Re: conversion rule for set-octavation/ottava with wrong version number?

[David Kastrup]

Malte Meyn <address@hidden> writes:

> Am 01.11.2017 um 10:43 schrieb Malte Meyn:
>> One could have the same convert-ly rule twice: First time for the
>> version where a new feature is introduced and it’s *possible and
>> recommended* to use it. Second time for the version where the old
>> feature (and thus backward compatibility) is removed and you *have
>> to* use it.
>
> F. e. if the \override syntax
>
>       \override Staff.TimeSignature #'color = #red
>
> is removed some day IMO one would have to add the convert-ly rule that
> turns it to
>
>       \override Staff.TimeSignature.color = #red
>
> again because many people still use the old syntax that they find in
> old code.

I don't really agree: that way lies madness.  Do we take the time when
something stops working reliably, or the time when it stops working
altogether?  I do try to keep rules "idempotent" as much as possible,
making it harmless to apply them multiple times in a row.  That allows
just trying another sweeping convert-ly run.  But this isn't really
possible for all rules.

-- 
David Kastrup