hashmake

Description

Make hash-based object initialization easy!

The hash_make method checks hashed arguments against a set of specifications, then values are assigned to instance variables matching the arg keys.

Features

Type checking via Object#is_a?. The default type is Object, allowing anything. Can allow multiple types. Mark as required/not. Set to true, by default. Default value, for non-required args that aren’t given. For default values that are mutable, make the default value a Proc that can be called to generate the mutable value. Validation of values via a Proc.

Examples

require 'hashmake'

class MyClass
  include Hashmake::HashMakeable

  ARG_SPECS = {
    :x => arg_spec(:reqd => true, :type => Float, :validator => ->(a){ a.between?(0.0,1.0) }),
    :y => arg_spec(:reqd => false, :type => Float, :validator => ->(a){ a.between?(0.0,1.0) }, :default => 0.0),
    :z => arg_spec_array(:reqd => false, :type => String, :validator => ->(a){ a.size > 0 })
  }

  attr_reader :x, :y, :z

  def initialize hashed_args
    hash_make(ARG_SPECS, hashed_args)
  end
end

a = MyClass.new :x => 0.5 # a.x => 0.5, a.y => 0.0
a = MyClass.new :x => 0.5, :y => 0.2 # a.x => 0.5, a.y => 0.2
a = MyClass.new # raise ArgumentError because :x is reqd and not given
a = MyClass.new :y => 0.5 # raise ArgumentError because :x is reqd and not given

a = MyClass.new :x => 0.5, :z => ["abc", "efg"] # OK
a = MyClass.new :x => 0.5, :z => ["abc", ""] # raise ArgumentError, because validator requires str.size > 0

class MultitypeDemo
  include Hashmake::HashMakeable

  ARG_SPECS = {
    :str_or_class => arg_spec(:reqd => true, :type => [String, Class])
  }
end

MultitypeDemo.new(:str_or_class => "")  # OK
MultitypeDemo.new(:str_or_class => String)  # OK
MultitypeDemo.new(:str_or_class => 1)  # raise ArgumentError

Requirements

Install

$ gem install hashmake

Copyright

See LICENSE.txt for details.