# This file is part of python-ly, https://pypi.python.org/pypi/python-ly
#
# Copyright (c) 2011 - 2015 by Wilbert Berendsen
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# See http://www.gnu.org/licenses/ for more information.
"""
Convert relative music to absolute music.
"""
from __future__ import unicode_literals
import itertools
import ly.lex.lilypond
[docs]
def rel2abs(cursor, language="nederlands", first_pitch_absolute=False):
"""Converts pitches from relative to absolute.
language: language to start reading pitch names in
first_pitch_absolute: if True, the first pitch of a \\relative expression
is regarded as absolute, when no starting pitch was given. This mimics
the behaviour of LilyPond >= 2.18.
(In fact, the starting pitch is then assumed to be f.)
If False, the starting pitch, when not given, is assumed to be c'
(LilyPond < 2.18 behaviour).
"""
start = cursor.start
cursor.start = 0
source = ly.document.Source(cursor, True, tokens_with_position=True)
pitches = ly.pitch.PitchIterator(source, language)
psource = pitches.pitches()
if start > 0:
# consume tokens before the selection, following the language
t = source.consume(pitches.tokens(), start)
if t:
psource = itertools.chain((t,), psource)
# this class dispatches the tokens. we can't use a generator function
# as that doesn't like to be called again while there is already a body
# running.
class gen(object):
def __iter__(self):
return self
def __next__(self):
t = next(psource)
while isinstance(t, (ly.lex.Space, ly.lex.Comment)):
t = next(psource)
if t == '\\relative' and isinstance(t, ly.lex.lilypond.Command):
relative(t)
t = next(psource)
elif isinstance(t, ly.lex.lilypond.MarkupScore):
consume()
t = next(psource)
return t
next = __next__
tsource = gen()
def makeAbsolute(p, lastPitch):
"""Makes pitch absolute (honoring and removing possible octaveCheck)."""
if p.octavecheck is not None:
p.octave = p.octavecheck
p.octavecheck = None
else:
p.makeAbsolute(lastPitch)
pitches.write(p)
def getpitches(iterable):
"""Consumes iterable but only yields Pitch instances."""
for p in iterable:
if isinstance(p, ly.pitch.Pitch):
yield p
def context():
"""Consume tokens till the level drops (we exit a construct)."""
depth = source.state.depth()
for t in tsource:
yield t
if source.state.depth() < depth:
return
def consume():
"""Consume tokens from context() returning the last token, if any."""
t = None
for t in context():
pass
return t
def relative(t):
pos = t.pos
lastPitch = None
t = next(tsource)
if isinstance(t, ly.pitch.Pitch):
lastPitch = t
t = next(tsource)
elif first_pitch_absolute:
lastPitch = ly.pitch.Pitch.f0()
else:
lastPitch = ly.pitch.Pitch.c1()
# remove the \relative <pitch> tokens
del document[pos:t.pos]
while True:
# eat stuff like \new Staff == "bla" \new Voice \notes etc.
if isinstance(source.state.parser(), ly.lex.lilypond.ParseTranslator):
t = consume()
elif isinstance(t, (ly.lex.lilypond.ChordMode, ly.lex.lilypond.NoteMode)):
t = next(tsource)
else:
break
# now convert the relative expression to absolute
if t in ('{', '<<'):
# Handle full music expression { ... } or << ... >>
for t in context():
# skip commands with pitches that do not count
if isinstance(t, ly.lex.lilypond.PitchCommand):
if t == '\\octaveCheck':
pos = t.pos
for p in getpitches(context()):
# remove the \octaveCheck
lastPitch = p
end = (p.accidental_token or p.octave_token or p.note_token).end
del document[pos:end]
break
else:
consume()
elif isinstance(t, ly.lex.lilypond.ChordStart):
# handle chord
chord = [lastPitch]
for p in getpitches(context()):
makeAbsolute(p, chord[-1])
chord.append(p)
lastPitch = chord[:2][-1] # same or first
elif isinstance(t, ly.pitch.Pitch):
makeAbsolute(t, lastPitch)
lastPitch = t
elif isinstance(t, ly.lex.lilypond.ChordStart):
# Handle just one chord
for p in getpitches(context()):
makeAbsolute(p, lastPitch)
lastPitch = p
elif isinstance(t, ly.pitch.Pitch):
# Handle just one pitch
makeAbsolute(t, lastPitch)
# Do it!
with cursor.document as document:
for t in tsource:
pass