Improve code quality and write tests

This commit is contained in:
Shivam Mathur
2019-09-20 08:11:20 +05:30
parent db44db4b97
commit 43178a7254
3597 changed files with 255478 additions and 785554 deletions

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/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
var NFA = require('./nfa');
var NFAState = require('./nfa-state');
var _require = require('../special-symbols'),
EPSILON = _require.EPSILON;
// -----------------------------------------------------------------------------
// Char NFA fragment: `c`
/**
* Char factory.
*
* Creates an NFA fragment for a single char.
*
* [in] --c--> [out]
*/
function char(c) {
var inState = new NFAState();
var outState = new NFAState({
accepting: true
});
return new NFA(inState.addTransition(c, outState), outState);
}
// -----------------------------------------------------------------------------
// Epsilon NFA fragment
/**
* Epsilon factory.
*
* Creates an NFA fragment for ε (recognizes an empty string).
*
* [in] --ε--> [out]
*/
function e() {
return char(EPSILON);
}
// -----------------------------------------------------------------------------
// Alteration NFA fragment: `abc`
/**
* Creates a connection between two NFA fragments on epsilon transition.
*
* [in-a] --a--> [out-a] --ε--> [in-b] --b--> [out-b]
*/
function altPair(first, second) {
first.out.accepting = false;
second.out.accepting = true;
first.out.addTransition(EPSILON, second.in);
return new NFA(first.in, second.out);
}
/**
* Alteration factory.
*
* Creates a alteration NFA for (at least) two NFA-fragments.
*/
function alt(first) {
for (var _len = arguments.length, fragments = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
fragments[_key - 1] = arguments[_key];
}
var _iteratorNormalCompletion = true;
var _didIteratorError = false;
var _iteratorError = undefined;
try {
for (var _iterator = fragments[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
var fragment = _step.value;
first = altPair(first, fragment);
}
} catch (err) {
_didIteratorError = true;
_iteratorError = err;
} finally {
try {
if (!_iteratorNormalCompletion && _iterator.return) {
_iterator.return();
}
} finally {
if (_didIteratorError) {
throw _iteratorError;
}
}
}
return first;
}
// -----------------------------------------------------------------------------
// Disjunction NFA fragment: `a|b`
/**
* Creates a disjunction choice between two fragments.
*/
function orPair(first, second) {
var inState = new NFAState();
var outState = new NFAState();
inState.addTransition(EPSILON, first.in);
inState.addTransition(EPSILON, second.in);
outState.accepting = true;
first.out.accepting = false;
second.out.accepting = false;
first.out.addTransition(EPSILON, outState);
second.out.addTransition(EPSILON, outState);
return new NFA(inState, outState);
}
/**
* Disjunction factory.
*
* Creates a disjunction NFA for (at least) two NFA-fragments.
*/
function or(first) {
for (var _len2 = arguments.length, fragments = Array(_len2 > 1 ? _len2 - 1 : 0), _key2 = 1; _key2 < _len2; _key2++) {
fragments[_key2 - 1] = arguments[_key2];
}
var _iteratorNormalCompletion2 = true;
var _didIteratorError2 = false;
var _iteratorError2 = undefined;
try {
for (var _iterator2 = fragments[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
var fragment = _step2.value;
first = orPair(first, fragment);
}
} catch (err) {
_didIteratorError2 = true;
_iteratorError2 = err;
} finally {
try {
if (!_iteratorNormalCompletion2 && _iterator2.return) {
_iterator2.return();
}
} finally {
if (_didIteratorError2) {
throw _iteratorError2;
}
}
}
return first;
}
// -----------------------------------------------------------------------------
// Kleene-closure
/**
* Kleene star/closure.
*
* a*
*/
function repExplicit(fragment) {
var inState = new NFAState();
var outState = new NFAState({
accepting: true
});
// 0 or more.
inState.addTransition(EPSILON, fragment.in);
inState.addTransition(EPSILON, outState);
fragment.out.accepting = false;
fragment.out.addTransition(EPSILON, outState);
outState.addTransition(EPSILON, fragment.in);
return new NFA(inState, outState);
}
/**
* Optimized Kleene-star: just adds ε-transitions from
* input to the output, and back.
*/
function rep(fragment) {
fragment.in.addTransition(EPSILON, fragment.out);
fragment.out.addTransition(EPSILON, fragment.in);
return fragment;
}
/**
* Optimized Plus: just adds ε-transitions from
* the output to the input.
*/
function plusRep(fragment) {
fragment.out.addTransition(EPSILON, fragment.in);
return fragment;
}
/**
* Optimized ? repetition: just adds ε-transitions from
* the input to the output.
*/
function questionRep(fragment) {
fragment.in.addTransition(EPSILON, fragment.out);
return fragment;
}
module.exports = {
alt: alt,
char: char,
e: e,
or: or,
rep: rep,
repExplicit: repExplicit,
plusRep: plusRep,
questionRep: questionRep
};

