Re: Naming _another_ lacking puzzle piece

[Trevor Daniels]

David Kastrup wrote Sunday, October 14, 2012 10:56 AM


> "Trevor Daniels" <address@hidden> writes:
> 
>> David Kastrup wrote Sunday, October 14, 2012 9:21 AM
>>
>>
>>> "Trevor Daniels" <address@hidden> writes:
>>>
>>>> I would be happier with this change.  Why not just change the action
>>>> of \override to be push alone?  As its current implementation pretty
>>>> well ensures all the stacks are empty, changing its action to be
>>>> push rather than pop+push would have a limited effect on existing
>>>> scores, wouldn't it?
>>> 
>>> Exactly _because_ the current implementation pretty well ensures that
>>> all the stacks are empty or close to empty, changing its action to
>>> _not_ ensure empty stacks would have a _large_ effect on existing
>>> scores.
>>
>> I'm not so sure. > 
> Well, I did the detective work of tracking down _when_ the change was
> made (October 2005 by Han-Wen).  So there is already a history of
> LilyPond with this decision made differently.

[snip]

Well, yes, I know all that.  My point is that we don't know the reasons
for the decision made in 2005, so we need to consider the best interface
for LilyPond _today_, which is markedly different to LilyPond in 2005.
I don't think the effect of changing \override to push only would be
very dramatic, to either the documentation or in its effect on existing
scores.  The old version of \override could easily be simulated by 
prepending a \clear (or \setToDefault or whatever) as Joe suggested if
people wanted the current action to continue. 

In debating this issue we need to consider users writing complex music, 
rather than songs or one-line melodies - they wouldn't really be affected.  
Would a proper push/pop action of \override-\revert offer advantages to 
them without having to use \temporary?  I don't know the answer to that 
as I don't write terribly complex  music, although I'd prefer it, as it was the
action I expected when I first started using and documenting LilyPond.  
But if the answer is, "No", then I'm content to go along with your \temporary 
suggestion, and work out a way to document it as effectively as possible.  
But I'd like to see a few more responses first.

To clarify, the two alternative we are discussing are

A. 
\override does a pop/push
\revert does a pop
\temporary\override does a push.

so \temporary\override and \revert are a matching pair.

B
\override does a push
\revert does a pop
\clear restores the stack to the default state.

so \override and \revert are a matching pair.

Both of these are essentially equivalent, except A does not have a stack
clear operation, but which of these is the clearer, and which the more 
intuitive?

Trevor