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B.17  Implemented Packages

HEVEA distribution includes “.hva” packages that are implementations of LATEX packages. Packages described in the “Blue Book” (makeidx, ifthen, graphics —and graphicx!—, color, alltt) are provided. Additionnaly, quite a few extra packages are provided. I provide no full documentation for these packages, users should refer to the first pages of the package documentation, which can usually be found in the book [LATEX-bis], in your local LATEX installation or in a TeX CTAN-archive.

At the moment, package options are ignored, except for the babel package, where it is essential.

B.17.1  AMS compatibility

HEVEA amsmath package defines some of the constructs of the amsmath package. At the moment, supported constructs are the cases environment and matrix environments [LATEX-bis, Section 8.4], the environments for multi-line displayed equations (gather, split,...) [LATEX-bis, Section 8.5] and the \numberwithin command [LATEX-bis, Section 8.6.2].

B.17.2  The array and tabularx Packages

The array package is described in [LATEX-bis, Section 5.3] and in the local documentation of modern LATEX installations. It is a compatible extension of LATEX arrays (see B.10.2). Basically, it provides new column specifications and a \newcolumntype construct for user-defined column specifications. Table 1 gives a summary of the new column specifications and of how HEVEA implements them.



Table 1: Column specifications from the array package


m{width}    Equivalent to the p column specification (the width argument is ignored, entries are typeset in paragraph mode with paragraph breaks being reduced to a single line break), except that the entries are centered vertically.
b{width}    Equivalent to the p column specification, except that the entries are bottom-aligned vertically.
>{decl}    Can be used before l, c, r, p{...}, m{...} or b{...}. It inserts decl in front of the entries in the corresponding column.
<{decl}    Can be used after l, c, r, p{...}, m{...} or b{...}. It inserts decl after entries in the corresponding column.
!{decl}    Equivalent to @{decl}

Note that centered, top-aligned or bottom-aligned in the vertical direction, do not have exactly the same meaning in LATEX and in HTML. However, the aspect is the same when all columns agree w.r.t. vertical alignment. Ordinary column types (c, l and r) do not specify vertical alignment, which therefore becomes browser dependent.

The >{decl} and <{decl} constructs permit the encoding of TEX \cases macro as follows:
\def\cases#1{\left\{\begin{array}{l>{$}l<{$}}#1\end{array}\right.}
(This is an excerpt of the latexcommon.hva file.)

New column specifications are defined by the \newcolumntype construct:
  \newcolumntype{col}[narg]{body}
Where col is one letter, the optional narg is a number (defaults to 0), and body is built up with valid column specifications and macro-argument references (#int). Examples are:
\newcolumntype{C}{>{\bf}c}
\newcolumntype{E}[1]{*{#1}{c}}
\begin{tabular}{CE{3}}\hline
one & two & three & four \\
five & six & seven & eight \\ \hline
\end{tabular}
The column specification C means that entries will be typeset centered and using bold font, while the column specifications E{num} stands for num centered columns. We get:

one two three four
five six seven eight

HEVEA implements column specifications with commands defined in the \newcommand style. Thus, they have the same behavior as regards double definition, which is not performed and induces a warning message. Thus, a column specification that is first defined in a macro.hva specific file, overrides the document definition.

The tabularx package [LATEX-bis, Section 5.3.5] provides a new tabular environment tabularx and a new column type X. HEVEA makes the former equivalent to tabular and the latter equivalent to p{ignored}. By contrast with the subtle array formatting that the tabularx package performs, this may seem a crude implementation. However, rendering is usually correct, although different.

More generally and from the HTML point of view such sophisticated formatting is browser job in the first place. However, the HTML definition allows suggested widths or heights for table entries and table themselves. From HEVEA point of view, drawing the border line between what can be specified and what can be left to the browser is not obvious at all. At the moment HEVEA choice is not to specify too much (in particular, all length arguments, either to column specifications or to the arrays themselves, are ignored). As a consequence, the final, browser viewed, aspect of arrays will usually be different from their printed aspect.

B.17.3  The calc Package

LATEX source and documentation.

