Class: MaybeChain::MaybeWrapper

Inherits:
Delegator
  • Object
show all
Defined in:
lib/maybe-chain.rb

Instance Method Summary collapse

Constructor Details

#initialize(obj, rescuables = []) ⇒ MaybeWrapper

Returns a new instance of MaybeWrapper.

Raises:

  • (ArgumentError) 


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# File 'lib/maybe-chain.rb', line 7

def initialize(obj, rescuables = [])
  raise ArgumentError unless (rescuables.is_a?(Class) && rescuables <= Exception) || rescuables.is_a?(Array)

  if rescuables.is_a?(Exception)
    @rescuables = [rescuables]
  else
    @rescuables = rescuables
  end

  @obj = obj.nil? ? Nothing.instance : obj
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

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



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# File 'lib/maybe-chain.rb', line 31

def method_missing(m, *args, &block)
  if nothing?
    self.__getobj__.__send__(m, @rescuables, &block)
  else
    MaybeWrapper.new(super, @rescuables)
  end
rescue *@rescuables
  build_nothing
end

Instance Method Details

#__getobj__ ⇒ Object 



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# File 'lib/maybe-chain.rb', line 19

def __getobj__
  @obj
end

#inspect ⇒ Object 



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# File 'lib/maybe-chain.rb', line 23

def inspect
  "<Maybe: #{@obj.inspect}>"
end

#just? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/maybe-chain.rb', line 45

def just?
  !nothing?
end

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



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# File 'lib/maybe-chain.rb', line 53

def lift(method_name, *args, &block)
  return build_nothing if nothing?
  return build_nothing if args.any?(&:nothing?)

  extracts = args.map {|arg| arg.is_a?(MaybeChain::MaybeWrapper) ? arg.value : arg}
  MaybeWrapper.new(value.__send__(method_name, *extracts, &block), @rescuables)
rescue *@rescuables
  build_nothing
end

#nothing? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/maybe-chain.rb', line 41

def nothing?
  @obj.is_a? Nothing
end

#to_s ⇒ Object 



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# File 'lib/maybe-chain.rb', line 27

def to_s
  @obj.to_s
end

#value ⇒ Object 



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# File 'lib/maybe-chain.rb', line 49

def value
  nothing? ? nil : @obj
end