Parser: harmonize \lyricsto and \addlyrics arguments

Parser: harmonize \lyricsto and \addlyrics arguments

Previously, they allowed arbitrary music but since that required looking
at lookahead tokens in the wrong mode, it led to strange errors like with
lyr=\lyricsto A { }
mus={c}
when mus= was parsed as a single token in lyrics mode.  Now both \addlyrics
and \lyricsto accept merely the same kind of delimited argument list
that \lyrics or \chords accept.  Additionally, to preserve compatibility
to a lot of examples, music identifiers like \mus are permitted as the
argument to \lyricsto and \addlyrics.

[lemzwerg, 2014-01-16 11:08:59]

LGTM.

[dak, 2014-01-16 13:29:25]

convert-ly rules for harmonizing \lyricsto usage

[lemzwerg, 2014-01-16 13:55:43]

A side question: What about a syntax like

  \new Lyrics \with
  { lyricsto = "bla" }
  { bla al blob blob }

to be in sync with other modes?

[dak, 2014-01-16 13:58:17]

On 2014/01/16 13:55:43, lemzwerg wrote:
> A side question: What about a syntax like
> 
>   \new Lyrics \with
>   { lyricsto = "bla" }
>   { bla al blob blob }
> 
> to be in sync with other modes?

How would that be "in sync with other modes"?  You assign to a context variable
that is not being used, and magically throw the argument into lyricmode because
of that?

[dak, 2014-01-16 14:43:31]

Further pattern fixes

[janek, 2014-01-16 19:49:16]

So, does it mean that i'll be able to write

\mus = { c'2 d'8 e' f' g' }

<<
  \new Staff \mus
  \new Lyrics \lyricsto \mus
>>

?

[dak, 2014-01-16 19:55:40]

On 2014/01/16 19:49:16, janek wrote:
> So, does it mean that i'll be able to write
> 
> \mus = { c'2 d'8 e' f' g' }
> 
> <<
>   \new Staff \mus
>   \new Lyrics \lyricsto \mus
> >>
> 
> ?

What would make you even think that?

[janek, 2014-01-16 19:57:11]

On 2014/01/16 19:55:40, dak wrote:
> On 2014/01/16 19:49:16, janek wrote:
> > So, does it mean that i'll be able to write
> > 
> > \mus = { c'2 d'8 e' f' g' }
> > 
> > <<
> >   \new Staff \mus
> >   \new Lyrics \lyricsto \mus
> > >>
> > 
> > ?
> 
> What would make you even think that?

"music identifiers like \mus are permitted as the
argument to \lyricsto and \addlyrics"

[janek, 2014-01-16 19:58:32]

On 2014/01/16 19:57:11, janek wrote:
> On 2014/01/16 19:55:40, dak wrote:
> > On 2014/01/16 19:49:16, janek wrote:
> > > So, does it mean that i'll be able to write
> > > 
> > > \mus = { c'2 d'8 e' f' g' }
> > > 
> > > <<
> > >   \new Staff \mus
> > >   \new Lyrics \lyricsto \mus
> > > >>
> > > 
> > > ?
> > 
> > What would make you even think that?
> 
> "music identifiers like \mus are permitted as the
> argument to \lyricsto and \addlyrics"

Uh, sorry, my example was incomplete (and had a syntax error).  I meant it to be

mus = { c'2 d'8 e' f' g' }
text = \lyricmode { tro -- lo -- lo bing bong }

<<
  \new Staff \mus
  \new Lyrics \lyricsto \mus \text
>>

[dak, 2014-01-16 19:59:25]

On 2014/01/16 19:57:11, janek wrote:
> On 2014/01/16 19:55:40, dak wrote:
> > On 2014/01/16 19:49:16, janek wrote:
> > > So, does it mean that i'll be able to write
> > > 
> > > \mus = { c'2 d'8 e' f' g' }
> > > 
> > > <<
> > >   \new Staff \mus
> > >   \new Lyrics \lyricsto \mus
> > > >>
> > > 
> > > ?
> > 
> > What would make you even think that?
> 
> "music identifiers like \mus are permitted as the
> argument to \lyricsto and \addlyrics"

\lyricsto takes two arguments only the second of which is a music expression. 
What would it even _mean_ to replace the context name with a music expression?

