5.3. Beams

beam     ::=  (beam beamId beamtype)
beamId   ::=  integer number
beamtype ::=  string. See description

Beam segments are represented by a string, encoded in the beamtype element. The string is formed by concatenation of 1 to 6 characters from the set { + | - | = | f | b }. Each caracter is associated to a beam level: the first character to the first level, the second character to the second level, etc. An the caracters have the following meaning:

• ‘+’ for start beam. It starts a new beam and must be paired with a ‘-‘ in another note.
• ‘=’ for continue beam. Must be included in intermediate notes.
• ‘-‘ for end beam. It stops a beam started in another note.
• ‘f’ for forward hook. For specifying a single beam forward hook that only affects the note in which it is defined.
• ‘b’ for backward hook For specifying a single beam backward hook that only affects the note in which it is defined.

For instance, lets define the beam for the group in following image:

The beam will be assigned, arbitrarily, the ID 31. In first note one beam line starts; this is encoded as (beam 31 +). In second note the first beam line continues (‘=’), a second line starts (‘+’) and has a forward hook (‘f’); therefore, the beam in second note will be encoded as (beam 31 =+f). The third note has two beam lines that continue from previous note; therefore the beam is encoded as (beam 31 ==). Finally, in the last note the two beams end and there is a backwards hook; therefore (beam 31 --b). This is the score:

(score (vers 2.0) (instrument (musicData
    (clef G)
    (n e4 e (beam 31 +))
    (n g4 t (beam 31 =+f))
    (n d4 s (beam 31 ==))
    (n f4 t (beam 31 --b))
    (spacer 30)
    (barline)
)))

Some more examples:

(score (vers 2.0) (instrument (musicData
    (clef G)
    //first group
    (n c4 e (beam 17 +))
    (n d4 e (beam 17 =))
    (n e4 e (beam 17 =))
    (n g4 e (beam 17 -))

    //second group
    (n c4 s (beam 18 +f))
    (n d4 e (beam 18 =))
    (n f4 s (beam 18 -b))

    //third group
    (n c4 t (beam 19 ++))
    (n d4 t (beam 19 ==))
    (n e4 t (beam 19 ==))
    (n f4 t (beam 19 --))
)))

For beams in chords the beam element must be placed only in the first note of each chord included in the beam. Example, two beamed chords:

(score (vers 2.0) (instrument (musicData
    (clef G)
    (chord (n e4 e. (beam 31 +)) (n g4 e.) (n c5 e.))
    (chord (n d4 s (beam 31 -b)) (n f4 s) (n a4 s))
)))

5.3.1. Abbreviated notation (deprecated)

LDP also supports an abbreviated syntax for beams in simple lines of music. It consists on marking only the first note of the beamed group with a g+ notation and the last note of the group with a g- notation. All notes defined between these two will be automatically included in the beam, and the beam segments will be automatically computed based on notes duration. Example:

(score (vers 2.0) (instrument (musicData
    (clef G)
    (key C)
    (time 2 4)

    //Measure 1
    (n c4 e. g+ v1)
    (n d4 s v1)
    (n e4 e g- v1)
    (n c4 s g+ v1)
    (n d4 s v1)
    (n e4 e g- v1)
    (barline simple)

    //Measure 2
    (n c4 s g+ v1)
    (n d4 e v1)
    (n e4 s g- v1)
    (n c4 s g+ v1)
    (n d4 s v1)
    (n d4 s v1)
    (n e4 s g- v1)
    (barline simple)

    //Measure 3
    (n c4 s g+ v1)
    (n d4 e. g- v1)
    (n c4 t g+ v1)
    (n d4 e v1)
    (n d4 t v1)
    (n e4 s g- v1)
    (barline simple)

    //Measure 4
    (n c4 s g+ v1)
    (n d4 t v1)
    (n d4 t v1)
    (n e4 e g- v1)
    (n c4 s g+ v1)
    (n d4 t v1)
    (n d4 e v1)
    (n e4 t g- v1)
    (barline simple)
)))