Class: SyntaxSugar::NullObject

Inherits:
BasicObject
Defined in:
lib/syntax_sugar/null_object.rb

Constant Summary collapse

VALID_TARGET_METHOD_TYPES = 
[::String, ::Symbol]
VALID_METHOD_MATCHERS_TYPES = 
[::Regexp]

Instance Method Summary collapse

Constructor Details

#initialize(subject_object, regexp_pointers = {}) ⇒ NullObject

Returns a new instance of NullObject.



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# File 'lib/syntax_sugar/null_object.rb', line 6

def initialize(subject_object, regexp_pointers = {})

  @__object__ = subject_object

  unless regexp_pointers.is_a?(::Hash)
    ::Kernel.raise(::ArgumentError, 'method pointer collection should be instance of Hash or Array')
  end

  if regexp_pointers.find{|k,v| !VALID_METHOD_MATCHERS_TYPES.any?{|klass| k.is_a?(klass) } }
    ::Kernel.raise(::ArgumentError,'invalid pointer given in the method definitions, use regular expression')
  end

  if regexp_pointers.find{|k,v| !VALID_TARGET_METHOD_TYPES.any?{|klass| v.is_a?(klass) } }
    ::Kernel.raise(::ArgumentError,'invalid target method given in the method definitions, use string or symbol')
  end

  @regexp_pointers = regexp_pointers

end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_name, *args, &block) ⇒ Object 



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# File 'lib/syntax_sugar/null_object.rb', line 26

def method_missing(method_name, *args, &block)

  @regexp_pointers.each do |regexp, target_method|

    if method_name.to_s =~ regexp

      if regexp.source =~ /\(.*\)/
        method_extraction = method_name.to_s.scan(regexp)[0][0]
        args.unshift(method_extraction)
      end

      return @__object__.__send__(
          target_method,
          *args, &block
      )

    end

  end

  ::Kernel.raise(::NameError,"undefined local variable or method `#{method_name}' for #{@__object__.inspect}:SyntaxSugar::NullObject")

end