Contents

require 'transproc/composite'

module Transproc
  # Transformation proc wrapper allowing composition of multiple procs into
  # a data-transformation pipeline.
  #
  # This is used by Transproc to wrap registered methods.
  #
  # @api private
  class Function
    # Wrapped proc or another composite function
    #
    # @return [Proc,Composed]
    #
    # @api private
    attr_reader :fn

    # Additional arguments that will be passed to the wrapped proc
    #
    # @return [Array]
    #
    # @api private
    attr_reader :args

    # @!attribute [r] name
    #
    # @return [<type] The name of the function
    #
    # @api public
    attr_reader :name

    # @api private
    def initialize(fn, options = {})
      @fn = fn
      @args = options.fetch(:args, [])
      @name = options.fetch(:name, fn)
    end

    # Call the wrapped proc
    #
    # @param [Object] value The input value
    #
    # @alias []
    #
    # @api public
    def call(*value)
      fn[*value, *args]
    rescue => e
      raise MalformedInputError.new(@name, value, e)
    end
    alias_method :[], :call

    # Compose this function with another function or a proc
    #
    # @param [Proc,Function]
    #
    # @return [Composite]
    #
    # @alias :>>
    #
    # @api public
    def compose(other)
      Composite.new(self, other)
    end
    alias_method :+, :compose
    alias_method :>>, :compose

    # Return a new fn with curried args
    #
    # @return [Function]
    #
    # @api private
    def with(*args)
      self.class.new(fn, name: name, args: args)
    end

    # @api public
    def ==(other)
      return false unless other.instance_of?(self.class)
      [fn, name, args] == [other.fn, other.name, other.args]
    end
    alias_method :eql?, :==

    # Return a simple AST representation of this function
    #
    # @return [Array]
    #
    # @api public
    def to_ast
      [name, args]
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
transproc-0.3.0	lib/transproc/function.rb