Module note_seq.abc_parser
Parser for ABC files.
http://abcnotation.com/wiki/abc:standard:v2.1
Expand source code
# Copyright 2021 The Magenta Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Parser for ABC files.
http://abcnotation.com/wiki/abc:standard:v2.1
"""
import fractions
import re
from absl import logging
from note_seq import constants
from note_seq.protobuf import music_pb2
Fraction = fractions.Fraction
class ABCParseError(Exception):
"""Exception thrown when ABC contents cannot be parsed."""
pass
class MultiVoiceError(ABCParseError):
"""Exception when a multi-voice directive is encountered."""
class RepeatParseError(ABCParseError):
"""Exception when a repeat directive could not be parsed."""
class VariantEndingError(ABCParseError):
"""Variant endings are not yet supported."""
class PartError(ABCParseError):
"""ABC Parts are not yet supported."""
class InvalidCharacterError(ABCParseError):
"""Invalid character."""
class ChordError(ABCParseError):
"""Chords are not supported."""
class DuplicateReferenceNumberError(ABCParseError):
"""Found duplicate reference numbers."""
class TupletError(ABCParseError):
"""Tuplets are not supported."""
def parse_abc_tunebook_file(filename):
"""Parse an ABC Tunebook file.
Args:
filename: File path to an ABC tunebook.
Returns:
tunes: A dictionary of reference number to NoteSequence of parsed ABC tunes.
exceptions: A list of exceptions for tunes that could not be parsed.
Raises:
DuplicateReferenceNumberError: If the same reference number appears more
than once in the tunebook.
"""
# 'r' mode will decode the file as utf-8 in py3.
return parse_abc_tunebook(open(filename, 'r').read())
def parse_abc_tunebook(tunebook):
"""Parse an ABC Tunebook string.
Args:
tunebook: The ABC tunebook as a string.
Returns:
tunes: A dictionary of reference number to NoteSequence of parsed ABC tunes.
exceptions: A list of exceptions for tunes that could not be parsed.
Raises:
DuplicateReferenceNumberError: If the same reference number appears more
than once in the tunebook.
"""
# Split tunebook into sections based on empty lines.
sections = []
current_lines = []
for line in tunebook.splitlines():
line = line.strip()
if not line:
if current_lines:
sections.append(current_lines)
current_lines = []
else:
current_lines.append(line)
if current_lines:
sections.append(current_lines)
# If there are multiple sections, the first one may be a header.
# The first section is a header if it does not contain an X information field.
header = []
if len(sections) > 1 and not any(
line.startswith('X:') for line in sections[0]):
header = sections.pop(0)
tunes = {}
exceptions = []
for tune in sections:
try:
# The header sets default values for each tune, so prepend it to every
# tune that is being parsed.
abc_tune = ABCTune(header + tune)
except ABCParseError as e:
exceptions.append(e)
else:
ns = abc_tune.note_sequence
if ns.reference_number in tunes:
raise DuplicateReferenceNumberError(
'ABC Reference number {} appears more than once in this '
'tunebook'.format(ns.reference_number))
tunes[ns.reference_number] = ns
return tunes, exceptions
class ABCTune(object):
"""Class for parsing an individual ABC tune."""
# http://abcnotation.com/wiki/abc:standard:v2.1#decorations
DECORATION_TO_VELOCITY = {
'!pppp!': 30,
'!ppp!': 30,
'!pp!': 45,
'!p!': 60,
'!mp!': 75,
'!mf!': 90,
'!f!': 105,
'!ff!': 120,
'!fff!': 127,
'!ffff!': 127,
}
# http://abcnotation.com/wiki/abc:standard:v2.1#pitch
ABC_NOTE_TO_MIDI = {
'C': 60,
'D': 62,
'E': 64,
'F': 65,
'G': 67,
'A': 69,
'B': 71,
'c': 72,
'd': 74,
'e': 76,
'f': 77,
'g': 79,
'a': 81,
'b': 83,
}
# http://abcnotation.com/wiki/abc:standard:v2.1#kkey
SIG_TO_KEYS = {
7: ['C#', 'A#m', 'G#Mix', 'D#Dor', 'E#Phr', 'F#Lyd', 'B#Loc'],
6: ['F#', 'D#m', 'C#Mix', 'G#Dor', 'A#Phr', 'BLyd', 'E#Loc'],
5: ['B', 'G#m', 'F#Mix', 'C#Dor', 'D#Phr', 'ELyd', 'A#Loc'],
4: ['E', 'C#m', 'BMix', 'F#Dor', 'G#Phr', 'ALyd', 'D#Loc'],
3: ['A', 'F#m', 'EMix', 'BDor', 'C#Phr', 'DLyd', 'G#Loc'],
2: ['D', 'Bm', 'AMix', 'EDor', 'F#Phr', 'GLyd', 'C#Loc'],
1: ['G', 'Em', 'DMix', 'ADor', 'BPhr', 'CLyd', 'F#Loc'],
0: ['C', 'Am', 'GMix', 'DDor', 'EPhr', 'FLyd', 'BLoc'],
