Re: Project - Eliminating grob parents and outside-staff-priority

[address@hidden]

On 29 sept. 2012, at 19:53, "Keith OHara" <address@hidden> wrote:

> On Sat, 29 Sep 2012 10:30:32 -0700, address@hidden <address@hidden> wrote:
> 
>> 
>> The way you're using "tentative" is almost exactly how pure properties are 
>> used in LilyPond.
> 
> Specifically, 'pure-height being the estimated vertical extent before 
> line-breaking, while 'height is its extent after line-breaking.
> 
> If there are distinct properties to describe the position at different 
> stages, then each property can be evaluated just once (as HanWen suggested, 
> and as Mike agreed 100%).
> 
>> 
>> I think all property look-ups should be pure until one is absolutely certain 
>> that the property won't change, at which point the unpure value should be 
>> cached and returned for both pure and unpure queries (impure sounds too 
>> religious, thus unpure).  The pure properties need not always return the 
>> same value - they can get closer and closer to the unpure as more and more 
>> information gets determined.
> 
> This is the opposite approach, where some "properties" are not permanent at 
> all.  The word 'tentative' is a better label than 'pure', because pure 
> functions would always return the same value given the same arguments.
> 

True dat.  Someone wanna do a perl one-line replace subbing in tenative for 
pure and post the patch? :-)

Cheers,
MS