94 lines
2.2 KiB
JavaScript
94 lines
2.2 KiB
JavaScript
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/**
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* The MIT License (MIT)
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* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
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*/
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'use strict';
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function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }
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var parser = require('../../../parser');
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var _require = require('./builders'),
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alt = _require.alt,
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char = _require.char,
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or = _require.or,
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rep = _require.rep,
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plusRep = _require.plusRep,
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questionRep = _require.questionRep;
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/**
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* Helper `gen` function calls node type handler.
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*/
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function gen(node) {
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if (node && !generator[node.type]) {
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throw new Error(node.type + ' is not supported in NFA/DFA interpreter.');
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}
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return node ? generator[node.type](node) : '';
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}
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/**
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* AST handler.
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*/
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var generator = {
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RegExp: function RegExp(node) {
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if (node.flags !== '') {
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throw new Error('NFA/DFA: Flags are not supported yet.');
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}
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return gen(node.body);
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},
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Alternative: function Alternative(node) {
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var fragments = (node.expressions || []).map(gen);
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return alt.apply(undefined, _toConsumableArray(fragments));
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},
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Disjunction: function Disjunction(node) {
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return or(gen(node.left), gen(node.right));
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},
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Repetition: function Repetition(node) {
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switch (node.quantifier.kind) {
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case '*':
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return rep(gen(node.expression));
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case '+':
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return plusRep(gen(node.expression));
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case '?':
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return questionRep(gen(node.expression));
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default:
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throw new Error('Unknown repeatition: ' + node.quantifier.kind + '.');
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}
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},
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Char: function Char(node) {
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if (node.kind !== 'simple') {
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throw new Error('NFA/DFA: Only simple chars are supported yet.');
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}
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return char(node.value);
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},
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Group: function Group(node) {
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return gen(node.expression);
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}
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};
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module.exports = {
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/**
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* Builds an NFA from the passed regexp.
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*/
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build: function build(regexp) {
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var ast = regexp;
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if (regexp instanceof RegExp) {
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regexp = '' + regexp;
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}
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if (typeof regexp === 'string') {
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ast = parser.parse(regexp, {
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captureLocations: true
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});
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}
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return gen(ast);
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}
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};
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