-1: ['F', 'Dm', 'CMix', 'GDor', 'APhr', 'BbLyd', 'ELoc'],
-2: ['Bb', 'Gm', 'FMix', 'CDor', 'DPhr', 'EbLyd', 'ALoc'],
-3: ['Eb', 'Cm', 'BbMix', 'FDor', 'GPhr', 'AbLyd', 'DLoc'],
-4: ['Ab', 'Fm', 'EbMix', 'BbDor', 'CPhr', 'DbLyd', 'GLoc'],
-5: ['Db', 'Bbm', 'AbMix', 'EbDor', 'FPhr', 'GbLyd', 'CLoc'],
-6: ['Gb', 'Ebm', 'DbMix', 'AbDor', 'BbPhr', 'CbLyd', 'FLoc'],
-7: ['Cb', 'Abm', 'GbMix', 'DbDor', 'EbPhr', 'FbLyd', 'BbLoc'],
}
KEY_TO_SIG = {}
for sig, keys in SIG_TO_KEYS.items():
for key in keys:
KEY_TO_SIG[key.lower()] = sig
KEY_TO_PROTO_KEY = {
'c': music_pb2.NoteSequence.KeySignature.C,
'c#': music_pb2.NoteSequence.KeySignature.C_SHARP,
'db': music_pb2.NoteSequence.KeySignature.D_FLAT,
'd': music_pb2.NoteSequence.KeySignature.D,
'd#': music_pb2.NoteSequence.KeySignature.D_SHARP,
'eb': music_pb2.NoteSequence.KeySignature.E_FLAT,
'e': music_pb2.NoteSequence.KeySignature.E,
'f': music_pb2.NoteSequence.KeySignature.F,
'f#': music_pb2.NoteSequence.KeySignature.F_SHARP,
'gb': music_pb2.NoteSequence.KeySignature.G_FLAT,
'g': music_pb2.NoteSequence.KeySignature.G,
'g#': music_pb2.NoteSequence.KeySignature.G_SHARP,
'ab': music_pb2.NoteSequence.KeySignature.A_FLAT,
'a': music_pb2.NoteSequence.KeySignature.A,
'a#': music_pb2.NoteSequence.KeySignature.A_SHARP,
'bb': music_pb2.NoteSequence.KeySignature.B_FLAT,
'b': music_pb2.NoteSequence.KeySignature.B,
}
SHARPS_ORDER = 'FCGDAEB'
FLATS_ORDER = 'BEADGCF'
INFORMATION_FIELD_PATTERN = re.compile(r'([A-Za-z]):\s*(.*)')
def __init__(self, tune_lines):
self._ns = music_pb2.NoteSequence()
# Standard ABC fields.
self._ns.source_info.source_type = (
music_pb2.NoteSequence.SourceInfo.SCORE_BASED)
self._ns.source_info.encoding_type = (
music_pb2.NoteSequence.SourceInfo.ABC)
self._ns.source_info.parser = (
music_pb2.NoteSequence.SourceInfo.MAGENTA_ABC)
self._ns.ticks_per_quarter = constants.STANDARD_PPQ
self._current_time = 0
self._accidentals = ABCTune._sig_to_accidentals(0)
self._bar_accidentals = {}
self._current_unit_note_length = None
self._current_expected_repeats = None
# Default dynamic should be !mf! as per:
# http://abcnotation.com/wiki/abc:standard:v2.1#decorations
self._current_velocity = ABCTune.DECORATION_TO_VELOCITY['!mf!']
self._in_header = True
self._header_tempo_unit = None
self._header_tempo_rate = None
for line in tune_lines:
line = re.sub('%.*$', '', line) # Strip comments.
line = line.strip() # Strip whitespace.
if not line:
continue
# If the lines begins with a letter and a colon, it's an information
# field. Extract it.
info_field_match = ABCTune.INFORMATION_FIELD_PATTERN.match(line)
if info_field_match:
self._parse_information_field(
info_field_match.group(1), info_field_match.group(2))
else:
if self._in_header:
self._set_values_from_header()
self._in_header = False
self._parse_music_code(line)
if self._in_header:
self._set_values_from_header()
self._finalize()
if self._ns.notes:
self._ns.total_time = self._ns.notes[-1].end_time
@property
def note_sequence(self):
return self._ns
@staticmethod
def _sig_to_accidentals(sig):
accidentals = {pitch: 0 for pitch in 'ABCDEFG'}
if sig > 0:
for i in range(sig):
accidentals[ABCTune.SHARPS_ORDER[i]] = 1
elif sig < 0:
for i in range(abs(sig)):
accidentals[ABCTune.FLATS_ORDER[i]] = -1
return accidentals
@property
def _qpm(self):
"""Returns the current QPM."""
if self._ns.tempos:
return self._ns.tempos[-1].qpm
else:
# No QPM has been specified, so will use the default one.
return constants.DEFAULT_QUARTERS_PER_MINUTE
def _set_values_from_header(self):
# Set unit note length. May depend on the current meter, so this has to be
# calculated at the end of the header.
self._set_unit_note_length_from_header()
# Set the tempo if it was specified in the header. May depend on current
# unit note length, so has to be calculated after that is set.
# _header_tempo_unit may be legitimately None, so check _header_tempo_rate.
if self._header_tempo_rate:
self._add_tempo(self._header_tempo_unit, self._header_tempo_rate)
def _set_unit_note_length_from_header(self):
"""Sets the current unit note length.
Should be called immediately after parsing the header.
Raises:
ABCParseError: If multiple time signatures were set in the header.
