Regex To DFA

This package takes a regular expression and transforms it into a deterministic finite automata (DFA). One is able to add multiple regular expressions to the DFA with specified identifiers. The DFA is able to check whether it accepts input and is able to return the specified identifier corresponding to that input.

Installation

To install this module via the node package manager (npm) use the command:

npm install regex-to-dfa

Use examples

Loading DFA

Once the DFA is installed one can load it using:

var DFA = require('regex-to-dfa').DFA;

Creating DFA

To create a new DFA which accepts any input corresponding to the regular expressions foo+ and ba*r with identifiers A and B respectively:

var myDFA = new DFA(new RegExp(/foo+/), 'A');
myDFA.add(new RegExp(/ba*r/), 'B');

Accepting input

To check whether input is accepted one uses

var isAccepted = myDFA.accepts('foo');
console.log(isAccepted);
>>> true

isAccepted = myDFA.accepts('abc');
console.log(isAccepted);
>>> false

To check what label corresponds to the input one uses

var label = myDFA.acceptingID('bar');
console.log(label);
>>> B

label = myDFA.acceptingID('abc');
console.log(label);
>>> undefined

Supported expressions

1. All character classes, e.g. ., [\s\S], \w, \W, \d, \D, \s, \S
2. All character sets, e.g. [ABC], [^ABC], [A-Z]
3. All escaped characters, e.g. \n, \+, \uFFFF, \xFF, \000
4. All quantifiers and alternation, e.g. +, *, {1,3}, ?, |

Unsupported expressions - expected in future releases

1. Groups, e.g. (abc)