Class: Hashmake::ArgSpec

Inherits:
Object
  • Object
show all
Defined in:
lib/hashmake/arg_spec.rb

Overview

Provides a specification of how a hashed arg is to be processed by the hash_make method.

Author:

  • James Tunnell

Constant Summary collapse

DEFAULT_ARGS =

Defines default key/value pairs to use in initializing an instance. The :reqd key is set to true by default. The :validator key is set to a Proc that always returns true.

{
  :reqd => true,
  :validator => ->(a){true},
  :type => Object,
  :allow_nil => false
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hashed_args) ⇒ ArgSpec

A new instance of ArgSpec.

Parameters:

  • hashed_args (Hash) —

    Hash to use in initializing an instance. Optional keys are :type, :reqd, :validator, and :default. :type => the type of object expected to be paired

    with the key.

    :reqd => If true, the arg key must be in the hash

    passed to #initialize. If false, then a
default must be specified with :default
key. Set to true by default.

    :default => If reqd is false, this must be specified.

    This can be any object reference. If it
is a Proc, then the Proc will be called,
expecting it to produce the default.

    :validator => a Proc used to check the validity of

    whatever value is paired with an arg key.



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# File 'lib/hashmake/arg_spec.rb', line 41

def initialize hashed_args
  new_args = DEFAULT_ARGS.merge(hashed_args)
  
  @type = new_args[:type]
  if @type.is_a?(Enumerable)
    @type.each do |type|
      raise ArgumentError, "#{type} is not a Class" unless type.is_a?(Class)
    end
  else
    raise ArgumentError, "#{@type} is not a Class" unless @type.is_a?(Class)
  end
  
  @validator = new_args[:validator]
  @reqd = new_args[:reqd]
  
  unless @reqd
    msg = "if hashed arg is not required, a default value or value generator (proc) must be defined via :default key"
    raise ArgumentError, msg unless new_args.has_key?(:default)
    @default = new_args[:default]
  end
end

Instance Attribute Details

#default ⇒ Object (readonly)

Returns the value of attribute default.



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# File 'lib/hashmake/arg_spec.rb', line 23

def default
  @default
end

#reqd ⇒ Object (readonly)

Returns the value of attribute reqd.



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# File 'lib/hashmake/arg_spec.rb', line 23

def reqd
  @reqd
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/hashmake/arg_spec.rb', line 23

def type
  @type
end

#validator ⇒ Object (readonly)

Returns the value of attribute validator.



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# File 'lib/hashmake/arg_spec.rb', line 23

def validator
  @validator
end

Instance Method Details

#validate_value(val) ⇒ Object

Check the given value, and raise ArgumentError it is not valid.

Raises:

  • (ArgumentError) 


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# File 'lib/hashmake/arg_spec.rb', line 64

def validate_value val
  if @type.is_a?(Array)
    type_matched = false
    @type.each do |type|
      if val.is_a? type
        type_matched = true
      end
    end
    unless type_matched
      raise ArgumentError, "val #{val} is not one of #{@type}"
    end
  else
    raise ArgumentError, "val #{val} is not a #{@type}" unless val.is_a?(@type)
  end

  raise ArgumentError, "val #{val} is not valid" unless @validator.call(val)
end