Re: request: better error message

[David Kastrup]

Thomas Morley <address@hidden> writes:

> 2017-11-08 23:40 GMT+01:00 David Kastrup <address@hidden>:
>> Thomas Morley <address@hidden> writes:
>>>
>>> {
>>>   \override Fingering #'stencil =
>>>     #(lambda (grob)
>>>       (ly:grob-set-property! grob 'stencil
>>>         (grob-interpret-markup grob #{ \markup \normal-text "foo" #})))
>>>   a''-1
>>> }
>>>
>>> I doubt many people would have been able to read the error and
>>> directly point to the faulty coding.
>>
>> Assertion failures should not be triggered by users anyway.  They point
>> to a violation of the program's assumptions severe enough that it makes
>> no sense to continue.  So this should likely become a programming error
>> instead.
>>
>> You still won't get sensible behavior here since the return value will
>> (I think) be wrong, too.
>
> I'm not that interested in a useful return value, but an (programming)
> error-message pointing to the location would be great.
> If not possible to point to the location, maybe something like "Can't
> set property 'stencil while setting 'stencil".
> Well, the wording is not accurate, but you may get the point!?

"Property 'stencil changed from inside callback." or something.

-- 
David Kastrup