curry

        # Proc.curry

(from ruby core)
---
    prc.curry         -> a_proc
    prc.curry(arity)  -> a_proc

---

Returns a curried proc. If the optional *arity* argument is given, it
determines the number of arguments. A curried proc receives some
arguments. If a sufficient number of arguments are supplied, it passes
the supplied arguments to the original proc and returns the result.
Otherwise, returns another curried proc that takes the rest of
arguments.

    b = proc {|x, y, z| (x||0) + (y||0) + (z||0) }
    p b.curry[1][2][3]           #=> 6
    p b.curry[1, 2][3, 4]        #=> 6
    p b.curry(5)[1][2][3][4][5]  #=> 6
    p b.curry(5)[1, 2][3, 4][5]  #=> 6
    p b.curry(1)[1]              #=> 1

    b = proc {|x, y, z, *w| (x||0) + (y||0) + (z||0) + w.inject(0, &:+) }
    p b.curry[1][2][3]           #=> 6
    p b.curry[1, 2][3, 4]        #=> 10
    p b.curry(5)[1][2][3][4][5]  #=> 15
    p b.curry(5)[1, 2][3, 4][5]  #=> 15
    p b.curry(1)[1]              #=> 1

    b = lambda {|x, y, z| (x||0) + (y||0) + (z||0) }
    p b.curry[1][2][3]           #=> 6
    p b.curry[1, 2][3, 4]        #=> wrong number of arguments (given 4, expected 3)
    p b.curry(5)                 #=> wrong number of arguments (given 5, expected 3)
    p b.curry(1)                 #=> wrong number of arguments (given 1, expected 3)

    b = lambda {|x, y, z, *w| (x||0) + (y||0) + (z||0) + w.inject(0, &:+) }
    p b.curry[1][2][3]           #=> 6
    p b.curry[1, 2][3, 4]        #=> 10
    p b.curry(5)[1][2][3][4][5]  #=> 15
    p b.curry(5)[1, 2][3, 4][5]  #=> 15
    p b.curry(1)                 #=> wrong number of arguments (given 1, expected 3)

    b = proc { :foo }
    p b.curry[]                  #=> :foo