Re: request: better error message

[Thomas Morley]

2017-11-08 23:56 GMT+01:00 David Kastrup <address@hidden>:
> 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.



Yeah, that would have been really helpful.

Cheers,
  Harm