ConTeXt: Conditionally apply table footer to XHTML document

Question

Background

Style an XHTML table footer for the last row, provided a tfoot element isn't already present.

Code

Given:

\startbuffer[document]
<table>
<thead>
<tr><th>Item</th><th>Power</th><th>Usage</th><th>Cost</th></tr>
</thead>
<tbody>
<tr><td>Geothermal</td><td>1250</td><td>Electricity</td><td>5.1</td></tr> 
<tr><td>Fire Station</td><td>-9.6</td><td>Protection</td><td>0.5</td></tr> 
<tr><td>Roads</td><td>0</td><td>Transport</td><td>0.9</td></tr> 
<tr><td>Totals</td><td>129.9</td><td>n/a</td><td>19.4</td></tr> 
</tbody></table> 
\stopbuffer

\xmlregistersetup{xml:xhtml}
\startxmlsetups xml:xhtml
  \xmlsetsetup{\xmldocument}{*}{-}
  \xmlsetsetup{\xmldocument}{table|thead|tbody|tfoot|tr|th|td|caption}{xml:*}
\stopxmlsetups

\startxmlsetups xml:table
  \startembeddedxtable\xmlflush{#1}\stopembeddedxtable
\stopxmlsetups
\startxmlsetups xml:thead
  \startxtablebody[head]\xmlflush{#1}\stopxtablebody
\stopxmlsetups
\startxmlsetups xml:tbody
  \startxtablebody[body]\xmlflush{#1}\stopxtablebody
\stopxmlsetups
\startxmlsetups xml:tfoot
  \startxtablebody[foot]\xmlflush{#1}\stopxtablebody
\stopxmlsetups
\startxmlsetups xml:tr
  \startxrow\xmlflush{#1}\stopxrow
\stopxmlsetups
\startxmlsetups xml:th
  \startxcell\bold{\xmlflush{#1}}\stopxcell
\stopxmlsetups
\startxmlsetups xml:td
  \startxcell\xmlflush{#1}\stopxcell
\stopxmlsetups

\setupxtable[
  frame=off,
  topframe=on,
  bottomframe=on,
  option={stretch,width},
  split=yes,
  header=repeat,
  footer=repeat,
]

\setupxtable[head][rulethickness=1pt]
\setupxtable[body][]
\setupxtable[foot][rulethickness=1pt]

\starttext\xmlprocessbuffer{}{document}{}\stoptext

Produces:

Problem

The footer row is not recognized, which means the following style isn't applied:

\setupxtable[foot][rulethickness=1pt]

In some cases, the XHTML table includes a tfoot element; in other cases, the XHTML table does not have a tfoot. In both situations, the footer xtable setup must be applied (i.e., set the rule thickness for [foot]).

Attempts

The following nearly works, but the last row is not added to the table:

\xmlsetsetup{\xmldocument}{tr[position()<last()]}{xml:tr}
\xmlsetsetup{\xmldocument}{tr[position()=last() and ../name()='tbody']}{xml:tr:foot}
\xmlsetsetup{\xmldocument}{tr[position()=last() and ../name()='tfoot']}{xml:tr}

% ... other setups ...

\startxmlsetups xml:tr:foot
  \startxtablebody[foot]\startxrow\xmlflush{#1}\stopxrow\stopxtablebody
\stopxmlsetups

Question

How would you style the last table row when the table doesn't contain a tfoot element, such that the styling doesn't conflict when a tfoot element is present?

To clarify, in XSL the logic would resemble:

<!-- Not last row -or- is the last row but not in the footer -->
<xsl:template match="tr[not(last())] or (tr[last()] and ../tfoot)">
  \startxrow\xmlflush{#1}\stopxrow
</xsl:if>

<!-- Last row and not in the footer -->
<xsl:template match="tr[last()] and not(../tfoot)">
  \startxtablebody[foot]
    \startxrow\xmlflush{#1}\stopxrow
  \stopxtablebody
</xsl:template>

<!-- Always apply the footer when it exists -->
<xsl:template match="tfoot">
  \startxtablebody[foot]\xmlflush{#1}\stopxtablebody
</xsl:template>

ConTeXt version: 2021.03.31 18:04

Answer 1

• Remove the closing body from the xml:tbody setups.
• Introduce specific tr definitions for not last and last.
• Close the xml:tbody within the last tr.

In code:

\startxmlsetups xml:xhtml
  \xmlsetsetup{\xmldocument}{*}{-}
  \xmlsetsetup{\xmldocument}{table|thead|tbody|tfoot|th|td|caption}{xml:*}
  \xmlsetsetup{\xmldocument}{tr[position()!=last()]}{xml:tr}
  \xmlsetsetup{\xmldocument}{tr[position()=last()]}{xml:tr:last}
\stopxmlsetups

\startxmlsetups xml:tbody
  \startxtablebody[body]
    \xmlflush{#1}
\stopxmlsetups

\startxmlsetups xml:tr:last
  \stopxtablebody
  \startxtablebody[foot]
  \startxrow\xmlflush{#1}\stopxrow
  \stopxtablebody
\stopxmlsetups

This is a bit brittle.