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From: sjack@dontemail.me (sjack)
Newsgroups: comp.lang.forth
Subject: Re: recursion
Date: Tue, 16 Jul 2024 19:39:11 -0000 (UTC)
Organization: A noiseless patient Spider
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minforth <minforth@gmx.net> wrote:
> Pretzel coding. I wondered what that could be useful for.

Kind of wonder why myself; more focused on ways to do the given
example rather than why it's needed to be a forward case. By the
way, the macro example I gave wasn't right; see example 5 for 
correct way. Example 4 seems to me the most proper way as it
uses all basic Forth elements. Example 3 seems the best but it's
not a forwarding case so it may not be applicable to what's 
being sought.

Example 1 
: bar dup . 1- [ here tmp! ] noop ;
: foo dup 0> if bar [ latest pfa cfa tmp@ ! ] else drop then ;
5 foo5 4 3 2 1 

Example 2 
: forward here tmp! 0 , ; immediate
: resolve latest pfa cfa tmp@ ! ; immediate 
: bar dup . 1- forward ;
: foo dup 0> if bar resolve else drop then ;
5 foo5 4 3 2 1 

Example 3 
: bar dup . 1- ;
: foo dup 0> if bar myself else drop then ;
5 foo5 4 3 2 1 

Example 4 
defer foo
: bar dup . 1- foo ;
anon dup 0> if bar else drop then ; is foo
5 foo5 4 3 2 1 

Example 5 
"here tmp! 0 ," /mm: forward
"latest pfa cfa tmp@ !" /mm: resolve
: bar dup . 1- [ mm forward ] ;
: foo dup 0> if bar [ mm resolve ] else drop then ;
5 foo5 4 3 2 1 
-- remove all macros
mm.clear
-- do again
5 foo5 4 3 2 1 

--
me