errors and warnings

Hi,

There are some decisions about errors and warnings that can be taken.

1) Don't write the files on error ?

makeinfo won't write the files if an error occur, unless --force is given.
Should we try to mimic that (I am not certain we can do the same as some
errors appear very late, and we have allready begun writing to the files, but
at least we can do that for errors appearing in document structuring or
macros expansion).

My personnal opinion is to keep the current behaviour, always write down the 
files.

2) Have a clear rule for warnings and errors ?

Currently it is an error if a language spec doesn't exist. I think it is 
not right. And it is a warning when the Top node is redefined. And sometimes
it is a warning when the texinfo isn't correct, sometime it is an error.
Should we have formal rules for deciding what is an error and what is a 
warning or let the developpers try to do their best ?

I think that this isn't purely academic, as it could be possible to do 
different things if this is an error or a warning (abort on error, use
--no-warn to avoid printing of warnings...).

Pat