[XeTeX] Using the Unicode prime character (Was re. Single glyphs from a font)
Joel C. Salomon
joelcsalomon at gmail.com
Wed Jun 10 00:22:35 CEST 2009
>
>> I suppose the fix for this would be to redefine the \mathcode"8000 macro
>> for ['] so that it directly evaluates to [′]. Or just to avoid the $x'$
>> form and directly use $x\prime$ or $x′$.
>
> I'd not mess with the \mathcode of ['].
> You'll surely break multiple primes. See my attached image.
>
> If you want to mess with anything, do some tracing to look at how
> $f''$ expands. Hook into the internal macros rather than change
> the user-interface.
Tried this with PDFLaTeX:
\documentclass{minimal}
\begin{document}
${\tracingall x''}$
\end{document}
Could not make sense of the trace:
{the letter x}
{the character '}
'->^\bgroup \prim at s
{superscript character ^}
\prim at s ->\prime \futurelet \@let at token \pr at m@s
{\mathchar"230}
{\futurelet}
\pr at m@s ->\ifx '\@let at token \expandafter \pr@@@s \else \ifx ^\@let at token
\expandafter \expandafter \expandafter \pr@@@t \else \egroup \fi \fi
{\ifx}
{true}
{\expandafter}
{\else}
\pr@@@s #1->\prim at s
#1<-'
\prim at s ->\prime \futurelet \@let at token \pr at m@s
{\mathchar"230}
{\futurelet}
\pr at m@s ->\ifx '\@let at token \expandafter \pr@@@s \else \ifx ^\@let at token
\expandafter \expandafter \expandafter \pr@@@t \else \egroup \fi \fi
{\ifx}
{false}
{\ifx}
{false}
{end-group character }}
{restoring \@let at token=begin-group character {}
{\fi}
{\fi}
{end-group character }}
I have very little idea of what this all means (though Ross’s
explanation of the look-ahead is somewhat enlightening), and almost no
idea where to start hooking things into the internal macros. I can
guess it would involve redefining one or more of \prim at s, \pr at m@s,
\pr@@@s, and \pr@@@t., but beyond that…
—Joel Salomon
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