GTProgramControl

Docs currently at: http://www.ai.mit.edu/~jrb/goo/manual/goomanual_8.html

Some of these things hopefully no one would actually need, but I'm going for completeness.

If

(if #t 1 2) => 1
(if #f 1 2) => 2

And (Short circuits!)

(dm out-true (da-msg|<str>)
  (msg out da-msg)
  #t)
(dm out-false (da-msg|<str>)
  (msg out da-msg)
  #f)
(and (out-true "A")
     (out-false "B")
     (out-true "C"))
=> AB (with result of #f)

Or (Short circuits!)

(or (out-true "A")
    (out-false "B")
    (out-true "C"))
=> A (with result of #t)
(or (out-false "A")
    (out-true "B")
    (out-true "C"))
=> AB (with result of #t)

Great for tricks like you'd see in perl and PHP: (or (do_something) (die)) type stuff. I'm not sure whether that's going to get you lynched by the functional programming mob or not, though.

Unless

(unless #t 1) => #f
(unless #f 1) => 1

When

(when #t 1) => 1
(when #f 1) => #f

Cond

(dm guess (n|<int>)
  (cond
    ((> n 7)
       (msg out "Too High!\n"))
    ((< n 7)
       (msg out "Too Low!\n"))
    ((== n 7)
       (msg out "You got it!\n"))
    )
  )

Case

(dm guess (n|<int>)
  (msg out (case n
             ((1 2 3 9 10) "Good lord you're far off!")
             ((4 5) "Getting closer!")
             ((6 8) "So close!")
             ((7) "You got it!")))
  (msg out "\n"))

Case-By : Case with custom test

(dc <a> (<any>))
(dc <b> (<a>))
(dc <c> (<a>))
(dc <d> (<b> <c>)) ;; Oooooh!
(dm ctest (obj|<any>)
  (msg out (case-by obj isa?
              ((<d>) "D!\n")
              ((<c>) "C!\n")
              ((<b>) "B!\n")
              ((<a>) "A!\n")))
  )
(ctest (new <d>)) => D!

(Eg, precendence happens.)

Someone else do the rest!