feat: init

node_modules/regexp-tree/dist/interpreter/finite-automaton/nfa/nfa-state.js

@@ -0,0 +1,220 @@
+/**
+ * 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;