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"http://www.w3.org/TR/REC-html40/loose.dtd">
Extra Features
This section describes HEVEA functionalities that extends on plain LATEX,
as defined in [LATEX].
Most of the features described here are performed by default.
Loading the mathaccents.hva style files enables
default typesetting of the math
accents commands
(\hat, \tilde,...), see Section B.7.4.
Normally, HEVEA does not recognize constructs that are specific to
TeX.
However, some of the internal commands of HEVEA are homonymous to
TeX macros, in order to enhance compatibility.
Note that full compatibility with TeX is not guaranteed.
| B.16.2.1 |
À la TeX macros definitions |
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The \def construct for defining commands is supported.
It is important to
notice that HEVEA semantics for \def
follows TeX semantics.
That is, defining a command that already
exists with \def succeeds.
This is an important change with respect to previous versions of
HEVEA, where \def had the same semantics as
\newcommand.
Delimiting characters in command definition are supported.
Consider the following example from the TeX Book:
\def\Look{\textsc{Look}}
\def\x{\textsc{x}}
\def\cs AB#1#2C$#3\$ {#3{ab#1}#1 c\x #2}
\cs AB {\Look}{}C${And \$}{look}\$ 5.
It yields:
And $lookabLookLook cx5.
Please note that delimiting characters are supported as far as I
could, problems are likely with delimiting characters which include
spaces or command names, in particular the command name \{.
One can include \{ in a command argument by using the grouping
characters {... }:
\def\frenchquote(#1){«~\emph{#1}~» (in French)}
He said \frenchquote(Alors cette accolade ouvrante {``\{''}~?).
Yields:
He said « Alors cette accolade ouvrante ``{'' ? » (in French).
Another source of incompatibilty with TeX is that substitution of
macros parameters is not performed at the same moment by HEVEA and
TeX.
However, things should go smoothly at the first level of macro
expansion, that is when the delimiters
appear in source code at the same level as the macro that is to
parse them.
For instance, the following source will give different results in
LATEX and in HEVEA:
\def\cs#1A{``#1''}
\def\othercs#1{\cs#1A}
\othercs{coucouA}
LATEX output is ``coucou''A, while HEVEA output is ``coucouA''.
Here is HEVEA output:
``coucouA''
Please note that in most situations this discrepancy will make
HEVEA crash.
| B.16.2.2 |
The \let construct |
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HEVEA also processes a
limited version of \let:
\let macro-name1 = macro-name2
The effect is to bind macro-name1 to whatever macro-name2
is bound to at the time \let is processed. This construct may
prove very useful in situations where
one whishes to slightly modify basic commands.
See sections 9.3 and B.2 for examples of using
\let in such a situation.
| B.16.2.3 |
The \global construct |
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It is possible to escape scope and to make global definitions
and bindings by using the TeX construct \global.
The \global construct is significant before
\def and \let constructs.
Also note that \gdef is equivalent to \global\def.
| B.16.2.4 |
TeX Conditional Macros |
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The \newif\ifname, where name is made of letters
only, creates three macros:
\ifname, \nametrue and
\namefalse.
The latter two set the name condition to true and
false, respectively.
The \ifname command tests the condition name:
\ifname
text1
\else
text2
\fi
Text text1 is processed when name is
true, otherwise text2 is processed.
If text2 is empty, then the \else keyword can be
omitted.
Note that HEVEA also implements LATEX ifthen package
and that TeX simple conditional macros are fully compatible with
LATEX boolean registers. More precisely,
we have the following correspondences:
| TeX |
LATEX |
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\newifname |
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\newboolean{name} |
\nametrue |
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\setboolean{name}{true} |
\namefalse |
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\setboolean{name}{false} |
\ifname text1\else
text2\fi |
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\ifthenelse{\boolean{name}}{text1}{text2} |
| B.16.2.5 |
Other TeX Macros |
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HEVEA implements the macros \unskip and \endinput.
It also supports the \csname... \endcsname
construct.
| B.16.3 |
Command Definition inside Command Definition |
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If one strictly follows the LATEX manual, only commands with no
arguments can be defined inside other commands.
