cl-fsm/lib/regularExp.js

Regular Expression && FSM

'use strict';

const Parser = require('./parser');
const DFA = require('./dfa');

const RegularExp = function(exp) {
    if (typeof exp === 'string') {
        const parser = new Parser();
        const tnfa = parser.parse(exp);
        const end = tnfa.end;
        const {
            dfa,
            stateMap
        } = tnfa.nfa.toDFA(tnfa.start);

        this.dfa = dfa;
        this.ends = {};

        for (const state in stateMap) {
            const stateSet = stateMap[state];
            if (stateSet[end] !== undefined) {
                this.ends[state] = 1;
            }
        }
    } else if (exp && typeof exp === 'object') {
        this.dfa = DFA.getDFA(exp.dfa);
        this.ends = exp.ends;
    }
};

RegularExp.prototype = {
    constructor: RegularExp,

    getStartState: function() {
        return 0;
    },

    toJSONObj: function() {
        return {
            dfa: this.dfa.toJSONObj(),
            ends: this.ends
        };
    },

    test: function(tar) {
        let curState = this.getStartState();

        for (let i = 0, n = tar.length; i < n; i++) {
            const targetState = this.dfa.transit(curState, tar[i]);

            if (targetState === -1) {
                return false;
            } else {
                curState = targetState;
            }
        }

        if (this.ends[curState] === undefined) { // not accept state
            return false;
        }

        return true;
    },

    transit: function(state, letter) {
        return this.dfa.transit(state, letter);
    },

    isEndState: function(state) {
        return this.ends[state] !== undefined;
    },

    isErrorState: function(state) {
        return state === -1;
    }
};

module.exports = RegularExp;