Différences

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

--- 2_programmation:macros:que_sont_les_environnements [2018/05/23 20:28]
joseph.wright
+++ 2_programmation:macros:que_sont_les_environnements [2021/07/06 07:06]
jejust Compilation du code d'un exemple.
@@ Ligne 1: / Ligne 1: @@
----
+====== What are LaTeX “environments”? ======
-ID: Q-whatenv
-section: Bits and pieces of (La)TeX
-revised: 2014-06-10
----
-# What are LaTeX ''environments''
-While TeX makes direct provision for commands, LaTeX adds a
-concept of ''environment''; environments perform an action on a block
+While TeX makes direct provision for commands, LaTeX adds a concept of "environment".
-(of something or other) rather than than just doing something at one
+Environments perform an action on a block (of something or other) rather than just doing something at one
 place in your document.
 A totally trivial environment could change the font in use for a chunk
 of text, as
-```latex
+<code latex>
 \newenvironment{monoblock}%
   {\ttfamily}%
   {}
-```
+</code>
-which defines a `monoblock` which may be used as
+which defines a ''monoblock'' environment which may be used as:
-```latex
+<WRAP column 50ex>
+<code latex>
 \begin{monoblock}
-  some text set in monospace
+  Some text set in monospace.
 \end{monoblock}
-```
+</code>
-which will look like:
+</WRAP>
-  `some text set in monospace`
+<WRAP column 30ex>
-so it is a particularly simple example.  A rather complicated
+<latexdoc>
-environment is introduced by `\begin{document}`; it looks
+\documentclass{article}
+  \usepackage{lmodern}
+  \pagestyle{empty}
+\newenvironment{monoblock}%
+  {\ttfamily}%
+  {}
+\begin{document}
+\large
+\begin{monoblock}
+  Some text set in monospace.
+\end{monoblock}
+\end{document}
+</latexdoc>
+</WRAP>
+<WRAP clear />
+It is a particularly simple example.  A rather complicated
+environment is introduced by ''\begin{document}''; it looks
 simple, but needs all sorts of special TeX code to make it work
-''transparently''; most environments are more elaborate than
+"transparently"; most environments are more elaborate than
-`monoblock` and _much_ simpler than
+''monoblock'' and //much// simpler than ''document''.
-`document`.
-An environment puts its content inside a TeX _group_, so that
+An environment puts its content inside a TeX //group//, so that
-commands used inside the environment don't ''leak out''&nbsp;&mdash; the
+commands used inside the environment don't "leak out" --- the
-`monoblock` environment, above, restricts its effect to
+''monoblock'' environment, above, restricts its effect to
-its own contents (the stuff between the `\begin{monoblock}`
+its own contents (the stuff between the ''\begin{monoblock}''
-and `\end{monoblock}`), which is just what you need for this
+and ''\end{monoblock}''), which is just what you need for this
 sort of thing.
-So that's ''simple'' environments; the `monoblock`, above
+So that's "simple" environments; the ''monoblock'', above
 doesn't actually gain us much over
-```latex
+<code latex>
 {\ttfamily some text set in monospace}
-```
+</code>
-though in fact many useful environments are just as simple (to look
+though in fact many useful environments are just as simple (to look at).
-at).  Some, such as `verbatim`, look simple but are
+Some, such as ''verbatim'', look simple but are actually very tricky inside.
-actually very tricky inside.
 LaTeX also allows arguments to an environment:
-```latex
+<code latex>
 \newenvironment{fontblock}[1]%
   {#1\selectfont}%
   {}
-```
+</code>
-and use of `fontblock` as:
+and use of ''fontblock'' as:
-```latex
+<code latex>
 \begin{fontblock}{\ttfamily}
-```
+</code>
-would produce the same effect as the `monoblock`
+would produce the same effect as the ''monoblock'' environment.
-environment.
 Environments may also have optional arguments, in much the same way as
 commands:
-```latex
+<code latex>
 \newenvironment{normaltext}[1][\itshape]%
   {#1}%
   {}
-```
+</code>
 which will ordinarily set its body in italic, but
-```latex
+<code latex>
 \begin{normaltext}[\ttfamily]
   ...
 \end{normaltext}
-```
+</code>
 will observe its optional argument, and behave the same as the
-`monoblock` we started with.
+''monoblock'' we started with.
 Note that an environments argument(s) (mandatory or optional) are
-_not_ passed to the `\end` text of the environment&nbsp;&mdash; that
+//not// passed to the ''\end'' text of the environment --- that
 is specified as a macro with no arguments, so that
-```latex
+<code latex>
 \newenvironment{normaltext}[1][\itshape]%
   {#1}%
   {\typeout{what was #1, again?}
-```
+</code>
 produces an error message
-```latex
+<code text>
 ! Illegal parameter number in definition of \endnormaltext.
-```
+</code>
 So, if you need to pass an environment argument to the end-code, you
 have to wrap it in a macro of its own:
-<!-- {% raw %} -->
-```latex
+<code latex>
 \newenvironment{normaltext}[1][Intro]%
   {#1%
    \newcommand{\foo}{#1}}%
   {\typeout{what was \foo{}, again?}
-```
+</code>
-<!-- {% endraw %} -->
+-----
+//Source:// [[faquk>FAQ-whatenv|What are LaTeX “environments”]]
+{{htmlmetatags>metatag-keywords=(LaTeX,programmation,environnements personnalisés)
+metatag-og:title=(What are LaTeX “environments”?)
+metatag-og:site_name=(FAQ LaTeX francophone)
+}}