"""
# http://abcnotation.com/wiki/abc:standard:v2.1#lunit_note_length
if self._current_unit_note_length:
# If it has been set explicitly, leave it as is.
pass
elif not self._ns.time_signatures:
# For free meter, the default unit note length is 1/8.
self._current_unit_note_length = Fraction(1, 8)
else:
# Otherwise, base it on the current meter.
if len(self._ns.time_signatures) != 1:
raise ABCParseError('Multiple time signatures set in header.')
current_ts = self._ns.time_signatures[0]
ratio = current_ts.numerator / current_ts.denominator
if ratio < 0.75:
self._current_unit_note_length = Fraction(1, 16)
else:
self._current_unit_note_length = Fraction(1, 8)
def _add_tempo(self, tempo_unit, tempo_rate):
if tempo_unit is None:
tempo_unit = self._current_unit_note_length
tempo = self._ns.tempos.add()
tempo.time = self._current_time
tempo.qpm = float((tempo_unit / Fraction(1, 4)) * tempo_rate)
def _add_section(self, time):
"""Adds a new section to the NoteSequence.
If the most recently added section is for the same time, a new section will
not be created.
Args:
time: The time at which to create the new section.
Returns:
The id of the newly created section, or None if no new section was
created.
"""
if not self._ns.section_annotations and time > 0:
# We're in a piece with sections, need to add a section marker at the
# beginning of the piece if there isn't one there already.
sa = self._ns.section_annotations.add()
sa.time = 0
sa.section_id = 0
if self._ns.section_annotations:
if self._ns.section_annotations[-1].time == time:
logging.debug('Ignoring duplicate section at time %f', time)
return None
new_id = self._ns.section_annotations[-1].section_id + 1
else:
new_id = 0
sa = self._ns.section_annotations.add()
sa.time = time
sa.section_id = new_id
return new_id
def _finalize(self):
"""Do final cleanup. To be called at the end of the tune."""
self._finalize_repeats()
self._finalize_sections()
def _finalize_repeats(self):
"""Handle any pending repeats."""
# If we're still expecting a repeat at the end of the tune, that's an error
# in the file.
if self._current_expected_repeats:
raise RepeatParseError(
'Expected a repeat at the end of the file, but did not get one.')
def _finalize_sections(self):
"""Handle any pending sections."""
# If a new section was started at the very end of the piece, delete it
# because it will contain no notes and is meaningless.
# This happens if the last line in the piece ends with a :| symbol. A new
# section is set up to handle upcoming notes, but then the end of the piece
# is reached.
if (self._ns.section_annotations and
self._ns.section_annotations[-1].time == self._ns.notes[-1].end_time):
del self._ns.section_annotations[-1]
# Make sure the final section annotation is referenced in a section group.
# If it hasn't been referenced yet, it just needs to be played once.
# This checks that the final section_annotation is referenced in the final
# section_group.
# At this point, all of our section_groups have only 1 section, so this
# logic will need to be updated when we support parts and start creating
# more complex section_groups.
if (self._ns.section_annotations and self._ns.section_groups and
self._ns.section_groups[-1].sections[0].section_id !=
self._ns.section_annotations[-1].section_id):
sg = self._ns.section_groups.add()
sg.sections.add(
section_id=self._ns.section_annotations[-1].section_id)
sg.num_times = 1
def _apply_broken_rhythm(self, broken_rhythm):
"""Applies a broken rhythm symbol to the two most recently added notes."""
# http://abcnotation.com/wiki/abc:standard:v2.1#broken_rhythm
if len(self._ns.notes) < 2:
raise ABCParseError(
'Cannot apply a broken rhythm with fewer than 2 notes')
note1 = self._ns.notes[-2]
note2 = self._ns.notes[-1]
note1_len = note1.end_time - note1.start_time
note2_len = note2.end_time - note2.start_time
if note1_len != note2_len:
raise ABCParseError(
'Cannot apply broken rhythm to two notes of different lengths')
time_adj = note1_len / (2 ** len(broken_rhythm))
if broken_rhythm[0] == '<':
note1.end_time -= time_adj
note2.start_time -= time_adj
elif broken_rhythm[0] == '>':
note1.end_time += time_adj
note2.start_time += time_adj
else:
raise ABCParseError('Could not parse broken rhythm token: {}'.format(
broken_rhythm))
# http://abcnotation.com/wiki/abc:standard:v2.1#pitch
NOTE_PATTERN = re.compile(
r'(__|_|=|\^|\^\^)?([A-Ga-g])([\',]*)(\d*/*\d*)')
# http://abcnotation.com/wiki/abc:standard:v2.1#chords_and_unisons
CHORD_PATTERN = re.compile(r'\[(' + NOTE_PATTERN.pattern + r')+\]')
# http://abcnotation.com/wiki/abc:standard:v2.1#broken_rhythm
BROKEN_RHYTHM_PATTERN = re.compile(r'(<+|>+)')
# http://abcnotation.com/wiki/abc:standard:v2.1#use_of_fields_within_the_tune_body
INLINE_INFORMATION_FIELD_PATTERN = re.compile(r'\[([A-Za-z]):\s*([^\]]+)\]')
# http://abcnotation.com/wiki/abc:standard:v2.1#repeat_bar_symbols
# Pattern for matching variant endings with an associated bar symbol.
BAR_AND_VARIANT_ENDINGS_PATTERN = re.compile(r'(:*)[\[\]|]+\s*([0-9,-]+)')
# Pattern for matching repeat symbols with an associated bar symbol.
BAR_AND_REPEAT_SYMBOLS_PATTERN = re.compile(r'(:*)([\[\]|]+)(:*)')
