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const codePoint = item.codePoint;
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const set = regenerate(codePoint);
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if (config.ignoreCase && config.unicode && !config.useUnicodeFlag) {
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const folded = caseFold(codePoint);
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if (folded) {
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set.add(folded);
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}
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}
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update(item, set.toString(regenerateOptions));
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break;
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case 'reference':
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if (item.name) {
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const name = item.name.value;
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const index = groups.names[name];
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if (index) {
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updateNamedReference(item, index);
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break;
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}
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if (!groups.unmatchedReferences[name]) {
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groups.unmatchedReferences[name] = [];
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}
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// Keep track of references used before the corresponding group.
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groups.unmatchedReferences[name].push(item);
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}
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break;
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case 'anchor':
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case 'empty':
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case 'group':
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// Nothing to do here.
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break;
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// The `default` clause is only here as a safeguard; it should never be
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// reached. Code coverage tools should ignore it.
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/* istanbul ignore next */
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default:
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throw new Error(`Unknown term type: ${ item.type }`);
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}
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return item;
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};
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const config = {
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'ignoreCase': false,
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'unicode': false,
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'dotAll': false,
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'useUnicodeFlag': false
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};
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const rewritePattern = (pattern, flags, options) => {
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const regjsparserFeatures = {
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'unicodePropertyEscape': options && options.unicodePropertyEscape,
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'namedGroups': options && options.namedGroup,
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'lookbehind': options && options.lookbehind
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};
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config.ignoreCase = flags && flags.includes('i');
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config.unicode = flags && flags.includes('u');
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const supportDotAllFlag = options && options.dotAllFlag;
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config.dotAll = supportDotAllFlag && flags && flags.includes('s');
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config.useUnicodeFlag = options && options.useUnicodeFlag;
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const regenerateOptions = {
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'hasUnicodeFlag': config.useUnicodeFlag,
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'bmpOnly': !config.unicode
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};
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const groups = {
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'onNamedGroup': options && options.onNamedGroup,
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'lastIndex': 0,
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'names': Object.create(null), // { [name]: index }
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'unmatchedReferences': Object.create(null) // { [name]: Array<reference> }
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};
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const tree = parse(pattern, flags, regjsparserFeatures);
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// Note: `processTerm` mutates `tree` and `groups`.
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processTerm(tree, regenerateOptions, groups);
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assertNoUnmatchedReferences(groups);
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return generate(tree);
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};
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module.exports = rewritePattern;
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