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keksAccountGUI/node_modulesOLD/regexp-tree/dist/interpreter/finite-automaton/nfa/nfa-state.js
2019-08-11 20:48:02 +02:00

220 lines
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7.4 KiB
JavaScript

/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }
function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
var State = require('../state');
var _require = require('../special-symbols'),
EPSILON = _require.EPSILON;
/**
* NFA state.
*
* Allows nondeterministic transitions to several states on the
* same symbol, and also epsilon-transitions.
*/
var NFAState = function (_State) {
_inherits(NFAState, _State);
function NFAState() {
_classCallCheck(this, NFAState);
return _possibleConstructorReturn(this, (NFAState.__proto__ || Object.getPrototypeOf(NFAState)).apply(this, arguments));
}
_createClass(NFAState, [{
key: 'matches',
/**
* Whether this state matches a string.
*
* We maintain set of visited epsilon-states to avoid infinite loops
* when an epsilon-transition goes eventually to itself.
*
* NOTE: this function is rather "educational", since we use DFA for strings
* matching. DFA is built on top of NFA, and uses fast transition table.
*/
value: function matches(string) {
var visited = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : new Set();
// An epsilon-state has been visited, stop to avoid infinite loop.
if (visited.has(this)) {
return false;
}
visited.add(this);
// No symbols left..
if (string.length === 0) {
// .. and we're in the accepting state.
if (this.accepting) {
return true;
}
// Check if we can reach any accepting state from
// on the epsilon transitions.
var _iteratorNormalCompletion = true;
var _didIteratorError = false;
var _iteratorError = undefined;
try {
for (var _iterator = this.getTransitionsOnSymbol(EPSILON)[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
var nextState = _step.value;
if (nextState.matches('', visited)) {
return true;
}
}
} catch (err) {
_didIteratorError = true;
_iteratorError = err;
} finally {
try {
if (!_iteratorNormalCompletion && _iterator.return) {
_iterator.return();
}
} finally {
if (_didIteratorError) {
throw _iteratorError;
}
}
}
return false;
}
// Else, we get some symbols.
var symbol = string[0];
var rest = string.slice(1);
var symbolTransitions = this.getTransitionsOnSymbol(symbol);
var _iteratorNormalCompletion2 = true;
var _didIteratorError2 = false;
var _iteratorError2 = undefined;
try {
for (var _iterator2 = symbolTransitions[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
var _nextState = _step2.value;
if (_nextState.matches(rest)) {
return true;
}
}
// If we couldn't match on symbol, check still epsilon-transitions
// without consuming the symbol (i.e. continue from `string`, not `rest`).
} catch (err) {
_didIteratorError2 = true;
_iteratorError2 = err;
} finally {
try {
if (!_iteratorNormalCompletion2 && _iterator2.return) {
_iterator2.return();
}
} finally {
if (_didIteratorError2) {
throw _iteratorError2;
}
}
}
var _iteratorNormalCompletion3 = true;
var _didIteratorError3 = false;
var _iteratorError3 = undefined;
try {
for (var _iterator3 = this.getTransitionsOnSymbol(EPSILON)[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
var _nextState2 = _step3.value;
if (_nextState2.matches(string, visited)) {
return true;
}
}
} catch (err) {
_didIteratorError3 = true;
_iteratorError3 = err;
} finally {
try {
if (!_iteratorNormalCompletion3 && _iterator3.return) {
_iterator3.return();
}
} finally {
if (_didIteratorError3) {
throw _iteratorError3;
}
}
}
return false;
}
/**
* Returns an ε-closure for this state:
* self + all states following ε-transitions.
*/
}, {
key: 'getEpsilonClosure',
value: function getEpsilonClosure() {
var _this2 = this;
if (!this._epsilonClosure) {
(function () {
var epsilonTransitions = _this2.getTransitionsOnSymbol(EPSILON);
var closure = _this2._epsilonClosure = new Set();
closure.add(_this2);
var _iteratorNormalCompletion4 = true;
var _didIteratorError4 = false;
var _iteratorError4 = undefined;
try {
for (var _iterator4 = epsilonTransitions[Symbol.iterator](), _step4; !(_iteratorNormalCompletion4 = (_step4 = _iterator4.next()).done); _iteratorNormalCompletion4 = true) {
var nextState = _step4.value;
if (!closure.has(nextState)) {
closure.add(nextState);
var nextClosure = nextState.getEpsilonClosure();
nextClosure.forEach(function (state) {
return closure.add(state);
});
}
}
} catch (err) {
_didIteratorError4 = true;
_iteratorError4 = err;
} finally {
try {
if (!_iteratorNormalCompletion4 && _iterator4.return) {
_iterator4.return();
}
} finally {
if (_didIteratorError4) {
throw _iteratorError4;
}
}
}
})();
}
return this._epsilonClosure;
}
}]);
return NFAState;
}(State);
module.exports = NFAState;