Re: variables in yyparse

[Hans Aberg]

At 00:39 +0100 2004/12/18, Laurence Finston wrote:
>>> The code for handling error exits
>>> from the functions and thrown exceptions has to be in the
>>> rules, though, so there's a limit to how much putting code
>>> into functions helps.
>
>> Why would C++ exceptions have to be throwed directly from the rule
>> actions, and not in functions called from these?
>
>Allocation is performed both in rule actions and in functions called from
>them.  In more recent code, I always call `new' in a `try' block and catch
>`bad_alloc'.  I'm in the process of revising old code so that I do this
>everywhere.  Where functions called from rules call `new', I wrap the calls to
>those functions in `try' blocks, catch `bad_alloc', issue an error message,
>possibly perform some clean-up, and rethrow `bad_alloc'.

I still do not see why you have to throw exceptions without the functions.
If you do not have a good memory recover, a bad_alloc usually means that the
whole program is toast. So recovery need to be somewhere where both memory
can be reclaimed and the failed code can be rerun.

  Hans Aberg