# Pattern for matching repeat symbols without an associated bar symbol.
REPEAT_SYMBOLS_PATTERN = re.compile(r'(:+)')
# http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols
# http://abcnotation.com/wiki/abc:standard:v2.1#annotations
TEXT_ANNOTATION_PATTERN = re.compile(r'"([^"]*)"')
# http://abcnotation.com/wiki/abc:standard:v2.1#decorations
DECORATION_PATTERN = re.compile(r'[.~HLMOPSTuv]')
# http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs
# Either an opening parenthesis (not followed by a digit, since that indicates
# a tuplet) or a closing parenthesis.
SLUR_PATTERN = re.compile(r'\((?!\d)|\)')
TIE_PATTERN = re.compile(r'-')
# http://abcnotation.com/wiki/abc:standard:v2.1#duplets_triplets_quadruplets_etc
TUPLET_PATTERN = re.compile(r'\(\d')
# http://abcnotation.com/wiki/abc:standard:v2.1#typesetting_line-breaks
LINE_CONTINUATION_PATTERN = re.compile(r'\\$')
def _parse_music_code(self, line):
"""Parse the music code within an ABC file."""
# http://abcnotation.com/wiki/abc:standard:v2.1#the_tune_body
pos = 0
broken_rhythm = None
while pos < len(line):
match = None
for regex in [
ABCTune.NOTE_PATTERN,
ABCTune.CHORD_PATTERN,
ABCTune.BROKEN_RHYTHM_PATTERN,
ABCTune.INLINE_INFORMATION_FIELD_PATTERN,
ABCTune.BAR_AND_VARIANT_ENDINGS_PATTERN,
ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN,
ABCTune.REPEAT_SYMBOLS_PATTERN,
ABCTune.TEXT_ANNOTATION_PATTERN,
ABCTune.DECORATION_PATTERN,
ABCTune.SLUR_PATTERN,
ABCTune.TIE_PATTERN,
ABCTune.TUPLET_PATTERN,
ABCTune.LINE_CONTINUATION_PATTERN]:
match = regex.match(line, pos)
if match:
break
if not match:
if not line[pos].isspace():
raise InvalidCharacterError(
'Unexpected character: [{}]'.format(line[pos].encode('utf-8')))
pos += 1
continue
pos = match.end()
if match.re == ABCTune.NOTE_PATTERN:
note = self._ns.notes.add()
note.velocity = self._current_velocity
note.start_time = self._current_time
note.pitch = ABCTune.ABC_NOTE_TO_MIDI[match.group(2)]
note_name = match.group(2).upper()
# Accidentals
if match.group(1):
pitch_change = 0
for accidental in match.group(1).split():
if accidental == '^':
pitch_change += 1
elif accidental == '_':
pitch_change -= 1
elif accidental == '=':
pass
else:
raise ABCParseError(
'Invalid accidental: {}'.format(accidental))
note.pitch += pitch_change
self._bar_accidentals[note_name] = pitch_change
elif note_name in self._bar_accidentals:
note.pitch += self._bar_accidentals[note_name]
else:
# No accidentals, so modify according to current key.
note.pitch += self._accidentals[note_name]
# Octaves
if match.group(3):
for octave in match.group(3):
if octave == '\'':
note.pitch += 12
elif octave == ',':
note.pitch -= 12
else:
raise ABCParseError('Invalid octave: {}'.format(octave))
if (note.pitch < constants.MIN_MIDI_PITCH or
note.pitch > constants.MAX_MIDI_PITCH):
raise ABCParseError('pitch {} is invalid'.format(note.pitch))
# Note length
length = self._current_unit_note_length
# http://abcnotation.com/wiki/abc:standard:v2.1#note_lengths
if match.group(4):
slash_count = match.group(4).count('/')
if slash_count == len(match.group(4)):
# Handle A// shorthand case.
length /= 2 ** slash_count
elif match.group(4).startswith('/'):
length /= int(match.group(4)[1:])
elif slash_count == 1:
fraction = match.group(4).split('/', 1)
# If no denominator is specified (e.g., "3/"), default to 2.
if not fraction[1]:
fraction[1] = 2
length *= Fraction(int(fraction[0]), int(fraction[1]))
elif slash_count == 0:
length *= int(match.group(4))
else:
raise ABCParseError(
'Could not parse note length: {}'.format(match.group(4)))
# Advance clock based on note length.
self._current_time += (1 / (self._qpm / 60)) * (length / Fraction(1, 4))
note.end_time = self._current_time
if broken_rhythm:
self._apply_broken_rhythm(broken_rhythm)
broken_rhythm = None
elif match.re == ABCTune.CHORD_PATTERN:
raise ChordError('Chords are not supported.')
elif match.re == ABCTune.BROKEN_RHYTHM_PATTERN:
if broken_rhythm:
raise ABCParseError(
'Cannot specify a broken rhythm twice in a row.')
