On Tue, Apr 14, 2020 at 9:28 AM <jonas.hahnf...@gmail.com> wrote: > > On 2020/04/14 07:24:10, hanwenn wrote: > > On 2020/04/14 07:00:56, hahnjo wrote: > > > On 2020/04/13 21:01:11, hanwenn wrote: > > > > it's hard to say if this makes a measurable difference: > > > > > > > > [...] > > > > > > So then ... why do it at all? From a code perspective, a deep copy > looks saner > > > in terms of "encapsulation" (one principle of object-oriented > programming). If > > > there is no provable gain, I'm for leaving the current code alone > until there > > is > > > good reason to change - "premature optimization is the root of all > evil" > > > > As I described in the commit message, this code doesn't protect > anything, > > because get_property can also return values from the immutable list. > > get_property uses data backed by mutable_property_alist_, right?
Use the Source, Jonas! https://github.com/lilypond/lilypond/blob/0c00cd98e81b27325bed5891b950fe7f0f0ebe5d/lily/grob-property.cc#L140 it reads from the immutable_list_ if there is no override in the mutable property list. If anything modifies an indirect value they get from get_property, they break the entire formatting process in a grotesque way, because they'd potentially be modifying shared state that is kept in immutable_property_alist_. -- Han-Wen Nienhuys - hanw...@gmail.com - http://www.xs4all.nl/~hanwen
