optionalargument

Description

DSL for method-arguments checker

Features

Flexible and readable definitions
Strict parser for key combinations
Key compatible for Symbol<->String
Validate and coerce values
You can use parsed options as Struct

Usage

You can mix following features :)
Clean up DEFUALT_OPTIONS.merge(options) and annoying validations!

Parser for arguments

require 'optionalargument'

class Foo
  def func(options={})
    opts = OptionalArgument.parse options do
      opt :a, must: true
      opt :b
    end

    p opts.a
    p opts.b?
    p opts.b
  end
end

foo = Foo.new
foo.func a: 1           #=> opts.a => 1, opts.b? => false, opts.b => nil
foo.func a: 1, "b" => 2 #=> opts.a => 1, opts.b? => true, opts.b => 2
foo.func "b" => 2       #=> Error (`a` is must, but not passed)
foo.func a:1, c: 3      #=> Error (`c` is not defined)

Key combinations

OptArg = OptionalArgument.define {
  opt :a
  opt :b
  conflict :a, :b
  opt :c, requirements: [:b, :d]
  opt :d, aliases: [:d2, :d3]
  opt :e, deprecateds: [:e2, :e3]
}

OptArg.parse(a: 1, b: 1) #=> Error: conflict conbination thrown: a, b'
OptArg.parse(c: 1)       #=> Error: `c` requires  `b` and `d`
OptArg.parse(d2: 1).d3   #=> 1
OptArg.parse(e2: 1).e3   #=> 1 with warning "`e2` is deprecated, use `e`"

Validate and coerce value

OptArg = OptionalArgument.define {
  opt :x, condition: 3..5
  opt :y, condition: AND(Float, 3..5)
  opt :z, adjuster: ->arg{Float arg}
}

OptArg.parse x: 5       #=> pass : 5 is sufficient for 3..5
OptArg.parse x: 6       #=> Error: 6 is deficient for 3..5
OptArg.parse y: 5       #=> Error: 5 is deficient for Float
OptArg.parse y: 5.0     #=> pass : 5.0 is sufficient for 3..5 and Float
OptArg.parse(z: '1').z  #=> 1.0  : casted under adjuster

Handle default values

OptArg = OptionalArgument.define {
  opt :a
  opt :b, default: 'This is a default value'
}

OptArg.parse(a: 1).b  #=> 'This is a default value'

Switch error

OptArg = OptionalArgument.define {
  opt :a
}

OptArg.parse({b: 1}, exception: ArgumentError) #=> ArgumentError
OptArg.parse({b: 1}, exception: KeyError)      #=> KeyError

This library helps you the building checkers for arguments. But normally behaves so relax. Because Builtin features are designed by relax parsing for unknown options.

OptArg = OptionalArgument.define {
  opt :known, must: true
}

opts = OptArg.parse(
         {known: 1, unknown: 2},
         defined_only: false)    #=> pass

Requirements

Ruby - 2.1 or later

Install

gem install optionalargument

Link

License

The MIT X11 License
Copyright (c) 2012 Kenichi Kamiya
See MIT-LICENSE for further details.