Create an object that is an improvement over Proc (curried by default and better inspection for debug)

function.rb

class Function
  attr_reader :arity, :source_location

  def initialize(&block)
    unless block_given?
      message = "tried to create #{self.class.name} object without a block"
      raise(ArgumentError, message)
    end

    @arity = block.arity
    @source_location = block.source_location
    define_singleton_method(:__call__, &block)
    @block = method(:__call__).curry
  end

  def call(*args)
    result = @block.call(*args)
    if @arity != -1 && @arity > args.size
      new_source = caller[0][/[^:]+:[^:]+/].split(":")
      new_arity = @arity - args.size
      new(new_source, new_arity, &result)
    else
      result
    end
  end
  alias_method :[], :call
  alias_method :===, :call
  alias_method :yield, :call

  def to_proc
    @block
  end

  def inspect
    id = "0x%014x" % (object_id << 1)
    source = @source_location.join(":")
    %(#<#{self.class.name}:#{id} #{source}>)
  end

  protected

  attr_writer :arity, :source_location

  private

  def new(source, arity, &block)
    self.class.new(&block).tap do |other|
      other.arity = arity
      other.source_location = source
    end
  end
end

def function(&block)
  Function.new(&block)
end

add = function { |a,b| a + b }

add.(1, 2)
add.(1)
add.(1).(2)

sum = function { |*n| n.reduce(:+) }

sum.(1)
sum.(1, 2)