Hi, Hans. I've got a question. Negative steps are treated as positive:

\starttext
\expandedloop 10 0 -2 {\the\currentloopiterator\ }
\stoptext

gives

0 2 4 6 8 10

Is this expected behavior? If so, it would be fine to have something more
alike to MetaPost's "for ... step ... until" loop. Thank you in advance.

Regards,

Jairo

El vie, 3 dic 2021 a la(s) 09:29, Hans Hagen via ntg-context (
ntg-context@ntg.nl) escribió:

> Hi,
>
> a new upload
>
> - some keywords renamed in the engine and therefore more split between
> mkiv and lmtx (hopefully i included all files) .. if something doesn't
> work any more it might be because i missed a rename.
>
> - i finally decied that it does make sense to have native loops at the
> primitive level (after all, metapost as macro language also has them)
> and although much is possible in macros it doesn't mean we have to do it
> the (often ugly and showing-off-by-abusing-side-effects way).
>
> We have just a constructor:
>
>    \unexpandedloop      1 100 1 {.}
>
> and a fully expandable one for e.g. use in \edef:
>
>    \expandedloop        1 100 1 {.}
>
> plus an also fully expandable one for anywhere but with potential side
> effects (out of order local loops):
>
>    \localcontrolledloop 1 100 1 {.}
>
> complemented by a few status primitives (integers, use \the or \number
> to serialize them):
>
>    \currentloopiterator
>    \currentloopnesting
>
> and a quitter that aborts at the next iteration:
>
>    \quitloop
>
> as usual it's experimental for a while. Among the rationales are 'less
> tracing clutter', 'performance' and 'more natural primitive tex coding'
> (but that one is personal).
>
> Hans
>
> -----------------------------------------------------------------
>                                            Hans Hagen | PRAGMA ADE
>                Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
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