Ceci est une ancienne révision du document !
— ID: Q-moren9 revised: 2014-06-10 — # How to break the 9-argument limit
If you think about it, you will realise that Knuth's command definition syntax: ```latex \def\blah#1#2 … #9{<macro body>} ``` is intrinsically limited to just 9 arguments. There's no direct way round this: how would you express a 10th argument? — and ensure that the syntax didn't gobble some other valid usage?
If you really must have more than 9 arguments, the way to go is: <!– {% raw %} –> ```latex \def\blah#1#2 … #9{%
\def\ArgI{{#1}}%
\def\ArgII{{#2}}%
...
\def\ArgIX{{#9}}%
\BlahRelay
} \def\BlahRelay#1#2#3{%
% arguments 1-9 are now in % \ArgI-\ArgIX % arguments 10-12 are in % #1-#3 <macro body>%
} ``` <!– {% endraw %} –> This technique is easily extendible by concert pianists of the TeX keyboard, but is really hard to recommend.
LaTeX users have the small convenience of merely giving a number of arguments in the `\newcommand` that defines each part of the relaying mechanism: Knuth's restriction applies to `\newcommand` just as it does to `\def`. However, LaTeX users also have the way out of such barbarous command syntax: the [`keyval`](https://ctan.org/pkg/keyval) package. With [`keyval`](https://ctan.org/pkg/keyval), and a bit of programming, one can write really quite sophisticated commands, whose invocation might look like: <!– {% raw %} –> ```latex \flowerinstance{species=Primula veris,
family=Primulaceae, location=Coldham's Common, locationtype=Common grazing land, date=1995/04/24, numplants=50, soiltype=alkaline
} ``` <!– {% endraw %} –> The merit of such verbosity is that it is self-explanatory: the typist doesn't have to remember that argument twelve is `soiltype`, and so on: the commands may be copied from field notes quickly and accurately.
- faq-mac-prog.tex (q-keyval): tweak words about getoptk
