Lilypond's standard commands for organ pedal marks are: \lheel,
\ltoe, \rheel, \rtoe. However,
there are several ways of displaying these visually. Not all organists may
want Lilypond's default style, so this snippet provides some alternatives.
This snippet defines several pedal styles ("lilypond",
"modern", "traditional"), plus context-management
helpers to apply them conveniently. The "modern" style has inward-pointing toe marks (inwards towards
the staff, that is) and circular heel marks; this follows C.H. Trevor
(1971) "The Oxford Organ Method", Oxford University Press, Oxford, UK. The
"lilypond" style is of course Lilypond's default, with outward-pointing
toes and outward-pointing heels. The "traditional" style follows a
Bach/Novello 1948 standard and has upward-pointing toe marks and
downward-pointing heel marks (both as if the foot were pointing "toes up"
on the staff).
This snippet also defines some new pedal indicator commands, including for heel/toe transitions; foot slide marks (for sliding a foot forward/backward on a pedal); "foot behind"/"foot in front" marks, for crossing feet; "foot forward/backward" marks, for when feet are adjacent; and "foot substitution" (foot change, foot transition) marks, for swapping feet whilst pressing a single pedal. These augmented marks follow Trevor (1971, as above), and can be used with any of the pedal mark styles.
Finally, the snippet defines an engraver allowing you to show glide
(glissando) marks, e.g. sliding the right toe from one note to another,
using the standard Lilypond \glide command. (The engraver
for fingering glides should be disabled while pedal glides are in use, and
the snippet provides demonstrations and a convenience method for this.)
Full usage information is given in the comment block at the start of the snippet code.
For the Lilypond Snippet Repository, the snippet is self-contained and
includes a demonstration. For practical use, the snippet should be trimmed
below the comment "% organ_pedal_marks.ly ends here" and saved
as organ_pedal_marks.ly, ready for inclusion in other files
via the command \include "organ_pedal_marks.ly".