broken_rhythm = match.group(1)
elif match.re == ABCTune.INLINE_INFORMATION_FIELD_PATTERN:
self._parse_information_field(match.group(1), match.group(2))
elif match.re == ABCTune.BAR_AND_VARIANT_ENDINGS_PATTERN:
raise VariantEndingError(
'Variant ending {} is not supported.'.format(match.group(0)))
elif (match.re == ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN or
match.re == ABCTune.REPEAT_SYMBOLS_PATTERN):
if match.re == ABCTune.REPEAT_SYMBOLS_PATTERN:
colon_count = len(match.group(1))
if colon_count % 2 != 0:
raise RepeatParseError(
'Colon-only repeats must be divisible by 2: {}'.format(
match.group(1)))
backward_repeats = forward_repeats = int((colon_count / 2) + 1)
elif match.re == ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN:
# We're in a new bar, so clear the bar-wise accidentals.
self._bar_accidentals.clear()
is_repeat = ':' in match.group(1) or match.group(3)
if not is_repeat:
if len(match.group(2)) >= 2:
# This is a double bar that isn't a repeat.
if not self._current_expected_repeats and self._current_time > 0:
# There was no previous forward repeat symbol.
# Add a new section so that if there is a backward repeat later
# on, it will repeat to this bar.
new_section_id = self._add_section(self._current_time)
if new_section_id is not None:
sg = self._ns.section_groups.add()
sg.sections.add(
section_id=self._ns.section_annotations[-2].section_id)
sg.num_times = 1
# If this isn't a repeat, no additional work to do.
continue
# Count colons on either side.
if match.group(1):
backward_repeats = len(match.group(1)) + 1
else:
backward_repeats = None
if match.group(3):
forward_repeats = len(match.group(3)) + 1
else:
forward_repeats = None
else:
raise ABCParseError('Unexpected regex. Should not happen.')
if (self._current_expected_repeats and
backward_repeats != self._current_expected_repeats):
raise RepeatParseError(
'Mismatched forward/backward repeat symbols. '
'Expected {} but got {}.'.format(
self._current_expected_repeats, backward_repeats))
# A repeat implies the start of a new section, so make one.
new_section_id = self._add_section(self._current_time)
if backward_repeats:
if self._current_time == 0:
raise RepeatParseError(
'Cannot have a backward repeat at time 0')
sg = self._ns.section_groups.add()
sg.sections.add(
section_id=self._ns.section_annotations[-2].section_id)
sg.num_times = backward_repeats
elif self._current_time > 0 and new_section_id is not None:
# There were not backward repeats, but we still want to play the
# previous section once.
# If new_section_id is None (implying that a section at the current
# time was created elsewhere), this is not needed because it should
# have been done when the section was created.
sg = self._ns.section_groups.add()
sg.sections.add(
section_id=self._ns.section_annotations[-2].section_id)
sg.num_times = 1
self._current_expected_repeats = forward_repeats
elif match.re == ABCTune.TEXT_ANNOTATION_PATTERN:
# Text annotation
# http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols
# http://abcnotation.com/wiki/abc:standard:v2.1#annotations
annotation = match.group(1)
ta = self._ns.text_annotations.add()
ta.time = self._current_time
ta.text = annotation
if annotation and annotation[0] in ABCTune.ABC_NOTE_TO_MIDI:
# http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols
ta.annotation_type = (
music_pb2.NoteSequence.TextAnnotation.CHORD_SYMBOL)
else:
ta.annotation_type = (
music_pb2.NoteSequence.TextAnnotation.UNKNOWN)
elif match.re == ABCTune.DECORATION_PATTERN:
# http://abcnotation.com/wiki/abc:standard:v2.1#decorations
# We don't currently do anything with decorations.
pass
elif match.re == ABCTune.SLUR_PATTERN:
# http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs
# We don't currently do anything with slurs.
pass
elif match.re == ABCTune.TIE_PATTERN:
# http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs
# We don't currently do anything with ties.
# TODO(fjord): Ideally, we would extend the duration of the previous
# note to include the duration of the next note.
pass
elif match.re == ABCTune.TUPLET_PATTERN:
raise TupletError('Tuplets are not supported.')
elif match.re == ABCTune.LINE_CONTINUATION_PATTERN:
# http://abcnotation.com/wiki/abc:standard:v2.1#typesetting_line-breaks
# Line continuations are only for typesetting, so we can ignore them.
pass
else:
raise ABCParseError('Unknown regex match!')
# http://abcnotation.com/wiki/abc:standard:v2.1#kkey
KEY_PATTERN = re.compile(
r'([A-G])\s*([#b]?)\s*'
r'((?:(?:maj|ion|min|aeo|mix|dor|phr|lyd|loc|m)[^ ]*)?)',
re.IGNORECASE)
# http://abcnotation.com/wiki/abc:standard:v2.1#kkey
KEY_ACCIDENTALS_PATTERN = re.compile(r'(__|_|=|\^|\^\^)?([A-Ga-g])')
@staticmethod
def parse_key(key):
"""Parse an ABC key string."""
# http://abcnotation.com/wiki/abc:standard:v2.1#kkey
key_match = ABCTune.KEY_PATTERN.match(key)
if not key_match:
raise ABCParseError('Could not parse key: {}'.format(key))
key_components = list(key_match.groups())
# Shorten the mode to be at most 3 letters long.
mode = key_components[2][:3].lower()
