Hans Hagen j.hagen at xs4all.nl
Sat Jan 15 17:45:07 CET 2022

```On 1/15/2022 3:52 PM, Alexandre Christe via ntg-context wrote:
> Just came across a weird behavior with the latest upload.
>
> The following doesn't print as it should
> \startformula 4^{2x} - 4^x - 25 = 0 \stopformula
>
> I don't think it's normal (I see the spacing to make room for anything
> that comes after the first character in the exposant, but it is not
> printed).

to get an idea about default and additional spacing in tex ...

\starttext

\startbuffer
\dontleavehmode\ruledhbox{\$x^2 + x\$}\par
\dontleavehmode\ruledhbox{\$x_2 + x\$}\par
\dontleavehmode\ruledhbox{\$x^^2 + x\$}\par
\dontleavehmode\ruledhbox{\$x__2 + x\$}\blank
\stopbuffer

\startTEXpage[offset=3pt]
\getbuffer
\Umathspaceafterscript \textstyle0pt
\Umathspacebeforescript\textstyle0pt
\getbuffer
\Umathextrasupspace    \textstyle20pt
\Umathextrasubspace    \textstyle40pt
\Umathextrasupprespace \textstyle10pt
\Umathextrasubprespace \textstyle30pt
\getbuffer
\stopTEXpage

\stoptext

so by default there is space added to scripts (more in latin modern than
in cmr btw as it is font driven) but one can argue if that makes sense
at all ... this is why we might default to zero font spacing and
specific super/subscript spacing instead (just as in lmtx we have
prescripts and related (fake opentype) spacing)

in a similar fashion there is built-in pre/post fraction spacing that
makes that we cannot have tight fractions (by default) while in fact
that has to be driven by proper fraction-class spacing so that's another
thing that might happen: tight fractions + proper interclass spacing
(because we have less memory constraints than when tex showed up we can

(i bet that due to a 'tex does perfect math syndrome' these thinsg go
unnoticed (not by DEK himself, just look at the chapters on finetunign
math) ... some of it is also compensate for the width-of-glyph cheating
that goes on in the traditional engine but that is another matter

Hans

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