This package enables using traditional, infix, notation for arithmetic operations inside the num argument to the \setcounter{name}{num} and \addtocounter{name}{num} constructs (see [LATEX-bis, Section A.4])

The calc package provides a similar extension of the syntax of the len argument to the \setlength and \addtolength constructs. HEVEA does not implement this extension, since it does not implement length registers in the first place.

B.17.4  The comment Package

LATEX source.

The implementation for this package provides two commands, \excludecomment and \includecomment, for (re-)defining new environments that ignore their content or that do nothing. The comment environment is also defined as an environment of the first kind.

B.17.5  Multiple Indexes with the index and multind package

HEVEA supports several simultaneous indexes, following the scheme of the index package, which is present in modern LATEX distributions. This scheme is backward compatible with the standard indexing scheme of LATEX.

Support is not complete, but the most useful commands are available. More precisely, HEVEA knows the following commands:
\newindex{tag}{ext}{ignored}{indexname}
Declare an index. The first argument tag is a tag to select this index in other commands; ext is the extension of the index information file generated by LATEX (e.g., idx); ignored is ignored by HEVEA; and indexname is the title of the index. If given the idx option. HEVEA attempts to read file mydoc.ext. There also exists a \renewindex commands that takes the same arguments and that can be used to redefine previously declared indexes.
\makeindex
Perform \newindex{default}{idx}{ind}{Index}. z
\index[tag]{arg}
Act as the LATEX \index command except that the information extracted from arg goes to the tag index. The tag argument defaults to default, thereby yielding standard LATEX behavior for the \index command without an optional argument. There also exists a stared-variant \index* that Additionally typesets arg.
\printindex[tag]
Compute, format and output index whose tag is tag. The tag argument defaults to default.

B.17.6  Multiple Bibliographies with the multibib package

HEVEA provides a slighty incomplete implementation of the multibib package. The one non-implemented feature is the simultaneous definition of more than one bibliography. That is one cannot invoke \newcites as follows :
\newcites{suf1, suf2}{Title1, Title2}
Instead, one should perform to calls to the \newcites command :
\newcites{suf1}{Title1}
\newcites{suf2}{Title2}

B.17.7  Support for babel

B.17.7.1  Basics

HEVEA offers support for the LATEX package babel. When it reads the command
  \usepackage[lang-list]{babel}
it loads babel.hva, and sends it the saved lang-list. The file babel.hva then looks at each language (say x) in it, and loads x.hva, which offers support for the language x. As in LATEX, the last language in the list is selected as default. As an example the command
\usepackage[english,french,german]{babel}
would load babel.hva, then the files english.hva,french.hva,german.hva containing the respective definitions, and finally activate the definitions in greman.hva and sets the current language to german.

B.17.7.2  Commands and Languages

The following babel commands for changing and querying the language work as in LATEX :
  1. \selectlanguage : to change the language
  2. \iflanguage : to branch after comparing with current language
The language specific details are described in the corresponding .hva file, just as in the .sty file for LATEX. Users need to supply this file for their language, or modify/check the files if thay are already supplied with the distribution. The list of languages is given below.

american austrian brazil catalan
check croatian danish dutch
english esperanto finnish french
galician german italian magyar
norsk nynorsk polish portuges
romanian russian slovak slovene
spanish swedish turkish  


B.17.7.3  Writing hva Files

The languages for which .hva files are available with the distribution are english, french, german, austrian and czech. These may need to be modified as not all accents and hyphenation techniques are supported.

They can be written/modified as simple TEX files (see the section  B.16.2.1 on writing TEX macros for details). As an example, one may also take a look at the file french.hva, which describes the details for french.

Note how all definitions are inside the definition for \french@babel, which is the command that \selectlanguage{french} would call. Similar commands need to be provided (i.e. \x@babel in \x.hva for language x).

Some definitions may involve specifying unicode encodings. The map from characters to unicode can be found at http://www.unicode.org/charts/ . Most language specific unicode characters can be found in the first few files.

B.17.8  Support for Math Package amssymb

HEVEA provides support for the amssymb symbols using unicode character encodings. However, a few symbols did not have any encoding yet (e.g. \varsubsetneqq, ⫋), and were approximated to their nearest kin (e.g. \subsetneqq, ⫋ in this case).

