Re: New argument types (Was: Constructive Criticism and a Question)

[stk]

> . . . I'd always prefer extensions that do not change the syntax.

I can't argue with that preference.  But in

> >    \foo c \nul 4.  % \nul would be a sort of syntactic "breath mark"

the "\nul" would not constitute a change in syntax -- "\nul" would simply
be another LilyPond keyword.

\nul means this:  the preceding & following elements are separate items.

E.g., here, c \nul 4. is prevented from meaning c4.

Most programming languages make whitespace a symbol separator and
therefore do need a construct like \nul.  But LilyPond accepts
c 4. as meaning c4. so LilyPond will sometimes need a separator like \nul.

Such a keyword obviously would not need to be called "\nul"; it could be
called "\idem" and be thought of as an identity operator:
\idem c means c
\idem {c8 d e} means {c8 d e}
\idem 1*5/8 means 1*5/8
And   \foo c \idem 4.   means \foo has 2 args:  c  and  4.

-- Tom

************************************************************

On Mon, 8 Jan 2007, Bertalan Fodor wrote:

> When I was writing the Antlr version of the parser I realized that
> extending the grammar in dozens of ways makes much more complicatons and
> unreadability than you gain in compactness. Actually I don't like that I
> almost have to reimplement LilyPond just to be able to decide if an
> input is syntactically correct. :-)
>
> So I'd always prefer extensions that do not change the syntax. But I may
> be not right.
>
> Bert
>
> > ------- Original Message -------
> > From: address@hidden
> > To: Erik Sandberg <address@hidden>
> > Sent: 07. 01. 08., 5:54:21
> > Subject: New argument types (Was: Constructive Criticism and a Question)
> >
> > On Sun, 7 Jan 2007, Erik Sandberg wrote:
> >
> > > BTW, one of the biggest problems (IMHO) in the lilypond language is that
> > > we can't extend the parser to accept durations as parameters to music
> > > functions:  \foo c 4. is ambiguous; it's unclear whether the 4. is the
> > > c's duration, or if it's a separate argument.
> >
> > It's probably unfortunate that the choice was made to tolerate spaces in
> > things like
> >       c 4. ~
> > but I'm sure that that cannot be undone at this point.
> >
> > Increasing the number of different argument types for music functions
> > would almost certainly be extremely useful for users, who, judging from
> > this mailing list, seem to have an unlimited imagination when it comes to
> > wanting to be able to extend LP syntax.
> >
> > Since recognizing a duration expression is purely a notational problem
> > (in the sense that a notation has to be found that will be unambiguous for
> > the parser), it might be worth asking for people's ideas.  The things I
> > can think of offhand are the following --
> >
> >    \foo c (4.)     % no good -- confusion with slurs
> >    \foo c \nul 4.  % \nul would be a sort of syntactic "breath mark"
> >    \foo c \ 4.     % \ -- same idea as \nul (short, but maybe risky?)
> >    \foo c \\ 4.    % \\ -- same as \nul
> >    \foo c =4.      % = prefixed to any expression: "this is separate item"
> >
> > -- Tom
> > _______________________________________________
> > lilypond-user mailing list
> > address@hidden
> > http://lists.gnu.org/mailman/listinfo/lilypond-user