Hi,
a stupid example:
f: func [x [any-type!]] [1]
b: to paren! [to paren! [:f]]
ifs-for-dummies-who-play-with-fire b [positive: [print "positive"] negative:
[print "negative"] zero: [print "zero"]]
The result:
zero
== 1
Regards
Ladislav
> [EMAIL PROTECTED] wrote:
> >
> > Hi Joel,
> >
> > I am not glad, that I must disappoint you, [...]
> >
>
> Not at all! It's just that I, being a Bear of Small Brain, find it
> difficult to give up. I'm very appreciative of the feedback!
>
> I've forgotten the source, but recall the saying, "In science, a
> successful experiment teaches nothing, as only the expected result
> is obtained. One learns only when an experiment fails, providing a
> challenge for new thought."
>
> Thanks for the excellent teaching!
>
> > but see the following example:
> >
> > a: 1
> > b: to paren! [to paren! [to paren! [to paren! [a: 0 - a]]]]
> > ifs-for-dummies b [negative: ["Negative"] zero: ["Zero"] positive:
> > ["Positive"]]
> > == "Zero"
> >
> > I think, you should read Exception #5 for Word Evaluation of my
> > Rebol/Core User's Guide Comments once again [...]
> >
>
> Have done.
>
> >
> > and hope, that this will be interesting even for others...
> >
>
> I also.
>
> Trying yet again, (I'm running the risk of keeping two distinct issues
> entangled here -- the get-to-the-bottom-of-a-strange-selector puzzle,
> and the object-for-named-parameters gimmick)...
>
> unravel: func [[throw] exp /local val] [
> val: exp
> while [not any[ number? val char? val money? val time? val]]
> [
> val: do val ]
> val ]
>
> signed-choice: make object! [
> positive: []
> negative: []
> zero: []
> selector: 0
> compute: func [[throw] selexpr] [
> selector: unravel selexpr
> either positive? selector [
> do positive
> ][
> either negative? selector [
> do negative
> ][
> do zero
> ] ] ] ]
>
> ifs-for-dummies-who-play-with-fire: func [
> [throw] selexp conseq [block!] /local actor
> ][
> actor: make signed-choice conseq
> actor/compute selexp ]
>
> After which I can conduct more experiments...
>
> >> c: [{[{[{"-1"}]}]}]
> == [{[{[{"-1"}]}]}]
> >> ifs-for-dummies-who-play-with-fire c [
> positive: ["+"] negative: ["-"] zero: ["0"]]
> == "-"
> >> c: [{[{[{"1"}]}]}]
> == [{[{[{"1"}]}]}]
> >> ifs-for-dummies-who-play-with-fire c [
> positive: ["+"] negative: ["-"] zero: ["0"]]
> == "+"
> >> c: [{[{[{"2 - 2"}]}]}]
> == [{[{[{"2 - 2"}]}]}]
> >> ifs-for-dummies-who-play-with-fire c [
> positive: ["+"] negative: ["-"] zero: ["0"]]
> == "0"
> >>
>
> >
> > I am afraid, that Signed-if-for-dummies may become a victim of the GC
bug
> > and similar issues, when used recursively...
> >
>
> I haven't had time to play with that issue, but will do so when I can.
>
> Thanks again!
>
> -jn-
>
>
>