# "Minor" and "Aeolian" are special cases that are abbreviated to 'm'.
# "Major" and "Ionian" are special cases that are abbreviated to ''.
if mode in ('min', 'aeo'):
mode = 'm'
elif mode in ('maj', 'ion'):
mode = ''
sig = ABCTune.KEY_TO_SIG[''.join(key_components[0:2] + [mode]).lower()]
proto_key = ABCTune.KEY_TO_PROTO_KEY[''.join(key_components[0:2]).lower()]
if mode == '': # pylint: disable=g-explicit-bool-comparison
proto_mode = music_pb2.NoteSequence.KeySignature.MAJOR
elif mode == 'm':
proto_mode = music_pb2.NoteSequence.KeySignature.MINOR
elif mode == 'mix':
proto_mode = music_pb2.NoteSequence.KeySignature.MIXOLYDIAN
elif mode == 'dor':
proto_mode = music_pb2.NoteSequence.KeySignature.DORIAN
elif mode == 'phr':
proto_mode = music_pb2.NoteSequence.KeySignature.PHRYGIAN
elif mode == 'lyd':
proto_mode = music_pb2.NoteSequence.KeySignature.LYDIAN
elif mode == 'loc':
proto_mode = music_pb2.NoteSequence.KeySignature.LOCRIAN
else:
raise ABCParseError('Unknown mode: {}'.format(mode))
# Match the rest of the string for possible modifications.
pos = key_match.end()
exppos = key[pos:].find('exp')
if exppos != -1:
# Only explicit accidentals will be used.
accidentals = ABCTune._sig_to_accidentals(0)
pos += exppos + 3
else:
accidentals = ABCTune._sig_to_accidentals(sig)
while pos < len(key):
note_match = ABCTune.KEY_ACCIDENTALS_PATTERN.match(key, pos)
if note_match:
pos += len(note_match.group(0))
note = note_match.group(2).upper()
if note_match.group(1):
if note_match.group(1) == '^':
accidentals[note] = 1
elif note_match.group(1) == '_':
accidentals[note] = -1
elif note_match.group(1) == '=':
accidentals[note] = 0
else:
raise ABCParseError(
'Invalid accidental: {}'.format(note_match.group(1)))
else:
pos += 1
return accidentals, proto_key, proto_mode
# http://abcnotation.com/wiki/abc:standard:v2.1#outdated_information_field_syntax
# This syntax is deprecated but must still be supported.
TEMPO_DEPRECATED_PATTERN = re.compile(r'C?\s*=?\s*(\d+)$')
# http://abcnotation.com/wiki/abc:standard:v2.1#qtempo
TEMPO_PATTERN = re.compile(r'(?:"[^"]*")?\s*((?:\d+/\d+\s*)+)\s*=\s*(\d+)')
TEMPO_PATTERN_STRING_ONLY = re.compile(r'"([^"]*)"$')
def _parse_information_field(self, field_name, field_content):
"""Parses information field."""
# http://abcnotation.com/wiki/abc:standard:v2.1#information_fields
if field_name == 'A':
pass
elif field_name == 'B':
pass
elif field_name == 'C':
# Composer
# http://abcnotation.com/wiki/abc:standard:v2.1#ccomposer
self._ns.sequence_metadata.composers.append(field_content)
# The first composer will be set as the primary artist.
if not self._ns.sequence_metadata.artist:
self._ns.sequence_metadata.artist = field_content
elif field_name == 'D':
pass
elif field_name == 'F':
pass
elif field_name == 'G':
pass
elif field_name == 'H':
pass
elif field_name == 'I':
pass
elif field_name == 'K':
# Key
# http://abcnotation.com/wiki/abc:standard:v2.1#kkey
accidentals, proto_key, proto_mode = ABCTune.parse_key(field_content)
self._accidentals = accidentals
ks = self._ns.key_signatures.add()
ks.key = proto_key
ks.mode = proto_mode
ks.time = self._current_time
elif field_name == 'L':
# Unit note length
# http://abcnotation.com/wiki/abc:standard:v2.1#lunit_note_length
length = field_content.split('/', 1)
# Handle the case of L:1 being equivalent to L:1/1
if len(length) < 2:
length.append('1')
try:
numerator = int(length[0])
denominator = int(length[1])
except ValueError as e:
raise ABCParseError(
e, 'Could not parse unit note length: {}'.format(field_content))
self._current_unit_note_length = Fraction(numerator, denominator)
elif field_name == 'M':
# Meter
# http://abcnotation.com/wiki/abc:standard:v2.1#mmeter
if field_content.upper() == 'C':
ts = self._ns.time_signatures.add()
ts.numerator = 4
ts.denominator = 4
ts.time = self._current_time
elif field_content.upper() == 'C|':
ts = self._ns.time_signatures.add()
ts.numerator = 2
ts.denominator = 2
ts.time = self._current_time
elif field_content.lower() == 'none':
pass
else:
timesig = field_content.split('/', 1)
if len(timesig) != 2:
raise ABCParseError('Could not parse meter: {}'.format(field_content))
ts = self._ns.time_signatures.add()
ts.time = self._current_time
try:
ts.numerator = int(timesig[0])
ts.denominator = int(timesig[1])
except ValueError as e:
raise ABCParseError(
e, 'Could not parse meter: {}'.format(field_content))
elif field_name == 'm':
pass
elif field_name == 'N':
pass
elif field_name == 'O':
pass
elif field_name == 'P':
# TODO(fjord): implement part parsing.
raise PartError('ABC parts are not yet supported.')
