Ceci est une ancienne révision du document !
Comment écrire en pseudocode?
Il n'y a pas de consensus sur la bonne façon de mettre en forme du pseudocode. Par conséquent, il existe de nombreuses extensions LaTeX pour composer des pseudocodes de façon lisible et jolie.
Le pseudocode diffère des listings de programmes réels en ce qu'il n'a pas de syntaxe et de sémantique strictes. De plus, comme le pseudocode est censé exprimer un algorithme de manière claire, il peut avoir besoin d'incorporer des notations mathématiques, des figures, des tableaux et d'autres éléments LaTeX qui n'apparaissent normalement pas dans les langages de programmation conventionnels. La mise en forme des programmes est décrite ailleurs.
Vous pourriez certainement créer votre propre environnement de composition de pseudocode en utilisant,
par exemple, les environnements tabbing (décrits ici)
ou list (décrits ici) — ce ne serait pas très difficile pour commencer,
mais vous arriverez vite à un niveau de complexité rédhibitoire.
Cela vaut donc la peine d'essayer les extensions suivantes, toutes conçues spécifiquement pour la mise en forme de pseudocodes.
The algorithms bundle (which contains packages algorithm and algorithmic, both of which are needed for ordinary use) has a simple interface and produces fairly nice output. It provides primitives for statements, which can contain arbitrary LaTeX commands, comments, and a set of iterative and conditional constructs. These primitives can easily be redefined to produce different text in the output. However, there is no support for adding new primitives. Typesetting the pseudocode itself is performed in algorithmic; the algorithms package uses the facilities of the float package to number algorithms sequentially, enable algorithms to float like figures or tables, and support including a List of Algorithms in a document's front matter.
Packages in the algorithmicx bundle are similar both in concept and output form to algorithmic but additionally provide support for adding new keywords and altering the formatting. It provides the algpseudocode package which is (almost) a drop-in replacement for algorithmic. Another package in the bundle, algpascal, uses Pascal-like keywords, indents differently from algpseudocode, and puts command arguments in maths mode instead of text mode. There is no floating environment but algorithmicx, like algorithmic, is compatible with the algorithm package. (There have been reports of difficulty defining new commands to fit with the package; unfortunately, the author is not available to comment.)
The alg package, like algorithms, offers a floating algorithm environment with all of the ensuing niceties. alg, however, can caption its floats in a variety of (natural) languages. In addition, alg unlike algorithms, makes it easy to add new constructs.
The newalg package has a somewhat similar interface to algorithms, but its output is designed to mimic the rather pleasant typesetting used in the book “Introduction to Algorithms” by Corman, Leiserson, Rivest and Stein. Unfortunately, newalg does not support a floating environment or any customisation of the output.
Bona fide use of the style of “Introduction to Algorithms” may be achieved with Cormen's own clrscode: this is the package as used in the second edition of the book.
Similarly, the style of “Combinatorial Algorithms: Generation, Enumeration and Search” is supported by the pseudocode package, written by the authors of the book. It has the common “Pascal-like” style, and has some interesting constructs for what one thinks of as Pascal blocks.
The algorithm2e package is of very long standing, and
is widely used and recommended. It loads the float package
to provide the option of floating algorithm descriptions, but you can always use
the H option of float to have the algorithm appear
“where you write it”.
The usage of the program package is a little different from
that of the other packages. It typesets programs in maths mode instead of text mode;
and linebreaks are significant. program lacks a floating environment but does
number algorithms like alg and algorithms. Customisation
and extension are not supported. Documentation of the program package
(such as it is) appears in a file program.msg in the distribution.
- quel style de sortie préférez-vous?
- dans quelle mesure avez-vous besoin d'étendre ou de modifier l'ensemble des mots-clefs prédéfinis?
- avez-vous besoin que les algorithmes flottent comme des figures ou des tableaux?
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