{The first time I tried to reply to Andrew's message, my mail server
glitched in a way that seemed to indicate losing my reply. If this
is a duplicate, I apologize.}
[EMAIL PROTECTED] wrote:
>
> >> e: ['e pick ['f 'g] random length? third e]
> == ['e pick ['f 'g] random length? third e]
> >> print e
> e f
> >> print e
> e g
> >> print e
> e g
> >> print e
> e g
> >> print e
> e f
Aha! A non-deterministic finite-state automaton written in REBOL!
> == [reduce replace [#"e" #"f" + 1] last third e to-integer even? last
> third e]
> >> print e
> e f
> >> e
> == [reduce replace [#"e" #"f" + 0] last third e to-integer even? last
> third e]
You guys have been so ingenious, I'm almost embarrased to show my
two solutions.
My original version requires just a bit of set-up...
>> f: [e: g]
== [e: g]
>> g: [e: f]
== [e: f]
>> e: f
== [e: g]
after which...
>> print e
e f
>> print e
e g
>> print e
e f
When I gave the hint about "without modifying another variable", I was
actually trying to hint about modifying e. However, I realized later
that someone might think it was misleading, as I use f and g at the
global level. To solve that potential objection...
>> e: use [f g] [f: [e: g] g: [e: f] f]
== [e: g]
>> print e
e f
>> print e
e g
>> print e
e f
>> f: "uninvolved global variable"
== "uninvolved global variable"
>> g: "another innocent bystander"
== "another innocent bystander"
>> print e
e g
>> print e
e f
-jn-