There were yet others which had unicode encodings, but not supported by current versions of some browsers (e.g. \ltimes, ⋉). A similar fate awaited them. However, as it is hoped that sooner rather than later, browsers will support these entities, a command-line option `-goodbrowser' can be used to activate them. Users are urget to try out the test file amssymb-test.html, for details on which symbols are supported by their browsers, and whether or not they should use the -goodbrowser option.

B.17.9  The url package

LATEX source.

This package in fact provides a enhanced \verb command that can appear inside other command arguments. This command is named “\url”, but it can be used for any verbatim text, including DOS-like path names. Hence, one can insert urls in one's document without worrying about LATEX active characters :
This is a complicated url: \url{http://foo.com/~user#label%coucou}.
which gets typeset as: “This is a complicated url: http://foo.com/~user#label%coucou.”

Main use for the \url command is to specify urls as arguments to HEVEA commands for hyperlinks (see section 8.1.1) :
\hevea{} home page is
\ahrefurl{\url{http://pauillac.inria.fr/~maranget/hevea/}}
It yields : “HEVEA home page is http://pauillac.inria.fr/~maranget/hevea/”.

However the \url command is fragile, as a consequence it cannot be used inside \footahref first argument (This is a LATEX problem, not an HEVEA one). The url package solves this problem by providing the \urldef command for defining commands whose body is typeset by using \url:
\urldef{\heveahome}{\url}{http://pauillac.inria.fr/~maranget/hevea/}
Such a source defines the robust command \heveahome as the intended url. Hence the following source works as expected :
Have a look at \footurl{\heveahome}{\hevea{} home page}
It yields: “Have a look at HEVEA home page”.

Using \url inside command definitions with a #i argument is a bad idea, since it gives “verbatim” a rather random meaning. Unfortunately, in some situations (e.g, no %, no #), it may work in LATEX. By contrast, it does not work in HEVEA. In such situations, \urldef should be used.

HEVEA implementation is somehow compatible at the “programming level”. Thus, users can define new commands whose argument is understood verbatim. The urlhref.hva style file from the distribution takes advantage of this to define the \url command, so that it both typesets an url and inserts a link to it.
\input{urlhref.hva}
Have a look at \url{http://pauillac.inria.fr/~maranget/hevea/}
It yields “Have a look at http://pauillac.inria.fr/~maranget/hevea/”. The urlhref.hva style file (which is an HEVEA style file and not a LATEX style file) can be adequate for bibliographic references, which often use \url for its typesetting power. Of course, loading urlhref.hva only makes sense when all arguments to \url are urls...

B.17.10  Verbatim Text : the moreverb and verbatim Packages

These two packages provide new commands and environments for processing verbatim text. I recommend using moreverb rather than verbatim, since HEVEA implementation is more advanced for the former package.

B.17.11  Typesetting Computer Languages: the listings Package

I strongly recommend using the listings package. Learning the user interface requires a little effort, but it is worth it.

HEVEA features a quite compatible implementation, please refer to the original package documentation. Do not hesitate to report discrepancies. Note that HEVEA does not produce very compact HTML in case you use this package. This can be cured, at some price in runtime cost, by giving hevea the command line option “-O” (see Section C.1.1.4).

B.17.12  The mathpartir package

The mathpartir package, authored by D. Rémy, essentially provides two features:
  1. An environment mathpar for typesetting a sequence of math formulas in mixed horizontal and vertical mode. The environment selects the best arrangement according to the line width, exactly as paragraph mode does for words.
  2. A command \inferrule (and its starred variant) for typsetting inferences rules.
We give a short description, focussing on HEVEA-related details. Users are encouraged to refer to the original documentation of the package. In the following, comments on rule typesetting apply to HEVEA output and not to LATEX output.

B.17.12.1  The mathpar environment

In its LATEX version, the mathpar environment is a “paragraph mode for formulas”. It allows to typeset long list of formulas putting as many as possible on the same line:
\begin{mathpar} A-Formula \and Longer-Formula \and And \and The-Last-One \end{mathpar}
        
AFormula      LongerFormula      And      TheLastOne
In the example above, formulas are separated with \and. The LATEX implementation also changes the meaning of paragraph breaks (either explicit as a \par command or implicit as a blank line) to act as \and. It also redefines the command \\ as an explicit line-break in the flow of formulas.

