Re: Defining a function that passes contents between braces to a markup

[David Kastrup]

Mojca Miklavec <address@hidden> writes:

> Hi,
>
> I've learnt some basics of scheme and managed to write some simple
> functions, but I'm unable to figure out how to write a function that
> would take all the contents between braces as an argument and return a
> markup.
>
> I would be grateful even if I get just the simplified version working, so that
>
>     \A {<foo>}
>
> would be translated into
>
>     \markup { \small \override #'(direction . 1) { \dir-column { <foo> } } }

Well, first thing to note is that scheme/music functions do not switch
modes for their arguments.  So you either need to write something like

\A \markup <foo>

here to get something in markup mode, or be in lyrics mode (which
interprets <foo> as lyrics), \A should be a markup command and are
already in markup mode, like \markup \A <foo> .

> I would use this markup as part of the lyrics as in
>
>     \lyricsto "melody" {
>         \A {foo bar}
>         \A {three short lines}
>         \A {one}
>     }

Ah, we are in lyrics mode already.  That simplifies things.  Your
arguments will then be of type ly:music? and you'll pick off the
respective markup from the 'text field of the lyrics.

> In a slightly more advanced version it would be nice to be able to type
>
>     \lyricsto "melody" {
>       % \command { array of values }
>       %            each entry can have an optional "-<number>"
>       \A {A1-1}
>       \A {A1-1 C2-2}
>       \A {A1-1 C2-2 E2-3}
>       \A {C2 E2-3}
>       \A {E2}
>     }

Lyrics mode does not really take text scripts I think.  All of A1-1 will
likely end up one lyrics syllable.

> So far I came up with a function definition
>
> M = #(define-scheme-function (parser location aFinger aButton) (markup? 
> markup?)
>   #{ \markup{ \small \bold \with-color #(rgb-color 0.5 0 0) #aFinger
> \small \with-color #(rgb-color 0 0 0.5) #aButton } #}
> )
> that can handle input like
>     \M "1" "A1"
> and then I would enter multiple lines of lyrics, but this is tedious
> to write, even more so when the number of lines varies from one pitch
> to the other.

Strings are the most simple form of markup, but I guess that pretty much
everything else needs to be explicitly preceded by \markup.  You could
work here with an optional finger argument as a number:

M =
#(define-scheme-function (parser location aFinger aButton) ((number?) markup?)
   (if afinger  
       #{ \markup{ \small \bold \with-color #(rgb-color 0.5 0 0) #aFinger
       \small \with-color #(rgb-color 0 0 0.5) #aButton } #}
       ;; #{ \markup whatever you want here when no finger is given #}
       ))

which can handle then both
    \M 1 "A1"
as well as
    \M "A1"

That's basically what I can think of out of the box right now.

-- 
David Kastrup