var regexp = require('regexp')
var res = regexp('[a-z]+')
assert.deepEqual(res, { type: 'match',
  offset: 0,
  text: '[a-z]+',
  body:
   [ { type: 'quantified',
       offset: 0,
       text: '[a-z]+',
       body:
        { type: 'charset',
          offset: 0,
          text: '[a-z]',
          invert: false,
          body:
           [ { type: 'range',
               offset: 1,
               text: 'a-z',
               start: 'a',
               end: 'z' } ] },
       quantifier:
        { type: 'quantifier',
          offset: 5,
          text: '+',
          min: 1,
          max: Infinity,
          greedy: true } } ] })