Module: Kernel

Defined in:
lib/api_hammer/ycomb.rb

Class Method Summary collapse

Class Method Details

.ycomb ⇒ Object

this is the Y-combinator, which allows anonymous recursive functions. for a simple example, to define a recursive function to return the length of an array:

length = ycomb do |len| proc{|list| list == [] ? 0 : 1 + len.call(list[1..-1]) } end

see https://secure.wikimedia.org/wikipedia/en/wiki/Fixed_point_combinator#Y_combinator and chapter 9 of the little schemer, available as the sample chapter at http://www.ccs.neu.edu/home/matthias/BTLS/



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# File 'lib/api_hammer/ycomb.rb', line 11

def ycomb
  proc { |f| f.call(f) }.call(proc { |f| yield proc{|*x| f.call(f).call(*x) } })
end