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From: Helmar Wodtke <helmwo@gmail.com>
Newsgroups: comp.lang.forth
Subject: Re: How about helping optimization in language?
Date: Tue, 27 Mar 2012 11:29:51 -0700 (PDT)
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Am Dienstag, 27. M=E4rz 2012 19:27:48 UTC+2 schrieb Andrew Haley:
> Helmar Wodtke <helmwo@gmail.com> wrote:
> > Am Dienstag, 27. M?rz 2012 18:34:56 UTC+2 schrieb Andrew Haley:
> >> Helmar Wodtke <helmwo@gmail.com> wrote:
> >> > Am Dienstag, 27. M?rz 2012 16:32:50 UTC+2 schrieb Andrew Haley:
> >> >> Helmar Wodtke <helmwo@gmail.com> wrote:
> >> >> >=20
> >> >> > ">R" (especially in ANS terms) means to bring something to a seco=
nd
> >> >> > "stack". "R>" to bring it back. This could be virtually something
> >> >> > like a register at the machine you have.
> >> >> >=20
> >> >> > Why not implement this more elaborate about what ">R" means? I kn=
ow
> >> >> > CS-ROLL etc. - it should not be this weird.  How about defining "=
>R"
> >> >> > has nothing to do with return stack but it could affect it?
> >> >>=20
> >> >> That is how >R is defined, and has been since '94.  Have a look.
> >> >=20
> >> > yes I know. But how about looking at real world challenges people
> >> > get here in C.L.F. and are not able to solve?=20
> >>=20
> >> It's hard to do that without a specific example.
> >=20
> > The basic question was: how to find two of three values on stack
> > that are bigger than the smallest one.
> >=20
> > ( a b c -- d e -- d, e are the maximums values of a b c)
> > : 2of3 2dup max >r min max r> ;
> >=20
> > This would be my "thumb simplification" of the thing.
>=20
> That is a very pretty solution.

The sequence "max >r min" is not really pretty. It is nice - but it depends=
 on implementation of the Forth system if this is a good solution. This is =
about what I was talking about >R and R> - a lot depends on interpretation =
of the system. If the system has a register left, why should >R be a stack =
in this small thing? It could go to the register as long as I keep it stabl=
e ;) Well, some flow control words would disturb the optimizations probably=
.

Regards,
-Helmar

> Andrew.