elif field_name == 'Q':
# Tempo
# http://abcnotation.com/wiki/abc:standard:v2.1#qtempo
tempo_match = ABCTune.TEMPO_PATTERN.match(field_content)
deprecated_tempo_match = ABCTune.TEMPO_DEPRECATED_PATTERN.match(
field_content)
tempo_string_only_match = ABCTune.TEMPO_PATTERN_STRING_ONLY.match(
field_content)
if tempo_match:
tempo_rate = int(tempo_match.group(2))
tempo_unit = Fraction(0)
for beat in tempo_match.group(1).split():
tempo_unit += Fraction(beat)
elif deprecated_tempo_match:
# http://abcnotation.com/wiki/abc:standard:v2.1#outdated_information_field_syntax
# In the deprecated syntax, the tempo is interpreted based on the unit
# note length, which is potentially dependent on the current meter.
# Set tempo_unit to None for now, and the current unit note length will
# be filled in later.
tempo_unit = None
tempo_rate = int(deprecated_tempo_match.group(1))
elif tempo_string_only_match:
logging.warning('Ignoring string-only tempo marking: %s', field_content)
return
else:
raise ABCParseError('Could not parse tempo: {}'.format(field_content))
if self._in_header:
# If we're in the header, save these until we've finished parsing the
# header. The deprecated syntax relies on the unit note length and
# meter, which may not be set yet. At the end of the header, we'll fill
# in the necessary information and add these.
self._header_tempo_unit = tempo_unit
self._header_tempo_rate = tempo_rate
else:
self._add_tempo(tempo_unit, tempo_rate)
elif field_name == 'R':
pass
elif field_name == 'r':
pass
elif field_name == 'S':
pass
elif field_name == 's':
pass
elif field_name == 'T':
# Title
# http://abcnotation.com/wiki/abc:standard:v2.1#ttune_title
if not self._in_header:
# TODO(fjord): Non-header titles are used to name parts of tunes, but
# NoteSequence doesn't currently have any place to put that information.
logging.warning('Ignoring non-header title: %s', field_content)
return
# If there are multiple titles, separate them with semicolons.
if self._ns.sequence_metadata.title:
self._ns.sequence_metadata.title += '; ' + field_content
else:
self._ns.sequence_metadata.title = field_content
elif field_name == 'U':
pass
elif field_name == 'V':
raise MultiVoiceError('Multi-voice files are not currently supported.')
elif field_name == 'W':
pass
elif field_name == 'w':
pass
elif field_name == 'X':
# Reference number
# http://abcnotation.com/wiki/abc:standard:v2.1#xreference_number
self._ns.reference_number = int(field_content)
elif field_name == 'Z':
pass
else:
logging.warning(
'Unknown field name %s with content %s', field_name, field_content)Functions
def parse_abc_tunebook(tunebook)-
Parse an ABC Tunebook string.
Args
tunebook- The ABC tunebook as a string.
Returns
tunes- A dictionary of reference number to NoteSequence of parsed ABC tunes.
exceptions- A list of exceptions for tunes that could not be parsed.
Raises
DuplicateReferenceNumberError- If the same reference number appears more than once in the tunebook.
Expand source code
def parse_abc_tunebook(tunebook): """Parse an ABC Tunebook string. Args: tunebook: The ABC tunebook as a string. Returns: tunes: A dictionary of reference number to NoteSequence of parsed ABC tunes. exceptions: A list of exceptions for tunes that could not be parsed. Raises: DuplicateReferenceNumberError: If the same reference number appears more than once in the tunebook. """ # Split tunebook into sections based on empty lines. sections = [] current_lines = [] for line in tunebook.splitlines(): line = line.strip() if not line: if current_lines: sections.append(current_lines) current_lines = [] else: current_lines.append(line) if current_lines: sections.append(current_lines) # If there are multiple sections, the first one may be a header. # The first section is a header if it does not contain an X information field. header = [] if len(sections) > 1 and not any( line.startswith('X:') for line in sections[0]): header = sections.pop(0) tunes = {} exceptions = [] for tune in sections: try: # The header sets default values for each tune, so prepend it to every # tune that is being parsed. abc_tune = ABCTune(header + tune) except ABCParseError as e: exceptions.append(e) else: ns = abc_tune.note_sequence if ns.reference_number in tunes: raise DuplicateReferenceNumberError( 'ABC Reference number {} appears more than once in this ' 'tunebook'.format(ns.reference_number)) tunes[ns.reference_number] = ns return tunes, exceptions def parse_abc_tunebook_file(filename)-
Parse an ABC Tunebook file.
Args
filename- File path to an ABC tunebook.
Returns
tunes- A dictionary of reference number to NoteSequence of parsed ABC tunes.
exceptions- A list of exceptions for tunes that could not be parsed.
Raises
DuplicateReferenceNumberError- If the same reference number appears more than once in the tunebook.
Expand source code
def parse_abc_tunebook_file(filename): """Parse an ABC Tunebook file. Args: filename: File path to an ABC tunebook. Returns: tunes: A dictionary of reference number to NoteSequence of parsed ABC tunes. exceptions: A list of exceptions for tunes that could not be parsed. Raises: DuplicateReferenceNumberError: If the same reference number appears more than once in the tunebook. """ # 'r' mode will decode the file as utf-8 in py3. return parse_abc_tunebook(open(filename, 'r').read())
Classes
class ABCParseError (*args, **kwargs)-
Exception thrown when ABC contents cannot be parsed.
Expand source code
class ABCParseError(Exception): """Exception thrown when ABC contents cannot be parsed.""" passAncestors
- builtins.Exception
- builtins.BaseException
Subclasses
class ABCTune (tune_lines)-
Class for parsing an individual ABC tune.