[dak, 2014-01-16 20:01:54]

On 2014/01/16 19:58:32, janek wrote:
> On 2014/01/16 19:57:11, janek wrote:
> > On 2014/01/16 19:55:40, dak wrote:
> > > On 2014/01/16 19:49:16, janek wrote:
> > > > So, does it mean that i'll be able to write
> > > > 
> > > > \mus = { c'2 d'8 e' f' g' }
> > > > 
> > > > <<
> > > >   \new Staff \mus
> > > >   \new Lyrics \lyricsto \mus
> > > > >>
> > > > 
> > > > ?
> > > 
> > > What would make you even think that?
> > 
> > "music identifiers like \mus are permitted as the
> > argument to \lyricsto and \addlyrics"
> 
> Uh, sorry, my example was incomplete (and had a syntax error).  I meant it to
be
> 
> mus = { c'2 d'8 e' f' g' }
> text = \lyricmode { tro -- lo -- lo bing bong }
> 
> <<
>   \new Staff \mus
>   \new Lyrics \lyricsto \mus \text
> >>

Still meaningless as \lyricsto would have no way to guess the associated
context.

[janek, 2014-01-16 20:09:32]

2014/1/16  <dak@gnu.org>:
> On 2014/01/16 19:58:32, janek wrote:
>> mus = { c'2 d'8 e' f' g' }
>> text = \lyricmode { tro -- lo -- lo bing bong }
>>
>> <<
>>    \new Staff \mus
>>    \new Lyrics \lyricsto \mus \text
>> >>
>
>
> Still meaningless as \lyricsto would have no way to guess the associated
> context.

ah, ok.

[dak, 2014-01-17 08:59:28]

When replying to a code review, please at least keep the URL of the
review in the body of the mail, or the review will not be visible on
Rietveld.

> From: Werner LEMBERG <wl@gnu.org>
> Subject: Re: Parser: harmonize \lyricsto and \addlyrics arguments (issue
53120044)
> To: dak@gnu.org, reply@codereview-hr.appspotmail.com
> Date: Fri, 17 Jan 2014 08:44:28 +0100 (CET) (48 minutes, 26 seconds ago)
> 
> 
> >> A side question: What about a syntax like
> >
> >>    \new Lyrics \with
> >>    { lyricsto = "bla" }
> >>    { bla al blob blob }
> >
> >> to be in sync with other modes?
> >
> > How would that be "in sync with other modes"?  You assign to a
> > context variable that is not being used, and magically throw the
> > argument into lyricmode because of that?
> 
> Sorry for being imprecise.  The idea of \lyricsto is basically to
> associate lyrics with a note context, as far as I can see.  It seems
> to me that this is kind of a property.  We already can do this:
> 
>   <<
>     \new Staff = "staff"
>     {
>       \new Voice = "melody"
>       {
>         \relative c'' { c4 c c c }
>       }
>     }
>     \new Lyrics \with
>       { alignAboveContext = "staff" }
>     {
>       \lyricsto "melody"
>       {
>         Here are the words
>       }
>     }
>   >>
> 
> I now wonder why we can't do
> 
>   <<
>     \new Staff = "staff"
>     {
>       \new Voice = "melody"
>       {
>         \relative c'' { c4 c c c }
>       }
>     }
>     \new Lyrics \with
>       { alignAboveContext = "staff"
>         lyricsTo = "melody" }
>     {
>       Here are the words
>     }
>   >>
> 
> Please look at the idea at a whole and don't get distracted by
> potential syntax errors in my ad-hoc suggestion.

What's the advantage?

At any rate, context properties can be changed over the lifetime of a
context.  Synchronizing lyrics to a context is a decision that
requires using a different iterator because of using quite a different
algorithm: the whole timing is affected.  So in contrast to context
properties, one cannot change horses in midstream.  Among other
things, a combined lyric implies that the natural length of the lyrics
itself must be _ignored_ by LilyPond when it does music length
calculations.  To do that, one needs to distinguish rerhythmed lyrics
at the music expression level already.  A context property (which may
well be defined at a later point of time in a layout definition) is
not available for making that decision at the time it needs to be
done.

[lemzwerg, 2014-01-17 09:44:05]

> What's the advantage?

Harmonized, uniform syntax, but...

> A context property (which may well be defined at a later
> point of time in a layout definition) is not available
> for making that decision at the time it needs to be done.

... this explains why it doesn't work, thanks.