[NTG-context] \ifnum with two \recurselevel

[NTG-context] \ifnum with two \recurselevel

[Pablo Rodriguez via ntg-context]

Dear list,

I have the following sample code:

  \starttext
  \startTEXpage[offset=1dk]
  \dostepwiserecurse{2}{6}{1}{\edef\AbC{\recurselevel}%
  \dostepwiserecurse{2}{7}{1}{%\AbC.\recurselevel\ /\
  \ifnum\AbC < \recurselevel%
  \AbC:\recurselevel\ \|\|
  \fi}
  \\}
  \stopTEXpage
  \stoptext

I would like to only get the numbers in the form first:second loops if
and only if the value of the first loop is less than the value from the
second loop.

I think this should be simple, but I don’t get it with any of these
conditionals:

   \ifnum\AbC < \recurselevel

   \ifnum\recurselevel > \AbC

Sorry for the stupid question, but what I am missing here?

Many thanks for your help,

Pablo
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[NTG-context] Re: \ifnum with two \recurselevel

[Hans Hagen via ntg-context]

On 5/8/2025 7:02 PM, Pablo Rodriguez via ntg-context wrote:
> Dear list,
> 
> I have the following sample code:
> 
>    \starttext
>    \startTEXpage[offset=1dk]
>    \dostepwiserecurse{2}{6}{1}{\edef\AbC{\recurselevel}%
>    \dostepwiserecurse{2}{7}{1}{%\AbC.\recurselevel\ /\
>    \ifnum\AbC < \recurselevel%
>    \AbC:\recurselevel\ \|\|
>    \fi}
>    \\}
>    \stopTEXpage
>    \stoptext
> 
> I would like to only get the numbers in the form first:second loops if
> and only if the value of the first loop is less than the value from the
> second loop.
> 
> I think this should be simple, but I don’t get it with any of these
> conditionals:
> 
>     \ifnum\AbC < \recurselevel
> 
>     \ifnum\recurselevel > \AbC
> 
> Sorry for the stupid question, but what I am missing here?
> 
> Many thanks for your help,

These % after the comparison make tex scan on for the end of a number (a 
\relax of space ends the scan). You can do this:

\starttext
\startTEXpage[offset=1dk]
\dostepwiserecurse{2}{6}{1}{%
     \dostepwiserecurse{2}{7}{1}{%
         \ifnum#1<##1\relax
             #1:##1\ \|\|%
         \fi
     }%
      \\%
}
\stopTEXpage
\stoptext

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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[NTG-context] Re: \ifnum with two \recurselevel

[Pablo Rodriguez via ntg-context]

On 5/8/25 21:02, Hans Hagen via ntg-context wrote:
> [...]
> These % after the comparison make tex scan on for the end of a number (a 
> \relax of space ends the scan). You can do this:

Many thanks for your reply, Hans.

With your sample, I see that some crazy things (such as the following)
are possible:

  \starttext
  \dorecurse{2}{%
    \dorecurse{3}{%
      \dorecurse{4}{%
        \dorecurse{5}{%
          \dorecurse{6}{%
            #1:##1:####1:########1:################1 }\\
  }\blank[.25st]}\blank[.5st]}\blank[1st]}
  \stoptext

I mean, accessing different levels of recursion in nested loops.

Being a very special trick for really corner cases, is there something
to be considered when using it?

Many thanks for your help,

Pablo
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[NTG-context] Re: \ifnum with two \recurselevel

[Hans Hagen]

On 5/9/2025 5:41 AM, Pablo Rodriguez via ntg-context wrote:
> On 5/8/25 21:02, Hans Hagen via ntg-context wrote:
>> [...]
>> These % after the comparison make tex scan on for the end of a number (a
>> \relax of space ends the scan). You can do this:
> 
> Many thanks for your reply, Hans.
> 
> With your sample, I see that some crazy things (such as the following)
> are possible:
> 
>    \starttext
>    \dorecurse{2}{%
>      \dorecurse{3}{%
>        \dorecurse{4}{%
>          \dorecurse{5}{%
>            \dorecurse{6}{%
>              #1:##1:####1:########1:################1 }\\
>    }\blank[.25st]}\blank[.5st]}\blank[1st]}
>    \stoptext
> 
> I mean, accessing different levels of recursion in nested loops.
> 
> Being a very special trick for really corner cases, is there something
> to be considered when using it?

only imagination ... try #2 ##2 etc .. these #1 things are basically 
references to macro arguments

\dorecurse{1}{%
     \dorecurse{3}{%
         \dorecurse{3}{%
             \dorecurse{3}{%
                 \dorecurse{3}{%
                   % #1:##1:####1:########1:################1
                     #2:##2:####2:########2:################2
                 }\\
             }
             \blank[.25st]
         }
         \blank[.5st]
     }
     \blank[1st]
}

\page

or go wild with

\localcontrolledrepeat 1 {
     \localcontrolledrepeat 3 {
         \localcontrolledrepeat 3 {
             \localcontrolledrepeat 3 {
                 \localcontrolledrepeat 3 {
                     \the\previousloopiterator4:%
                     \the\previousloopiterator3:%
                     \the\previousloopiterator2:%
                     \the\previousloopiterator1:%
                     \the\previousloopiterator0 %
                 }\\
             }
             \blank[.25st]
         }
         \blank[.5st]
     }
     \blank[1st]
}

\page

or maybe:

\edef\foo{%
\expandedrepeat 1 {
     \expandedrepeat 3 {
         \expandedrepeat 3 {
             \expandedrepeat 3 {
                 \expandedrepeat 3 {
                     \the\previousloopiterator4:%
                     \the\previousloopiterator3:%
                     \the\previousloopiterator2:%
                     \the\previousloopiterator1:%
                     \the\previousloopiterator0 %
                 }\\
             }
             \blank[.25st]
         }
         \blank[.5st]
     }
     \blank[1st]
}
}

\foo

\meaningfull\foo

enough in there for a rainy day

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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___________________________________________________________________________________

[NTG-context] Re: \ifnum with two \recurselevel

[Pablo Rodriguez via ntg-context]

On 5/9/25 09:07, Hans Hagen wrote:
>> [...]
>> Being a very special trick for really corner cases, is there something
>> to be considered when using it?
> 
> only imagination ... try #2 ##2 etc .. these #1 things are basically 
> references to macro arguments

Many thanks for your info, Hans.

I would have never discovered this by myself.

Pablo
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