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

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/**
* 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;

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/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();
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 _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); } }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
var _require = require('../special-symbols'),
EPSILON = _require.EPSILON,
EPSILON_CLOSURE = _require.EPSILON_CLOSURE;
/**
* NFA fragment.
*
* NFA sub-fragments can be combined to a larger NFAs building
* the resulting machine. Combining the fragments is done by patching
* edges of the in- and out-states.
*
* 2-states implementation, `in`, and `out`. Eventually all transitions
* go to the same `out`, which can further be connected via ε-transition
* with other fragment.
*/
var NFA = function () {
function NFA(inState, outState) {
_classCallCheck(this, NFA);
this.in = inState;
this.out = outState;
}
/**
* Tries to recognize a string based on this NFA fragment.
*/
_createClass(NFA, [{
key: 'matches',
value: function matches(string) {
return this.in.matches(string);
}
/**
* Returns an alphabet for this NFA.
*/
}, {
key: 'getAlphabet',
value: function getAlphabet() {
if (!this._alphabet) {
this._alphabet = new Set();
var table = this.getTransitionTable();
for (var state in table) {
var transitions = table[state];
for (var symbol in transitions) {
if (symbol !== EPSILON_CLOSURE) {
this._alphabet.add(symbol);
}
}
}
}
return this._alphabet;
}
/**
* Returns set of accepting states.
*/
}, {
key: 'getAcceptingStates',
value: function getAcceptingStates() {
if (!this._acceptingStates) {
// States are determined during table construction.
this.getTransitionTable();
}
return this._acceptingStates;
}
/**
* Returns accepting state numbers.
*/
}, {
key: 'getAcceptingStateNumbers',
value: function getAcceptingStateNumbers() {
if (!this._acceptingStateNumbers) {
this._acceptingStateNumbers = new Set();
var _iteratorNormalCompletion = true;
var _didIteratorError = false;
var _iteratorError = undefined;
try {
for (var _iterator = this.getAcceptingStates()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
var acceptingState = _step.value;
this._acceptingStateNumbers.add(acceptingState.number);
}
} catch (err) {
_didIteratorError = true;
_iteratorError = err;
} finally {
try {
if (!_iteratorNormalCompletion && _iterator.return) {
_iterator.return();
}
} finally {
if (_didIteratorError) {
throw _iteratorError;
}
}
}
}
return this._acceptingStateNumbers;
}
/**
* Builds and returns transition table.
*/
}, {
key: 'getTransitionTable',
value: function getTransitionTable() {
var _this = this;
if (!this._transitionTable) {
this._transitionTable = {};
this._acceptingStates = new Set();
var visited = new Set();
var symbols = new Set();
var visitState = function visitState(state) {
if (visited.has(state)) {
return;
}
visited.add(state);
state.number = visited.size;
_this._transitionTable[state.number] = {};
if (state.accepting) {
_this._acceptingStates.add(state);
}
var transitions = state.getTransitions();
var _iteratorNormalCompletion2 = true;
var _didIteratorError2 = false;
var _iteratorError2 = undefined;
try {
for (var _iterator2 = transitions[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
var _ref = _step2.value;
var _ref2 = _slicedToArray(_ref, 2);
var symbol = _ref2[0];
var symbolTransitions = _ref2[1];
var combinedState = [];
symbols.add(symbol);
var _iteratorNormalCompletion3 = true;
var _didIteratorError3 = false;
var _iteratorError3 = undefined;
try {
for (var _iterator3 = symbolTransitions[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
var nextState = _step3.value;
visitState(nextState);
combinedState.push(nextState.number);
}
} catch (err) {
_didIteratorError3 = true;
_iteratorError3 = err;
} finally {
try {
if (!_iteratorNormalCompletion3 && _iterator3.return) {
_iterator3.return();
}
} finally {
if (_didIteratorError3) {
throw _iteratorError3;
}
}
}
_this._transitionTable[state.number][symbol] = combinedState;
}
} catch (err) {
_didIteratorError2 = true;
_iteratorError2 = err;
} finally {
try {
if (!_iteratorNormalCompletion2 && _iterator2.return) {
_iterator2.return();
}
} finally {
if (_didIteratorError2) {
throw _iteratorError2;
}
}
}
};
// Traverse the graph starting from the `in`.
visitState(this.in);
// Append epsilon-closure column.
visited.forEach(function (state) {
delete _this._transitionTable[state.number][EPSILON];
_this._transitionTable[state.number][EPSILON_CLOSURE] = [].concat(_toConsumableArray(state.getEpsilonClosure())).map(function (s) {
return s.number;
});
});
}
return this._transitionTable;
}
}]);
return NFA;
}();
module.exports = NFA;