Re: Allow Scheme functions to be called inside of markup (issue 285070043 by address@hidden)

[dak]

Reviewers: thomasmorley651,

Message:
On 2016/01/16 19:54:54, thomasmorley651 wrote:
> After some testings I'm quite happy with it, apart from one use case:

> fooII =
> #(define-scheme-function (arg)(markup-list?)
> #{
>    \markup \column $arg
> #})

> %% doesn't work:
> \markup \line { "xy" \fooII { "does" "not" "work"} }
> %% works
> \markup \line { "xy" \fooII \markuplist { "whatever" "else" } }
> \markup \line { "xy" \fooII #'("whatever" "else") }

> I think I know why the first case doesn't work. Though, I have no good
idea how
> to explain it in the docs without telling a very technical story,
likely very
> confusing to the average-user.
> Additionally, having to add \markuplist as in the second example is
not nice.
> Only a little better is the need to revert to scheme as done in the
third
> example.

> What other problematic cases can you predict deductively?

Sigh.  This looks like a can of worms.

Arguments of type markup?/markup-list? will obviously be problematic
(apart from the trivial case of strings) without explicit
\markup/\markuplist.  I am afraid that one would need to teach
markup-mode internal arguments to generic function argument lists.  That
would appear to be a likely user expectation.

However, `{' and `}' are mode-independent, and so { } already stands for
an empty sequential music expression and making it stand at the same
time for an empty markup list...  Ugh.

So much for the triviality of the change.

Description:
Allow Scheme functions to be called inside of markup

Please review this at https://codereview.appspot.com/285070043/

Affected files (+1, -1 lines):
  M lily/parser.yy


Index: lily/parser.yy
diff --git a/lily/parser.yy b/lily/parser.yy
index  
c60c6ed64c1157fa00e516efdcd98b8cb9e9eb0b..f09b437fa3a5b43709b033f7bbea22357f2e737b  
100644
--- a/lily/parser.yy
+++ b/lily/parser.yy
@@ -3693,7 +3693,7 @@ markup_top:
        ;

 markup_scm:
-       embedded_scm_bare
+       embedded_scm
        {
                if (Text_interface::is_markup ($1))
                        MYBACKUP (MARKUP_IDENTIFIER, $1, @1);