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Ci-dessous, les différences entre deux révisions de la page.

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+====== Comment mettre des caractères autres que des lettres dans les noms de commande ? ======
+Les utilisateurs débutants avec <latex>\LaTeX</latex> sont souvent étonnés de voir que des commandes contenant des caractères autres que des lettres ne fonctionnent pas. Par exemple :
+<code latex>
+\newcommand{\a2main}{À demain !}
+</code>
+En effet, contrairement à d'autres langages de programmation, <latex>\TeX</latex> n'autorise que [[2_programmation:macros:que_sont_les_macros|des lettres dans les noms de commandes]]. Il existe cependant des techniques pour contourner cette limitation mais elles ne sont pas sans défaut.
+===== Utilisation de “\csname” et “\endcsname” =====
+Voici un exemple de la méthode utilisant les commandes ''\csname'' et ''\endcsname''.
+<code>
+\expandafter\newcommand\csname a2main\endcsname{À demain !}
+Je vous dis « \csname a2main\endcsname ».
+</code>
+Cette technique a l'unique désavantage de demander d'être bien trop verbeuse.
+FIXME //Traduction à poursuivre.//
+. Define a "special-command generator", and  use the resulting commands:
+<code latex>
+\newcommand{\DefineRemark}[2]{%
+  \expandafter\newcommand\csname rmk-#1\endcsname{#2}%
+}
+\newcommand{\Remark}[1]{\csname rmk-#1\endcsname}
+ ...
+\DefineRemark{cul8r}{Goodbye!}
+ ...
+\Remark{cul8r}
+</code>
+  * **Pro:** Straightforward to use, not too untidy
+  * **Con:** It's hardly doing what we set out to do (experts will see that you are defining a macro, but others likely won't)
+. Convince TeX that ''8'' is a letter:
+<code latex>
+\catcode`8 = 11
+\newcommand{\cul8r}{Goodbye!}
+I said, ``\cul8r''.
+</code>
+  * **Pro:** ''\cul8r'' can be used directly
+  * **Con:** Likely to break other uses of ''8'' (such as numbers or dimensions; so ''\setlength{''\paperwidth''}{8in}'' tells us:
+<code>
+! Missing number, treated as zero.
+<to be read again>
+</code>
+As a general rule, changing category codes is something to use
+//in extremis//, after detailed examination of options.  It is
+conceivable that such drastic action could be useful for you, but
+most ordinary users are well advised not even to try such a technique.
+.  Define a macro ''\cul'' which must always be followed by ''8r'':
+<code>
+\def\cul8r{Goodbye!}
+I said, ``\cul8r''.
+</code>
+  * **Pro:** ''\cul8r'' can be used directly
+  * **Con #1:** Breaks if ''\cul'' is followed by anything other than ''8r'', with a confusing diagnostic, as ''\cul99'' produces:
+<code>
+! Use of \cul doesn't match its definition.
+<*> \cul9
+</code>
+(which would confuse someone who hadn't even realised there //was// a definition of ''\cul'' in the document).
+  * **Con #2:** Silently redefines existing ''\cul'', if any; as a result, the technique cannot be used to define both a ''\cul8r'' and, say, a ''\cul123'' macro in the same document.
+Technique 3 is in fact commonly used --- in a limited form --- within
+most LaTeX packages and within LaTeX itself.  The convention is to
+use ''@'' within the names of internal macros to hide them
+from the user and thereby prevent naming conflicts.  To this end,
+LaTeX automatically treats ''@'' as a letter while
+processing classes and packages and as a non-letter while processing
+the user's document.  The key to this technique is the separation:
+internally a non-letter is used for macro names, and the user doesn't
+see anything of it, while the status remains "frozen" in all the
+definitions created within the class or package.  See
+[[FAQ-atsigns|\@ and @ in macro names]] for
+more information.
+Note that analogous use of technique 3 in this example would give us
+<code latex>
+\begingroup
+  \catcode`8 = 11
+  \gdef\cul8r{Goodbye!}
+  \gdef\later{\cul8r}
+\endgroup
+I said, ``\later''.
+</code>
+which works, but rather defeats the object of the exercise.
+(''\later'' has the "frozen" catcode for "8", even though the value
+has reverted to normal by the time it's used; note, also, the use of
+the primitive command ''\gdef'', since ''\newcommand'' can't make a
+macro that's available outside the group.)
+//Recommendation//: Either choose another mechanism (such as
+''\DefineRemark'' above), or choose another name for your macro, one
+that contains only ordinary letters.  A common approach is to use
+roman numerals in place of arabic ones:
+<code latex>
+\newcommand{\culVIIIr}{Goodbye!}
+</code>
+which rather spoils the intent of the joke implicit in the example ''\cul8r''!
+-----
+//Source:// [[faquk>FAQ-linmacnames|Non-letters in macro names]]
+{{htmlmetatags>metatag-keywords=(LaTeX,programmation)
+metatag-og:title=(Comment mettre des caractères autres que des lettres dans les noms de commande)
+metatag-og:site_name=(FAQ LaTeX francophone)
+}}