Re: merge function called AFTER user actions

[Derek M Jones]

Joel,

> My point here is that the current functionality seems natural and 
> necessary for all GLR parsers.  Do you disagree?

Either before or after is necessary.  Both would be helpful.
I'm not sure the term 'natural' can be applied to a human
invention.

> > Ok, so let's change its name.
> >
> > %premerge  ??
> > %initmerge ??
>
>
> This pre-merge user function would be an extra feature. I don't foresee 
> myself using it, so I really can't justify spending my own time 
> implementing it and arguing for its acceptance.

Thanks for considering it.  The implementation is trivial and
I hope the maintainers will add it to the core distribution.
I take it you will not argue against this additional functionality.

> Personally, I'd do my best to rework this logic.  Evaluate the two 
> possibilities in the two semantic actions, and then select one (or both) 
> of the values in the merge function.  That's how bison is intended to work.

I cannot find any statement about this 'intended' way of working in
the documentation.

The practical use of glr parsers is very new.  It is to be expected
that new features will be added as experience grows.

--
Derek M Jones                                  tel: +44 (0) 1252 520 667
Knowledge Software Ltd                      mailto:address@hidden
Applications Standards Conformance Testing    http://www.knosof.co.uk