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2  Style files

LATEX style files are files that are not intended to produce output, but define document layout parameters, commands, environments, etc.

2.1  Standard base styles

The base style of a LATEX document is the argument to the \documentclass command (\documentstyle in old style). Normally, the base style of a document defines the structure and appearance of the whole document.

HEVEA knows about two LATEX base styles, article and book. Additionally, the report base style is recognized and considered equivalent to book and the seminar base style for making slides is recognized and implemented by small additions on the article style.

Base style style is implemented by an HEVEA specific style file whose name must be style.hva. More precisely, HEVEA interprets \documentclass{style} by attempting to load the file style.hva (see section C.1.1 on where HEVEA searches for files). Thus, at the moment, HEVEA distribution includes the files, article.hva, book.hva, etc.

2.2  Other base styles

Documents whose base style is not recognized by HEVEA can be processed when the unknown base style is a derivation of a recognized base style.

Let us assume that mydoc.tex uses an exotic base style such as acmconf. Then, typing hevea mydoc.tex will yield an error, since HEVEA cannot find the acmconf.hva file:
# hevea.opt mydoc.tex
mydoc.tex:1: Warning: Cannot find file: acmconf.hva
mydoc.tex:1: Error while reading LaTeX: No base style
Adios
This situation is avoided by invoking HEVEA with the known base style file article.hva as an extra argument:
# hevea article.hva mydoc.tex
The extra argument instructs HEVEA to load its article.hva style file before processing mydoc.tex It will then ignore the document base style specified by \documentclass (or \documentstyle).

Observe that the fix above works because the acmconf and article base styles look the same to the document (i.e., they define the same macros). More generally, most base styles that are neither article nor book are in fact variations on either two of them. However, such styles usually provides extra macros. If users documents use these macros, then users should also instruct HEVEA about them (see section 4.1).

Finally, it is important to notice that renaming a base style file style.cls into style.hva will not work in general. As a matter of fact, base style files are TeX and not LATEX source and HEVEA will almost surely fail on TeX-ish input.

2.3  Other style files

A LATEX document usually loads additional style files (using \input or \usepackage, or by giving optional arguments to \documentstyle). HEVEA simply ignores \usepackage and optional arguments to \documentstyle, but it attempts to load a file given as argument to \input. (You can see what files HEVEA loads or attempts to load by using the -v option.)

A simple situation is when HEVEA is not happy with just a few macros in a style file. As it is often the case, assume that the document mydoc.tex has a \input{macros.tex} instruction in its preamble, where macros.tex gathers custom definitions. Hopefully, only a few macros give rise to trouble: macros that performs fine typesetting or TeXish macros. Such macros need to be rewritten, using basic LATEX constructs (section 4 gives examples of macro-rewriting). The new definitions are best collected in a style file, macros.hva for instance. Then, mydoc.tex is to be translated by issuing the command:
# hevea macros.hva mydoc.tex
The file macros.hva is processed before mydoc.tex (and thus before macros.tex). As a consequence, the macro definitions in mymacros.tex override the ones in macros.tex, since the latter are made using \newcommand or \def (section B.8.1 explains how HEVEA handle macro definitions and redefinitions).

Another situation is when HEVEA fails to process a whole style file. Usually, this means that HEVEA crashes on that style file. Then, you should also instruct HEVEA not to load the faulty file, by issuing the command:
# hevea macros.hva -e macros.tex mydoc.tex
Of course, macros.hva must now contain replacements for all the useful macros of macro.tex. Note that another solution to instruct LATEX to load a file and HEVEA not to load it is to use \usepackage or optional arguments to \documentstyle, which HEVEA ignores.

2.4  The hevea.hva file

The hevea.hva resides in HEVEA library and is loaded before any other file specified by users. It contains the definitions of most LATEX core commands and environments, HEVEA can be customized by redefining these constructs using \renewcommand or \renewenvironment (see section 3.5).


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