regextest

Regextest

Regextest generates sample string that matches with regular expression. Unlike similar tools, it recognizes anchors, charactor classes and other advanced notation of ruby regex. Target users are programmers or students for debugging/learning regular expression.

Installation

You can use sample application without installation. For using at your local machine, add this line to your application's Gemfile:

gem 'regextest'

And then execute:

$ bundle

Or install it yourself as:

$ gem install regextest

Usage

require "regextest"

/\d{5}/.sample                   #=> "62853"
5.times.map{/\w{5}/.sample}      #=> ["mCcA5", "1s3Ae", "9HYbe", "x3T0A", "TJHlQ"]
/(?<=pre)body(?=post)/.sample    #=> "prebodypost"
/(?=[a-z])\w{5}(?<=_\d)/.sample  #=> "nCc_0"

/(?<=pre)body(?=post)/.match_data        #=> #<MatchData "body">

palindrome = /\A(?<a>|.|(?:(?<b>.)\g<a>\k<b+0>))\z/
palindrome.sample                #=> "a]r\\CC\\r]a"
palindrome.match_data            #=> #<MatchData "z2#2z" a:"z2#2z" b:"2">

Parameters (environment variables)

• REGEXTEST_DEBUG
  • Specify "1" to print verbose debugging information
• REGEXTEST_MAX_RETRY
  • Retry count for generation. 5 retry by default.
• REGEXTEST_MAX_REPEAT
  • Maximum repeat of element when * or + specified. Default value is 32.
• REGEXTEST_MAX_RECURSION
  • Maximum nest of \g<..>. Default value is 32.
• REGEXTEST_UNICODE_CHAR_SET
  • Whole character set at unicode mode. Specify unicode char-set names joined with "|". Default value is 'ascii|katakana|hiragana'
• REGEXTEST_TIMEOUT
  • Specify timeout second for verifying generated string (by ruby regexp). Default value is 1 second. Note no timeout detected for generating string. It can be used for fuzzering.

Exceptions

• Regextest::RegextestError
  • Impossible to generate string. It is sub-class of standard exception RuntimeError.
• Regextest::RegextestFailedToGenerate
  • Failed to generate string. It is sub-class of standard exception RuntimeError. In many cases, caused by Regextest's restriction)
• RuntimeError
  • Bug of Regextest
• Regextest::RegextestTimeout
  • Timeout (default is 1 sec) detected while verification. It is sub-class of standard exception RuntimeError. For ignoring verification, you can use sample method with 'verification: false' option.

  require "regextest"
  /(1|11){100}$/.sample                       #=> raise Regextest::Common::RegextestTimeout: ...
  /(1|11){100}$/.sample(verification: false)  #=> '11111111...'

Development

Visit git repository for developing

Contributing

1. Fork it ( https://bitbucket.org/ikomamik/regextest/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Major Bugs/Restrictions

1. Insufficient support of unicode classes
2. Too slow to process regex contains "Han" class
3. Limited support of possesive repeat
4. Limited support of grapheme cluster (\R or \X)

See issues tracker for more detail.