Hans Aberg wrote -- > The apparent reason this gives "improved syntax checking" is due to a bug > in LaTeX!: > > When nesting environments, there are more than environment to keep track > of for the error checking, which LaTeX does not do. This is an area where we have some ideas but it is necessary to think clearly about what is needed. Here are some desirable features of such a specification: -- provide a straightforward means of extending the available document-level environments (and commands), with clearly defined rules for what is allowed; -- distinguish (to both humans and software) clearly between such extensions (where the detailed syntax is very flexible) and an inner-level which has a rigorously defined syntax that is extensible only in more complex ways within (something like) package files; -- hence fix such "bugs". If anyone is intersted in putting substantial work into implementing such ideas, please contact Them. This would involve some major programming using the LaTeX3 PL (and of course developing it) and implementing in it any low-level structures needed. chris