Everything hsc knows about html, it retrieves from a file named hsc.prefs at startup. This file contains information about all tags, entities and icon-entites. Additionally, some special attributes are set up there also.
The main advantage of this concept is that it's rather
easy to add new syntax elements. For this task, the hsc-tags
<$deftag>, <$defent> and <$deficon> can be used. These
are described in the section about special tags.
The hsc.prefs coming with this distribution should support most elements needed for everyday use. This includes full html-2.0-support, tables, figures, client-side image-maps and several elements only used by special browsers.
A few weeks ago, something terrible has happended: html-0.32 has been released. From my point of view, this nothing more than the proof that those browser-developers, who clutter their software with loads of jerk-tags are too tumb to write a DTD (Document Type Definition) themselves and that the only reason that w3c still exists is that someone has to write those DTDs to pretend that there is a concept behind html.
Altough the DTD is out since 7-May-1996, there are less other documents available about html-0.32. Therefor, the current hsc.prefs is in a bit chaotic state and a mixture of html-2.0, html-3.0-draft and html-0.32. Anyway, this shouldn't cause real problems for you, expept some maybe wrong jerk-related warnings.
Currently, there's also a disadvantage: reading hsc.prefs every time on startup uses an awful lot of time. Usually, processing your main data takes shorter than reading the preferences. You can reduce this time, if you create your own hsc.prefs with all tags and entites you don't need removed. But I recommend to avoid this because you might have to edit your preferences again with the next update of hsc, if any new features have been added.
You also can't use the DTDs. This is because DTDs don't contain several information needed by hsc, for example entities are not defined within he DTD. Also several features of hsc like evaluation of image-sizes or stripping of external URIs can only be controlled with hsc.prefs.