The HEVEA version is simplistic: \and separators always produce horizontal space, while \\ always produce line-breaks. However, when prefixed by \hva the meaning of explicit speparators is inversed: that is, \hva\and produces a line-break, while \hva\\ produces horizontal space. Hence, we can typeset the previous example on two lines:
\begin{mathpar} A-Formula \and Longer-Formula \hva\and And \and The-Last-One \end{mathpar}
        
AFormula      LongerFormula
And      TheLastOne


It is to be noticed that the LATEX version of the package defines \hva as a no-op, so as to allow explicit instructions given to HEVEA not to impact on the automatic typesetting performed by LATEX.

B.17.12.2  The inferrule macro

The \inferrule macro is designed to typeset inference rules. It should only be used in math mode (or display math mode). It takes three arguments, the first being optional, specifying the label, premises, and conclusions respectively. The premises and the conclusions are both lists of formulas, and are separated by \\.

A simple example of its use is
\inferrule
  [label]
  {one \\ two \\ three \\ or \\ more \\ premisses}
  {and \\ any \\ number \\ of \\ conclusions \\ as \\ well}
which gives the following rendering:
label
one           two           three           or           more           premisses
and           any           number           of           conclusions           as           well
Again, HEVEA is simplistic. Where LATEX performs actual typesetting, interpreting \\ as horizontal or vertical breaks, HEVEA always interpret \\ as an horizontal break. In fact HEVEA interpret all separators (\\, \and) as horizontal breaks, when they appear in the arguments of the \inferrule command. Nethertheless prefixing separators with \hva yields vertical breaks:
\inferrule {aa \hva\\ bb} {dd \\ ee \\ ff}
        
aa
bb
dd           ee           ff

The color of the horizontal rule that separates the premises and conclusions can be changed by redefining the command \mpr@hhline@color. This color must be specified as a low-level color (cf. Section B.14.2.2).

B.17.12.3  Options

By default, lines are centerred in inference rules. However, this can be changed either by using \mprset{flushleft} or \mprset{center}, as shown below.
$$\mprset{flushleft} \inferrule {a \\ bbb \hva\\ ccc \\ dddd} {e \\ ff \hva\\ gg} $$
        
a           bbb
ccc           dddd
e           ff
gg

B.17.12.4  Derivation trees

The mathpartir package provides a starred variant \inferrule*. In LATEX, the boxes produced by \inferrule and \inferrule* differ as regards their baseline, the second being well adapted to derivation trees. All this is irrelevant to HEVEA, but \inferrule* remains of interest because of its interface: the optional argument to the \inferrule* command is a list of key=value pairs in the style of keyval. This makes the variant command much more flexible.
key Effect for value v
before Execute v before typesetting the rule. Useful for instance to change the maximal width of the rule.
left Put a label v on the left of the rule
Left Idem.
right As left, but on the right of the rule.
Right As Left, but on the right of the rule.
lab Put a label v above the inference rule, in the style of \inferrule.
Lab Idem.
vdots Raise the rule by v and insert vertical dots, the length argument is translated to a number of line-skips.
Additionally, the value-less key center centers premises and conclusions (this is the default), while flushleft commands left aligment of premises and conclusions (as \mprset{flushleft} does). Other keys defined by the LATEX package exist and are parsed, but they perform no operation.

As an example, the code
\begin{mathpar} \inferrule* [Left=Foo] {\inferrule* [Right=Bar,width=8em, leftskip=2em,rightskip=2em,vdots=1.5em] {a \and a \and bb \hva\\ cc \and dd} {ee} \and ff \and gg} {hh} \hva\and \inferrule* [lab=XX]{uu \and vv}{ww} \end{mathpar}
produces the following output:
Foo 
a           a           bb  Bar
cc           dd  
ee  

          ff           gg
  hh
XX
uu           vv
ww


B.17.13  Experimental Implementations

The fancyverb and colortbl packages are partly implemented.


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