Re: [pdf-devel] Error management in type 4 functions

[David Vazquez]

> Would be useful to return more detailed information: it would be
> really difficult to fix a buggy function facing something like
> "Internal error". But it would be quite difficult to do it in a
> generic way.
>
> What about adding a new specific `pdf_fp_func_4_eval' function? It
> would break the generic function application schema, but we can always
> expand the API to ask a function its type.
>
> What do you think?

I think we could use an extra union structure argument for this. We could
use the return value to specify generic errors listed previously, and the
extra argument in order to get more detailed info. Anyway, as far I know,
other type functions should not fail, right?

I read the operands from PostScript Reference Language. We should report
following errors:
   - stackoverflow
   - stackunderflow
   - typecheck
   - undefinedresult
   - rangecheck

Finally we could include what operator failed, offset in the code, even a
copy of the stack if this was useful for debugging.