Re: Shortcut for \repeat unfold

[Lukas-Fabian Moser]

Hi Jean,
> I think it's a trap to see \repeat unfold as syntactic
> sugar for repeating a sequence of characters n times
> in the input. For instance,
>
> \relative { \repeat unfold 4 c'1 }
>
> is not the same as
>
> \relative { c'1 c'1 c'1 c'1 }

Yes, of course. But I'd be very surprised if a large percentage of 
relative mode users would really expect "f4., g8 an then four times c,8" 
really to produce \relative { c, c, c, c, }. (Maybe those with a 
background in computer science would :-).)

So, when I talked about "syntactic sugar" I didn't mean the literal 
character-copy-and-paste sense.

> Keyboards may be an important factor. Part of my
> dislike for \* comes from the fact that on French
> keyboards, the backslash is farther to the left,
> on the same key as 8, making it less convenient
> than what you describe.
>
> They are not the only factor though. Let's see how
> it looks visually:
>
> { c'1 \repeat 5 dis'8-_ c'1 }
>
> { c'1 \x 5 dis'8-_ c'1 }
>
> { c'1 \* 8 dis'8-_ c'1 }
>
> { c'1 dis'8-_**8 c'1 }
>
> With \x or \*, I find it harder to discern the structure.
> They are so small that they seem sprinkled over the input
> without grouping other elements -- the third one in
> particular looks like \* is some shortcut and 8 is
> a duration repeating the previous pitch as in { c'1 8 }.

I think you're making it harder to read than necessary: Why the space 
after \* / \x ?

> I like Werner's suggestion with ** better already.
> What worries me a bit is the difference with the
> existing use of *, which might be confusing. R1*5
> will be (most of the time) equivalent to R1**5,
> whereas c'1*5 will not be the same as c'1**5.
> Something like c'1\p**5 will be valid, contrary to
> c'1\p*5; c'1*4/5 will work but not c'1**4/5; …
>
> I have to think about it a bit more.
My gut feeling is that postfix ** might be dangerous/difficult to 
implement robustly. But feel free to ignore this uneducated guess. :-)
> I wouldn't push it so far -- it's easy enough to write
> a music function for the repeat style you use most
> often, just like you can shorten a lot of things
> with variables and music functions, even more
> conveniently now that we have \etc (let's hope the
> latter would start working with \repeat someday).

By now, I know a handful of "normal" musicians among my friends who use 
LilyPond for their occasional engraving tasks. From what they show me 
when they have questions, I think there is still a significant number of 
users that stay in the mode of "never defining anything new except music 
variables" (and are still able to produce impressive scores). Of course, 
the advent of \etc has made it extremely easy to create simple music 
functions without even realising it; but I still think a sentence like 
"it's easy enough to write a music function" makes a possible feature 
practically invisible/unattainable for a large percentage of users: The 
idea of defining parameterised short-hands is not familiar to many 
people without a maths/computer science background.

Lukas