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Diffstat (limited to 'tex/context/base/math-ini.tex')
| -rw-r--r-- | tex/context/base/math-ini.tex | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/tex/context/base/math-ini.tex b/tex/context/base/math-ini.tex index 1957ab0d7..200d23d98 100644 --- a/tex/context/base/math-ini.tex +++ b/tex/context/base/math-ini.tex @@ -710,6 +710,49 @@ %D \showmathtoken{Gamma} $\Gamma \Delta \alpha \delta \zeta$ %D \stoptyping +%D \macros +%D {nonknuthmode, donknuthmode} +%D +%D The underscore is frequently used in manuals but unfortunately \TEX\ prefers +%D it to be a math specific character. And since computer modern fonts didn't +%D have an underscore, one had to use commands to fake one. Nowadays we do +%D have underscores in latin modern, and since all other fonts have them, we +%D decided to get away from the restriction to use the underscore character in +%D text mode. +%D +%D \starttyping +%D \def\test#1{#1} +%D +%D \nonknuthmode $x_2$ x_2 \test{$x_2$} \test{x_2} +%D +%D \donknuthmode $x_2$ x_2 \test{$x_2$} \test{x_2} +%D \stoptyping +%D +%D The result is as expected: the first line typesets ok, while the second +%D one triggers an error message. + +\bgroup + + \ifx\normalsuber\undefined \def\normalsuber{_} \fi + \ifx\normalsuper\undefined \def\normalsuper{^} \fi + + \catcode`_=\active + \catcode`^=\active + + \gdef\nonknuthmode + {\appendtoks\let_\normalsuber\let^\normalsuper\to\everymathematics + \mathcode`_="8000 + \mathcode`^="8000 + \catcode`_=\@@other + \catcode`^=\@@other + \let\nonknuthmode\relax} + + \gdef\donknuthmode + {\catcode`_=\@@subscript + \catcode`^=\@@superscript} + +\egroup + \protect \endinput \tracemathcollectiontrue |