Re: [GLISS] - alternative viewpoint

[David Kastrup]

Werner LEMBERG <address@hidden> writes:

>> Currently, the parser is still undergoing significant restructuring
>> work in major areas and mechanisms.  That work entails a lot of time
>> spent on ironing out parser conflicts where some input would
>> correspond to multiple and diverging interpretations according to
>> the current syntax.  It is significant work ironing out those
>> conflicts.  Adding additional rules for erroneous input means more
>> potential for conflict, so it would make the ongoing work even
>> harder.
>
> I suggest that the possibility of improved error messages should be
> taken into account while doing design decisions.

Well, the "accumulate expressions that make sense on their own" approach
means that the accumulation can provide useful error messages.  It
basically leads to an "accept and complain" approach in the parser
regarding the actual syntax ("accept" does not mean that anything useful
is or can be done, just that the parser does not get lost altogether).

The disadvantage is that the syntax description of LilyPond (in the
appendices of the notational manual) becomes less and less useful for
figuring out what a syntactically correct LilyPond program is supposed
to look like.

At the moment, not many "design decisions" actually are happening in
parser work: most of the work focuses on creating a more coherent and
logical framework able to reflect the existing design while being better
extensible and manageable.

-- 
David Kastrup