[NTG-context] \Umathcodenum and get...dir in lmtx

[Hans Hagen]

On 5/28/2020 4:03 PM, Marcel Fabian Krüger wrote:
> Hi,
> 
> I had two issues with luametatex:
> 
> The manual documents getters and setters for the directions:
> 
> The direction states can be queried and set with:
> tex.gettextdir() tex.getpardir()          tex.setmathdir(<number>)
> tex.getlinedir() tex.settextdir(<number>) tex.setpardir(<number>)
> tex.getmathdir() tex.setlinedir(<number>)
> 
> While there is no problem with the set...dir commands, the get...dir
> commands don't actually exists. (They can be implemented using tex.get,
> but it would be nice if either they were added to luametatex or if they
> were removed from te documentation to avoid confusion.)

they're cheap to add (but linedir is just text dir and boxdir can be get 
otherwise as with all these other box properties)

> Additionally the scanning variant of \Umathcodenum seems broken:
> 
> Take the example document
> 
> \starttext
> \directlua{
>    print('gettextdir:', tex.gettextdir)
> }
> \the\Umathcodenum`a
> \stoptext
> 
> It works in ConTeXt mkiv, but in lmtx it shown a (non-informative) error:
> 
>    gettextdir:	nil
> 
>    tex error       > tex error on line 5 in file ./contfail.tex: ! This can't happen (scan char)

the scanning part is ok, but the serializer ignores that one (i'll add it)

>    l.5 \the\Umathcodenum`a
>                         
> 
>    1     \starttext
>    2     \directlua{
>    3       print('gettextdir:', tex.gettextdir)
>    4     }
>    5 >>  \the\Umathcodenum`a
>    6     \stoptext
>    7
> 
> 
>    I'm broken. Please show this to someone who can fix me.
> 
> 
>    mtx-context     | fatal error: return code: 256
> 
> (\Umathcodenum`a=123 seems to work though)
> 
> Also especially these "This can't happen" errors a a it of pain debug
> without having the option to look into the source which I can't find

normally can't happens are not supposed to show up in a run as they 
indicate a not-yet-taken-care-of situation (which can happen when one 
adds a primitive)

> anywhere. Has that been released? Is it still planned to make it
> available at some point?
sure, when we have organized the repositories which is part of a larger 
reorganization effort which takes time (and motivation) which is kind of 
fuzzy this year (i originally planned early this year, then around bt, 
now we're somewhat later .. we'll see when)

Hans


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