Re: Pringsheim Notation for continued fractions

Thanks, Florent, 

The vertical bars look good, but the numerators and denominators are placed flush left instead of centered, which looks odd in cases like \cFrac{99999}{1}. 

Matthias

> On Jun 14, 2026, at 1:13 PM, Florent Michel <[email protected]> wrote:
> 
> Hi, 
> 
> This is a bit of a hack (and I'm sure there are better solutions), but maybe something like the following? 
> 
> \define[2]\cFrac{%
> \vcenter{
>   \newdimen\WidthOfFirst
>   \newdimen\WidthOfSecond
>   \newdimen\TrueWidth
>   \WidthOfFirst=\widthofstring{\strut$#1$\,}
>   \WidthOfSecond=\widthofstring{\strut\vrule\,$#2$}
>   \startluacode
>     trueWidth = math.max(tex.dimen.WidthOfFirst, tex.dimen.WidthOfSecond)
>     context("\\TrueWidth=" .. trueWidth .. "sp")
>   \stopluacode
>   \hbox{\offset[width=\TrueWidth]{\strut$#1$\,}\vrule}\hrule\hbox{\strut\vrule\,$#2$}}%
> }
> 
> \starttext
> \startformula
> \startalign
> \NC  a_0+a_0a_1+a_0 a_1 a_2+a_0 a_1 a_2 a_3 \NC  = \cfrac{a_0}{1-\cfrac{a_1}{1+a_1-\cfrac{a_2}{1+a_2-\cfrac{a_2}{1+a_2-\cfrac{a_3}{1+a_3-\cdots}}}}}\NR
> %\NC   \NC  = \frac{a_0|}{|1}-\frac{a_1|}{|1+a_1}-\frac{a_2|}{|1+a_2}-\frac{a_3|}{|1+a_3}-\cdots\NR
> \NC   \NC  = \cFrac{a_0}{1}-\cFrac{a_1}{1+a_1}-\cFrac{a_2}{1+a_2}-\cFrac{a_3}{1+a_3}-\cdots\NR
> \stopalign
> 
> \stopformula
> \stoptext
> 
> Cheers,
> Florent
> 
> Le dim. 14 juin 2026 à 17:26, Matthias Weber <[email protected] <mailto:[email protected]>> a écrit :
>> Dear All, 
>> 
>> 
>> I would like to typeset continued fractions as attempted and failed in the second line of the following MWE:
>> 
>> \def\cFrac#1#2{%
>> \vcenter{\hbox{\strut$#1$\,\vrule}\hrule\hbox{\strut\vrule\,$#2$}}}
>> 
>> \starttext
>> \startformula
>> \startalign
>> \NC  a_0+a_0a_1+a_0 a_1 a_2+a_0 a_1 a_2 a_3 \NC  = \cfrac{a_0}{1-\cfrac{a_1}{1+a_1-\cfrac{a_2}{1+a_2-\cfrac{a_2}{1+a_2-\cfrac{a_3}{1+a_3-\cdots}}}}}\NR
>> %\NC   \NC  = \frac{a_0|}{|1}-\frac{a_1|}{|1+a_1}-\frac{a_2|}{|1+a_2}-\frac{a_3|}{|1+a_3}-\cdots\NR
>> \NC   \NC  = \cFrac{a_0}{1}-\cFrac{a_1}{1+a_1}-\cFrac{a_2}{1+a_2}-\cFrac{a_3}{1+a_3}-\cdots\NR
>> \stopalign
>> 
>> \stopformula
>> \stoptext
>> 
>> 
>> The macro is from 
>> 
>> https://tex.stackexchange.com/questions/68190/how-do-i-typeset-continued-fractions-in-pringsheims-concise-notation
>> 
>> where this question is discussed for LaTeX.
>> 
>> Unfortunately, the vertical bars on the top of the fractions do not align with the right end of the fraction bar.
>> 
>> 
>> Any suggestions?
>> 
>> Thanks,
>> 
>> Matthias
>> 
>> 
>> 
>> 
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maillist : [email protected] / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
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