Re: Create Score context before starting iteration. (issue 44860045)

[dak]

https://codereview.appspot.com/44860045/diff/60001/Documentation/contributor/programming-work.itexi
File Documentation/contributor/programming-work.itexi (right):

https://codereview.appspot.com/44860045/diff/60001/Documentation/contributor/programming-work.itexi#newcode43
Documentation/contributor/programming-work.itexi:43: event a moment (a
time) and a context, which is the environment in which the
No, events are not assigned a time.  And neither are they assigned a
context.

Iteration interprets music expressions through "iterators".  Most of the
effects are subsequently produced through "stream events".  Events are
"broadcast" by iterators in a particular context at a given global time.
 This broadcast is received by event listeners, usually in the form of
"translators" (in the printed output, "engravers") in the context or any
parent context.  The translators are responsible for initiating further
processing.

https://codereview.appspot.com/44860045/diff/60001/Documentation/contributor/programming-work.itexi#newcode1578
Documentation/contributor/programming-work.itexi:1578: @item @code{ok
()} returns whether there are any events left to send.
I think that ok () is only relevant when the iterator is of the
run_always kind.  If it isn't, pending_mom () gives the next time of
call.

Don't consider this authoritive: that's more or less what I tried
figuring out from the code and remember right now without actually
cross-checking.

But it might help you get a better idea of what to write here actually
after checking the code again.

https://codereview.appspot.com/44860045/diff/60001/input/regression/initial-contexts.ly
File input/regression/initial-contexts.ly (right):

https://codereview.appspot.com/44860045/diff/60001/input/regression/initial-contexts.ly#newcode10
input/regression/initial-contexts.ly:10: %%and iteration can't skip time
without it.
This comment is a bit of a non-sequitur: time is kept in the Global
context, so it could get skipped.  I am not actually sure how SkipEvent
even works.

https://codereview.appspot.com/44860045/diff/60001/lily/global-context.cc
File lily/global-context.cc (right):

https://codereview.appspot.com/44860045/diff/60001/lily/global-context.cc#newcode135
lily/global-context.cc:135: //Maybe they should be called directly
rather than through events.
If you called them directly, the EventListener framework used for
quoting and part combining would stop working.

https://codereview.appspot.com/44860045/diff/60001/lily/global-context.cc#newcode148
lily/global-context.cc:148: find_create_context (default_child_, "",
SCM_EOL);
This precludes \new Score \with ..., quite a no-no.

https://codereview.appspot.com/44860045/diff/60001/lily/translator-group.cc
File lily/translator-group.cc (right):

https://codereview.appspot.com/44860045/diff/60001/lily/translator-group.cc#newcode232
lily/translator-group.cc:232: if (!new_context->now_mom
().main_part_.is_infinity ())
Don't understand that condition.

https://codereview.appspot.com/44860045/diff/60001/lily/translator-group.cc#newcode235
lily/translator-group.cc:235: DOWN);
Isn't that sufficient to have the Score context created in time?
Without requiring the other fixes?

https://codereview.appspot.com/44860045/diff/60001/ly/engraver-init.ly
File ly/engraver-init.ly (right):

https://codereview.appspot.com/44860045/diff/60001/ly/engraver-init.ly#newcode527
ly/engraver-init.ly:527: @code{\\score} or @code{\\layout} block) is
processed."
If a Score context would be created automatically when an output
definition is processed, one _could_ not create it explicitly
afterwards.  These two sentences are contradictory.

https://codereview.appspot.com/44860045/