>> This works:
>>
>> ```
>> { \ottava -1 c }
>> ```
>>
>> while this fails:
>>
>> ```
>> { \ottava +1 c'' }
>> ```
>>
>> Is there a technical reason for it?
>
> As far as LilyPond is concerned, `+` is not a part of numbers. Is
> there a compelling argument for wasting syntactic elements on doing
> nothing?
I think that 'wasting' is too harsh a statement. In comparison to
other syntactical elements (together with the interpretation of Scheme
code), a change to support `+` has no significant impact, AFAICS.
Can you imagine any other use for `+` right before numbers? Otherwise
I suggest to make it work, to provide the least surprise for users.
Werner
