OptimistXL

http://github.com/nanobowers/optimist_xl

Documentation

• Wiki: http://github.com/nanobowers/optimist_xl/wiki
• Examples: http://github.com/nanobowers/optimist_xl/tree/master/examples
• Code quickstart: See OptimistXL.options and then OptimistXL::Parser#opt.

Description

OptimistXL is a commandline option parser for Ruby that just gets out of your way. One line of code per option is all you need to write. For that, you get a nice automatically-generated help page, robust option parsing, and sensible defaults for everything you don't specify.

This code is a feature-fork of Optimist: https://github.com/ManageIQ/optimist

See the Extended Features section below for the differences/enhancements

Features

• Simple usage.
• Sensible defaults. No tweaking necessary, much tweaking possible.
• Support for long options, short options, subcommands, and automatic type validation and conversion.
• Automatic help message generation, wrapped to current screen width.

Extended features unavailable in the original Optimist gem

Parser Settings

• Automatic suggestions whens incorrect options are given
  • disable with suggestions: false
  • see example below
• Inexact matching of long arguments
  • disable with exact_match: true
  • see example below
• Available prevention of short-arguments by default
  • enable with explicit_short_opts: true

Option Settings

Permitted

Permitted options allow specifying valid choices for an option using lists, ranges or regexp's

• permitted: to specify a allow lists, ranges or regexp filtering of options.
• permitted_response: can be added to provide more explicit output when incorrect choices are given.
• see example
• concept and code via @akhoury6

Alternate named options

Short options can now take be provided as an Array of list of alternate short-option characters.

• opt :cat, 'desc', short: ['c', 't']
• Previously short: only accepted a single character.

Long options can be given alternate names using alt:

• opt :length, 'desc', alt: ['size']
• Note that long: 'othername' still exists to override the named option and can be used in addition to the alt names.

See example

Stringflag option-type

It is useful to allow an option that can be set as a string, used with a default string or unset, especialy in the case of specifying a log-file. AFAICT this was not possible with the original Optimist.

Example:

For this option definition:

opt :log, "Specify optional logfile", :type => :stringflag, :default => "progname.log"

The programmer should use the value of log_given in conjunction with the value of log to determine whether to enable logging what what the filename should be.

$ ./examples/optional_string_arg_type.rb -h
Options:
  -l, --log=<s?>, --no-log    specify optional log-file path (Default: progname.log)
  -h, --help                  Show this message

# Note that when no options are given, :log_given is not set, but the default passes through.
$ ./examples/optional_string_arg_type.rb
{:log=>"progname.log", :help=>false}

$ ./examples/optional_string_arg_type.rb -l
{:log=>"progname.log", :help=>false, :log_given=>true}

# In this case no-log can be used to force a false value into :log
$ ./examples/optional_string_arg_type.rb --no-log
{:log=>false, :help=>false, :log_given=>true}

# Overriding the default case
$ ./examples/optional_string_arg_type.rb --log othername.log
{:log=>"othername.log", :help=>false, :log_given=>true}

Subcommands

"Native" subcommand support - similar to sub-commands in Git.

• See example
• Ideas borrowed from https://github.com/jwliechty/trollop-subcommands

Automatic suggestions

Suggestions are formed using the DidYouMean gem, which is part of Ruby 2.3+. It uses the JaroWinkler and Levenshtein distance to determine when unknown options are within a certain 'distance' of a known option keyword.

$ ./examples/didyoumean.rb -h
Options:
  -c, --cone       Ice cream cone
  -z, --zippy      It zips
  -a, --zapzy      It zapz
  -b, --big-bug    Madagascar cockroach
  -h, --help       Show this message

# Suggestions for a simple misspelling

$ ./examples/didyoumean.rb --bone
Error: unknown argument '--bone'.  Did you mean: [--cone] ?.
Try --help for help.

# Letter transposition
$ ./examples/didyoumean.rb --ocne
Error: unknown argument '--ocne'.  Did you mean: [--cone] ?.
Try --help for help.

# Accidental plural

$ ./examples/didyoumean.rb --cones
Error: unknown argument '--cones'.  Did you mean: [--cone] ?.
Try --help for help.

# Two close matches, provide two suggestions.

$ ./examples/didyoumean.rb --zipzy
Error: unknown argument '--zipzy'.  Did you mean: [--zippy, --zapzy] ?.
Try --help for help.

# Posix-style options with '-' instead of '_' are a common mistake

$ ./examples/didyoumean.rb --big_bug
Error: unknown argument '--big_bug'.  Did you mean: [--big-bug] ?.
Try --help for help.

# Eventually the input option is too far away from 
# anything we know about so just say we dont understand

$ ./examples/didyoumean.rb --bugblatter-beast
Error: unknown argument '--bugblatter-beast'.
Try --help for help.

Inexact Matching

Similar to Perl's Getopt::Long, partially specified long-options can be used as long as they would unambiguously match a single option.

$ ./examples/partialmatch.rb -h
Options:
  -a, --apple          An apple
  -p, --apple-sauce    Cooked apple puree
  -t, --atom           Smallest unit of ordinary matter
  -n, --anvil          Heavy metal
  -e, --anteater       Eats ants
  -h, --help           Show this message

# Exact match for 'apple'
$ ./examples/partialmatch.rb --apple
{:apple=>true, :apple_sauce=>false, :atom=>false, :anvil=>false, :anteater=>false, :help=>false, :apple_given=>true}

# Cannot inexact match with 'app', as it partially matches more than one known option
$ ./examples/partialmatch.rb --app
Error: ambiguous option '--app' matched keys (apple,apple-sauce).
Try --help for help.

# Inexact match for 'apple-sauce'
$ ./examples/partialmatch.rb --apple-s
{:apple=>false, :apple_sauce=>true, :atom=>false, :anvil=>false, :anteater=>false, :help=>false, :apple_sauce_given=>true}

# Shortest match for 'anvil'
$ ./examples/partialmatch.rb --anv
{:apple=>false, :apple_sauce=>false, :atom=>false, :anvil=>true, :anteater=>false, :help=>false, :anvil_given=>true}

# Cannot inexact match with 'an', as it partially matches more than one known option
$ ./examples/partialmatch.rb --an
Error: ambiguous option '--an' matched keys (anvil,anteater).
Try --help for help.

# Shortest match for 'atom'
$ ./examples/partialmatch.rb --at
{:apple=>false, :apple_sauce=>false, :atom=>true, :anvil=>false, :anteater=>false, :help=>false, :atom_given=>true}

Requirements

• A burning desire to write less code.
• Ruby 2.3+

Install

• gem install optimist_xl

Synopsis

require 'optimist_xl'
opts = OptimistXL::options do
  opt :monkey, "Use monkey mode"                    # flag --monkey, default false
  opt :name, "Monkey name", :type => :string        # string --name <s>, default nil
  opt :num_limbs, "Number of limbs", :default => 4  # integer --num-limbs <i>, default to 4
end

p opts # a hash: { :monkey=>false, :name=>nil, :num_limbs=>4, :help=>false }

License

Copyright © 2008-2014 William Morgan.

Copyright © 2014 Red Hat, Inc.

Copyright © 2019-2020 Ben Bowers

OptimistXL is released under the MIT License.