current support for latex fragments was inline only, i.e. lines containing block
elements (e.g. a line starting with `* `, i.e. a headline) will not be parsed
as part of the latex fragment but the respective block element. Parsing latex
blocks at the block level should fix that. Note that in any case we don't do
any processing and just emit the raw latex (leaving the rendering to e.g. js).
WriteNodesAsString is simple enough to implement but exposing it is helpful in
the implementation of extending writers and we don't aim to keep writer a small
interface so let's expose it.
Go does not support inheritance, just composition. While composition with type
embedding (i.e. forwarding method calls to the embedded type) can replace
inheritance for most use cases this is not one of them. We really want to
overwrite methods so that method calls from inside the base writer also use the
custom methods ouf our extending writer - naive embedding does not work here
as the this in this.WriteText refers to the embedded type rather than the outer
extending type (see open recursion).
A simple solution is to make a reference of the extending type
available from the extended type and use that for nested method calls. We'll go
with that one as it does not require huge code changes. Another solution would
be to flatten the writing process and not use nested method calls - this is
what blackfriday does. Assuming the current solution works I feel it's cleaner
and keeps the ugliness of simulating inheritance with composition contained to
a small portion of the code while blackfridays approach requires all write
methods to be written in a flat style (i.e. not do nested calls to write by
being called twice with entering / leaving). The current solution becomes ugly
if we want to do multiple levels of extending but i don't expect that to be a
valid use case - if it turns out to be one we can always adapt to it
later. YAGNI.
The existing approach made it hard to extend existing writers.
With this change, replacing individual methods of a writer is possible by
embedding it.
Sharing the WriteNodes function also removes some unnecesseray duplication, so
win win.
