Re: recursion

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