rhythm [Item Type]

A logical rhythm value. A logical rhythm can be symbolic or numeric. If numeric, the value represents the number of divisions of a whole note the time value occupies. For example, 4 means quarter note, 16 means sixteenth note, 7 means seventh note, and so on. If the logical rhythm is a symbol then it can be the ordinal equivalent of a number, i.e. 4er, 16th, 7th and so on, or else one of the rhythmic tokens m l b w h q e s which correspond to double, long, whole, half, quarter, eighth and sixteenth-note values, respectively. Here is a table showing some common logical notations:

Note Value       Logical Notations
               Symbol Number Ordinal
Maxima           M     1/8
Longa            L     1/4
Brevis           B     1/2
Whole            W      1      1st
Half             H      2      2nd
Quarter          Q      4      4th
5:4 (quarters)          5      5th
Eighth           E      8      8th
10:8 (eighths)         10     10th
Sixteeth         S     16     16th
Thirty-second          32     32nd
Sixty-fourth           64     64th
Any logical rhythm may be made triplet by prefixing t to it. For example, tq and t4 both mean triplet quarter note. A logical rhythm may also have any number of dots appended to it, i.e. tq., h..., 7th. and so on. Finally, complex rhythmic values may be written using + - * operators: w+e., q-t64, w*2-s, and so on. No space may separate the operators from the operands and the expression is parsed from left to right without any notion of operator precedence.

There is one caveat when writing dotted rhythms. Lisp reads a dotted integer value like 4. as the integer 4 without the dot. This means that Common Music cannot parse an integer followed by a single dot as a logical rhythm because it never sees the single dot! There are two ways to avoid this problem: use the ordinal form of the number, i.e. 4th. or 32nd. or else delimit the token using the | character, as in |4.| or |16.|, which forces the Lisp reader to interpret the token as a symbol. Numbers followed by more than one dot, for example, 16.. or 8..., are not read as numbers by Lisp and are parsed correctly.

See Also:

rhythm [Function], rhythms


Last Modified: 5-Mar-1998