prekern

prekern was written to assist with the encoding of musical scores into **kern encoding. It's a preprocessor for **kern. It adds context-dependency to the symbols. prekern takes a file with a single spine in context-dependent notation as input and outputs a file with the spine in **kern format.

prekern translates line by line into **kern format. The information that is not explicitly entered is "inherited" from the previous line.

The following rules apply:

• A line containing **prekern will be translated into a line with **kern.
• A line starting with !, * or = will just be copied.
• A line starting with % will be copied without the leading %. Thus the converting mechanism can be escaped.
• If the pitch is preceded by a @, the **kern interpretation is used to determine the octave. This should be used for the first note in the spine, and can be used for any subsequent note.
• If for a certain note the duration is not provided, the duration of the preceding note is used.
• If for a certain note the octave information is not provided, the note is taken that is nearest to the previous note (i.e. within a fifth).
• If a note is a fifth or more from the previous note, either @ followed by the **kern representation or one of the signs > (an octave higher) and < (an octave lower) should be used.
• The canonical order of **kern signifiers must be used.

An example to make things clear:

input: example.pk    output: example.krn

**prekern            **kern
*MM76                *MM76
*k[b-]               *k[b-]
*M4/4                *M4/4
=1                   =1
4@cc                 4cc
d                    4dd
e                    4ee
8f                   8ff
g                    8gg
=2                   =2
2a<                  2a
16b-                 16b-
c                    16cc
d                    16dd
e                    16ee
%16FFF               16FFF
g                    16gg
a                    16aa
d<                   16dd
=3                   =3
4@DD                 4DD
e                    4EE
f @G @b-             4FF 4G 4b-
e a c                4EE 4A 4cc
==                   ==
*-                   *-

To compile, put prekern.cc and prekern.h in the same directory and enter something like:

g++ -o prekern prekern.cc

on the command line, if you're using the GNU Compiler Collection. With other compilers, you're on your own. I provide this because it is helpful for me and it might be helpful for others. It is not under active development. Prekern is released under the GPL.