Parameters (i.e., #n) occurring inside command bodies
refer to the outer definition, even when they appear in nested
command definitions.
That is, the following source:
\newcommand{\outercom}[1]{\newcommand{\insidecom}{#1}\insidecom}
\outercom{outer}
yields this output:
outer
Nevertheless, nested commands with arguments are allowed.
Standard parameters #n still refer to the outer
definition, while nested parameters ##n refer to the
inner definition.
That is, the source:
\newcommand{\outercom}[1]{\newcommand{\insidecom}[1]{##1}\insidecom{inner}}
\outercom{outer}
yields this output:
inner
Date and time support is not enabled by default, for portability and
simplicity reasons.
However, HEVEA source distribution includes a simple (sh)
shell script
xxdate.exe that activates date and time support.
The hevea command, should be invoked as :
# hevea -exec xxdate.exe ...
This will execute the script xxdate.exe, whose output is then
read by HEVEA.
As a consequence, standard TeX counters \year,
\month, \day and
\time are defined and
LATEX command \today works properly.
Additionnally the following counters and commands are defined :
| |
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| Counter weekday |
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day of week, 0...6
(e.g. 2) |
| Counter Hour |
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hour, 00...11
(e.g. 11) |
| Counter hour |
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hour, 00...23 (e.g. 11) |
| Counter minute |
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minute, 00...59
(e.g. 35) |
| Counter second |
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second, 00...611
(e.g. 57) |
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Command \ampm |
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AM or PM
(e.g. AM) |
Command \timezone |
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Time zone
(e.g. CEST) |
Command \heveadate |
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Output of the ``date'' Unix
command, (e.g. mar mai 21 11:35:57 CEST 2002) |
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Note that I choosed to add an extra option (and not an extra
``\@exec'' primitive) for security reasons. You certainly do
not want to enable HEVEA to execute silently an arbitrary program
without being conscious of that fact.
Moreover, the hevea program does not execute
xxdate.exe by default since it is difficult to write such
a script in a portable manner.
Windows users should enjoy the same features with the version of
xxdate.exe included in the Win32 distribution.
| B.16.5 |
Fancy sectioning commands |
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Loading the fancysection.hva file will radically change the
style of sectionnal units headers: they appear over a green
backgroud, the backgrould color saturation decreases as the sectioning
commands themselves do (this is the style of this manual).
Additionnaly, the document background color is white.
The fancysection.hva file is intended to be loaded after
the document base style. Thus, to use fancy section style in
doc.tex whose base style is article
you should issue the command:
# hevea article.hva fancysection.hva doc.tex
You can also make a doc.hva file that contains the two lines:
\input{article.hva}
\input{fancysection.hva}
And then launch hevea as:
# hevea doc.hva doc.tex
Sectioning command background colors can be changed by
redefining the corresponding colors (part, chapter,
section,...).
For instance, you get various mixes of red and orange by:
\input{article.hva}
\input{fancysection.hva}
\definecolor{part}{named}{BrickRed}
\definecolor{section}{named}{RedOrange}
\definecolor{subsection}{named}{BurntOrange}
(See section B.14.2 for details on the named
color model that is used above.)
Another choice is issuing the command
\colorsection{hue}, where
hue is a hue value to be interpreted in the HSV model.
For instance,
\input{article.hva}
\input{fancysection.hva}
\colorsections{20}
will yield sectionnal headers on a red-orange background.
| B.16.6 |
HEVEA as a Back-End for VideoC |
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HEVEA is one of the back-ends of the VideoC system for producing
educational CDROM to teach programming languages.
VideoC author is Christian Queinnec and the documentation is available
at:
VideoC translates LATEX source into a variety of formats, including
HTML. VideoC source may contain some special constructs for
typesetting source code or to annotate text in sophisticated ways.
HEVEA internal engine implements some of the core constructs needed
by VideoC. The rest of VideoC constructs are implemented by
the .hva files from VideoC distribution.
- 1
- According to
date man page.
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