Re: Confusion about beaming

[Peter Chubb]

>>>>> "Marc" == Marc Schonbrun <address@hidden> writes:

Marc> Hello, I was wondering about why the decision was made in the
Marc> input syntax parser to view beaming groups as follows:


Marc> \relative { c8 d [e f g a b c] }

Marc> The above snippet beams from the d through to the final c. At
Marc> first glance, it would appear that the brackets are encasing the
Marc> e through c, and those notes would end up beamed together, but,
Marc> alas, this is not the case.

LilyPond used to do treat brackets (for beaming) and parentheses (for
slurs and grouping) as grouping operators.  It was decided at one
point to change as much of the syntax as possible to be postfix -- so
`[' isn't a grouping symbol outside the start of a group, but a
`start-beam' operator attached to the note it follows.  Likewise (
isn't a grouping symbol but a 'start-slur' operator attached to the
note it follows.  If these symbols are treated as paired grouping operators,
it's difficult to handle nesting properly --- beams, slurs and phrase
marks are all independent groups.

This leaves { and } the only real grouping symbols, and they have to
nest strictly.  But slurs, phrasemarks and beams can span groups, and
each other.



--
Dr Peter Chubb                                  peter DOT chubb AT nicta.com.au
http://www.ertos.nicta.com.au               ERTOS within National ICT Australia
All things shall perish from under the sky/Music alone shall live, never to die