Re: [GLISS] - alternative viewpoint

[David Kastrup]

Janek Warchoł <address@hidden> writes:

> On Sat, Sep 15, 2012 at 11:35 AM, David Kastrup <address@hidden> wrote:
>>
>> You mean, currently we basically see the default error message from the
>> parser generator.  Improving this involves basically accepting errors in
>> input and acting on them by putting out hand-tailored messages.
>>
>> 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 am working towards recognizing
>> elements of the syntax in isolation, and then pasting them together.
>> The "pasting together" is then done outside of the immediate control of
>> the parser and can trigger independent error messages based on the
>> assumption that at least the elements used for combining were, by
>> themselves, recognized correctly.  Those error messages can be more
>> specific and helpful than the boilerplate parse errors from the parser
>> generator.
>
> Hmm, this sounds complicated.  Do you mean that implementing more
> informative ("custom") error messages with current parser will wreak
> havoc, but if we simplify the parser first, it would be possible to do
> this in a sane way?

No.  I don't mean "wreak havoc" but rather "will be in the way while I
am still reworking the parser internals".  It's like putting up tapestry
and setting up furniture before doing the plumbing.

-- 
David Kastrup