92 lines
1.8 KiB
JavaScript
92 lines
1.8 KiB
JavaScript
/**
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* The MIT License (MIT)
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* Copyright (c) 2017-present Dmitry Soshnikov <[email protected]>
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*/
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'use strict';
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/**
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* A regexp-tree plugin to replace single char group disjunction to char group
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*
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* a|b|c -> [abc]
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* [12]|3|4 -> [1234]
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* (a|b|c) -> ([abc])
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* (?:a|b|c) -> [abc]
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*/
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module.exports = {
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Disjunction: function Disjunction(path) {
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var node = path.node,
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parent = path.parent;
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if (!handlers[parent.type]) {
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return;
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}
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var charset = new Map();
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if (!shouldProcess(node, charset) || !charset.size) {
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return;
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}
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var characterClass = {
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type: 'CharacterClass',
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expressions: Array.from(charset.keys()).sort().map(function (key) {
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return charset.get(key);
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})
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};
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handlers[parent.type](path.getParent(), characterClass);
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}
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};
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var handlers = {
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RegExp: function RegExp(path, characterClass) {
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var node = path.node;
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node.body = characterClass;
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},
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Group: function Group(path, characterClass) {
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var node = path.node;
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if (node.capturing) {
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node.expression = characterClass;
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} else {
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path.replace(characterClass);
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}
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}
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};
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function shouldProcess(expression, charset) {
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if (!expression) {
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// Abort on empty disjunction part
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return false;
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}
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var type = expression.type;
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if (type === 'Disjunction') {
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var left = expression.left,
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right = expression.right;
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return shouldProcess(left, charset) && shouldProcess(right, charset);
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} else if (type === 'Char') {
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var value = expression.value;
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charset.set(value, expression);
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return true;
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} else if (type === 'CharacterClass' && !expression.negative) {
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return expression.expressions.every(function (expression) {
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return shouldProcess(expression, charset);
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});
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}
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return false;
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} |