[tex4ht] [bug #477] Support for new LaTeX hook management

[Ulrike Fischer]

>> Well I know that rewriting such patches is hard, but this \document
>> redefinition looks very fragile. Sadly I can't make a concrete suggestion
>> how to change it as I have no idea what all the code is doing and what
>> should come before and after other things.

> Yes, it will be fragile, unfortunately. This is the code that loads
> .4ht files and then calls the original \document:

[...]

> It checks if the .cfg file was required, if it wasn't, it will call
> \Preamble, \begin{document}, and \EndPreamble. 

[...]

I know, I mean I checked the code and see the details. What I do not 
understand is the overall picture. 

So if you do a step back and remove in your mind all this 
redefinitions and assume a fresh, unchanged \document command. 

Which tasks do you have to do when you encounter \begin{document} and
which when you encounter \document? 
Which of them can you do with the normal hooks? 
Which of them can't you do and why not? What fails?

Ulrike