Re: Context.Grob considered as symbol list

[David Kastrup]

Werner LEMBERG <address@hidden> writes:

>>> On the other hand: Wouldn't it be possible to make LilyPond simply
>>> walk over all possible combinations to find out whether, say,
>>>
>>>   foo.bar
>>>
>>> is a context followed by a property, or a property followed by a
>>> sub-property, etc.?
>>
>> Technically impossible.  At the time an \override is parsed, the
>> valid set of contexts has not been established.
>
> OK.  And the interpretation of the just parsed data (this is, checking
> the validity of contexts, properties, etc.) can't be delayed, right?

Context validity can't be checked at that point of time.  The system of
available properties, however, is more or less considered static, so the
basic consistency checks for overriding existing/non-existing properties
are being done while parsing.  However, I consider it a bad idea to use
"insider" knowledge for parsing an override (meaning skip ahead until
finding a word declared as a grob property and split the input backwards
from there) since it means that understanding the input requires knowing
_all_ prospective properties, whether it is a human, a LilyPond
importer, a syntax highlighter, a cross referencing tool or LilyPond
itself that is trying to interpret the input.

>> LilyPond's parser is written with Bison, a standard parser generator
>> normally used for writing that part of a compiler that would deal
>> with syntax.  LilyPond's free-form language stretches the
>> capabilities of Bison beyond what it has been designed for.
>
> Interesting.  My knowledge here is very limited.

Mine isn't.  Educating people about the details takes a lot of time, and
it is time that only has a payoff if their ultimate goal is actually
working in that area rather than just satisfying their sense of being
taken seriously.  The problem is that there is an unlimited supply of
people with helpful suggestions, and if they come and go without having
acquired enough working knowledge to actually make a difference, or even
if they stay without working on connecting the dots to a degree where
their contributions become more focused, the net balance makes them feel
more important and me feeling more futile, with no new work being
accomplished, and the value of the actually accomplished work being
slighted or dismissed.

>> So let's just assume I have heard of compilers.  Give me a bit of
>> credit here.
>
> I don't doubt your capabilities.  I only refer to error messages which
> I've seen while working with C++ code.

At a climbers' weekend, I answered a call from my ex, afterwards
explaining apologizingly that I was sort of her support person for LaTeX
problems while she was doing her dissertation.  One of the climbers (who
I met there for the first time) pitched in with "Oh, I know someone who
could do this better".  This piqued my interest and I asked for his
name, being reasonably sure that I'd have heard of him, likely met him
in person already if this was the case.  Turned out that his
qualification was that he had written something akin to a dissertation
using LaTeX himself.

My ex could probably have run circles around him, and she was doing
Romance studies.  Now this incident was more amusing than anything else.

What I am getting at that it is taking enough effort and energy to work
and discuss on an item-per-item basis and bringing the discussion
partners up to scratch on that.  I don't actually have the means to
address "I feel sure others manage to do a better job under
circumstances I consider the same" in any meaningful manner: there are
too many technical details involved to address that.

The net result is the impression that I am seen as doing a subpar job,
making LilyPond worse than necessary either through incompetence or
obstinacy.  Whether this impression is one I get myself, or other people
interested in LilyPond: I doubt that it serves as a motivator.

So I would prefer if we tried discussing LilyPond as a system in its own
right rather than using sweeping comparisons with systems that are
actually quite dissimilar.  I just have a better chance of not tearing
out my hairs completely in vain then, and they are a limited resource.

-- 
David Kastrup