This function can be used to sanitize reference labels so that
they do not contain any of the illegal characters \#[]",{}%()|= .
Currently only Links have their labels sanitized, because they
are the only Elements that use passed labels.
We previously took the old relationship names of the headers and footer in
secptr. That led to collisions. We now make a map of availabl names in the
relationships file, and then rename in secptr.
Graphics in `\section`/`\subsection` etc titles need to be `\protect`ed.
This adds a state value and manually turns it on before every invocation
of `sectionHeader` and manually turns it off after. Using a writer value
and applying `local` would probably be cleaner, but this fits with the
current style.
When we encounter one of the polyglot header styles, we want to remove
that from the par styles after we convert to a header. To do that, we
have to keep track of the style name, and remove it appropriately.
We're just keeping a list of header formats that different languages use
as their default styles. At the moment, we have English, German, Danish,
and French. We can continue to add to this.
This is simpler than parsing the styles file, and perhaps less
error-prone, since there seems to be some variations, even within a
language, of how a style file will define headers.
When users number their headers, Word understands that as a single item
enumerated list. We make the assumption that such a list is, in fact, a header.
Currently, pandoc has hard-coded the following in order to make tight lists in
LaTeX:
```hs
text "\\itemsep1pt\\parskip0pt\\parsep0pt"
```
Which is fine, but does not allow customizations. For example, the `memoir`
class already has a `\tightlist` declaration for this purpose:
```tex
\newcommand{\tightlist}{%
\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}
```
I'm proposing to use a similar solution:
```diff
@@ In Writers/LaTeX.hs:
-then text "\\itemsep1pt\\parskip0pt\\parsep0pt"
+then text "\\tightlist"
@@ In templates/default.latex:
+\newcommand{\tightlist}{%
+ \setlength{\itemsep}{1pt}\setlength{\parskip}{0pt}\setlength{\parsep}{0pt}}
```
This allows us to customize the tightness to our needs.
Backward Compatibility
If a person is using a custom LaTeX template (not based upon the `memoir`
class), the `\tightlist` declaration must be added.
