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"http://www.w3.org/TR/REC-html40/loose.dtd">
The array and tabularx
Packages
| B.17.2 |
The array and tabularx
Packages |
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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
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m{width} |
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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. |
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b{width} |
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Equivalent to the p column specification, except that the entries
are bottom-aligned vertically. |
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>{decl} |
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Can be used before l, c, r,
p{...}, m{...} or
b{...}.
It inserts decl in front of the entries in the corresponding
column. |
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<{decl} |
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Can be used after l, c, r,
p{...}, m{...} or
b{...}.
It inserts decl after entries in the corresponding
column. |
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!{decl} |
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Equivalent to @{decl} |
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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:
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| one |
two |
three |
four |
| five |
six |
seven |
eight |
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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.
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