feed

        # Enumerator.feed

(from ruby core)
---
    e.feed obj   -> nil

---

Sets the value to be returned by the next yield inside `e`.

If the value is not set, the yield returns nil.

This value is cleared after being yielded.

    # Array#map passes the array's elements to "yield" and collects the
    # results of "yield" as an array.
    # Following example shows that "next" returns the passed elements and
    # values passed to "feed" are collected as an array which can be
    # obtained by StopIteration#result.
    e = [1,2,3].map
    p e.next           #=> 1
    e.feed "a"
    p e.next           #=> 2
    e.feed "b"
    p e.next           #=> 3
    e.feed "c"
    begin
      e.next
    rescue StopIteration
      p $!.result      #=> ["a", "b", "c"]
    end

    o = Object.new
    def o.each
      x = yield         # (2) blocks
      p x               # (5) => "foo"
      x = yield         # (6) blocks
      p x               # (8) => nil
      x = yield         # (9) blocks
      p x               # not reached w/o another e.next
    end

    e = o.to_enum
    e.next              # (1)
    e.feed "foo"        # (3)
    e.next              # (4)
    e.next              # (7)
                        # (10)