earley-cfg

An npm module containing an implementation of the a Context Free Grammar (CFG) using the Earley algorithm. This is my take on this NPM module, with changes to suit my needs.

Example

var earley = require('earley-cfg');
 
var grammar = new earley.Grammar('grammar.cfg');
var parser = new earley.Parser(grammar);
 
var sentence = new earley.Sentence.SentenceFromString('time/time<N> flies/fly<N>/fly<V> like/like<V>/like<P> an/a<D> arrow/arrow<N>');
 
var result = parser.parse(sentence);
 
if(result.valid === true){
    console.log('Valid');
    var trees = new earley.ParseTrees(result);
    console.log(trees.toString());
}
else{
    console.log('Invalid');
}

grammar.cfg

S -> NP VP | VP
NP -> D N | N | N NP
VP -> V | V NP | V PP | V NP PP
PP -> P NP

Download

Install using Node Package Manager (npm):

npm install earley-cfg