Expand source code
class ABCTune(object): """Class for parsing an individual ABC tune.""" # http://abcnotation.com/wiki/abc:standard:v2.1#decorations DECORATION_TO_VELOCITY = { '!pppp!': 30, '!ppp!': 30, '!pp!': 45, '!p!': 60, '!mp!': 75, '!mf!': 90, '!f!': 105, '!ff!': 120, '!fff!': 127, '!ffff!': 127, } # http://abcnotation.com/wiki/abc:standard:v2.1#pitch ABC_NOTE_TO_MIDI = { 'C': 60, 'D': 62, 'E': 64, 'F': 65, 'G': 67, 'A': 69, 'B': 71, 'c': 72, 'd': 74, 'e': 76, 'f': 77, 'g': 79, 'a': 81, 'b': 83, } # http://abcnotation.com/wiki/abc:standard:v2.1#kkey SIG_TO_KEYS = { 7: ['C#', 'A#m', 'G#Mix', 'D#Dor', 'E#Phr', 'F#Lyd', 'B#Loc'], 6: ['F#', 'D#m', 'C#Mix', 'G#Dor', 'A#Phr', 'BLyd', 'E#Loc'], 5: ['B', 'G#m', 'F#Mix', 'C#Dor', 'D#Phr', 'ELyd', 'A#Loc'], 4: ['E', 'C#m', 'BMix', 'F#Dor', 'G#Phr', 'ALyd', 'D#Loc'], 3: ['A', 'F#m', 'EMix', 'BDor', 'C#Phr', 'DLyd', 'G#Loc'], 2: ['D', 'Bm', 'AMix', 'EDor', 'F#Phr', 'GLyd', 'C#Loc'], 1: ['G', 'Em', 'DMix', 'ADor', 'BPhr', 'CLyd', 'F#Loc'], 0: ['C', 'Am', 'GMix', 'DDor', 'EPhr', 'FLyd', 'BLoc'], -1: ['F', 'Dm', 'CMix', 'GDor', 'APhr', 'BbLyd', 'ELoc'], -2: ['Bb', 'Gm', 'FMix', 'CDor', 'DPhr', 'EbLyd', 'ALoc'], -3: ['Eb', 'Cm', 'BbMix', 'FDor', 'GPhr', 'AbLyd', 'DLoc'], -4: ['Ab', 'Fm', 'EbMix', 'BbDor', 'CPhr', 'DbLyd', 'GLoc'], -5: ['Db', 'Bbm', 'AbMix', 'EbDor', 'FPhr', 'GbLyd', 'CLoc'], -6: ['Gb', 'Ebm', 'DbMix', 'AbDor', 'BbPhr', 'CbLyd', 'FLoc'], -7: ['Cb', 'Abm', 'GbMix', 'DbDor', 'EbPhr', 'FbLyd', 'BbLoc'], } KEY_TO_SIG = {} for sig, keys in SIG_TO_KEYS.items(): for key in keys: KEY_TO_SIG[key.lower()] = sig KEY_TO_PROTO_KEY = { 'c': music_pb2.NoteSequence.KeySignature.C, 'c#': music_pb2.NoteSequence.KeySignature.C_SHARP, 'db': music_pb2.NoteSequence.KeySignature.D_FLAT, 'd': music_pb2.NoteSequence.KeySignature.D, 'd#': music_pb2.NoteSequence.KeySignature.D_SHARP, 'eb': music_pb2.NoteSequence.KeySignature.E_FLAT, 'e': music_pb2.NoteSequence.KeySignature.E, 'f': music_pb2.NoteSequence.KeySignature.F, 'f#': music_pb2.NoteSequence.KeySignature.F_SHARP, 'gb': music_pb2.NoteSequence.KeySignature.G_FLAT, 'g': music_pb2.NoteSequence.KeySignature.G, 'g#': music_pb2.NoteSequence.KeySignature.G_SHARP, 'ab': music_pb2.NoteSequence.KeySignature.A_FLAT, 'a': music_pb2.NoteSequence.KeySignature.A, 'a#': music_pb2.NoteSequence.KeySignature.A_SHARP, 'bb': music_pb2.NoteSequence.KeySignature.B_FLAT, 'b': music_pb2.NoteSequence.KeySignature.B, } SHARPS_ORDER = 'FCGDAEB' FLATS_ORDER = 'BEADGCF' INFORMATION_FIELD_PATTERN = re.compile(r'([A-Za-z]):\s*(.*)') def __init__(self, tune_lines): self._ns = music_pb2.NoteSequence() # Standard ABC fields. self._ns.source_info.source_type = ( music_pb2.NoteSequence.SourceInfo.SCORE_BASED) self._ns.source_info.encoding_type = ( music_pb2.NoteSequence.SourceInfo.ABC) self._ns.source_info.parser = ( music_pb2.NoteSequence.SourceInfo.MAGENTA_ABC) self._ns.ticks_per_quarter = constants.STANDARD_PPQ self._current_time = 0 self._accidentals = ABCTune._sig_to_accidentals(0) self._bar_accidentals = {} self._current_unit_note_length = None self._current_expected_repeats = None # Default dynamic should be !mf! as per: # http://abcnotation.com/wiki/abc:standard:v2.1#decorations self._current_velocity = ABCTune.DECORATION_TO_VELOCITY['!mf!'] self._in_header = True self._header_tempo_unit = None self._header_tempo_rate = None for line in tune_lines: line = re.sub('%.*$', '', line) # Strip comments. line = line.strip() # Strip whitespace. if not line: continue # If the lines begins with a letter and a colon, it's an information # field. Extract it. info_field_match = ABCTune.INFORMATION_FIELD_PATTERN.match(line) if info_field_match: self._parse_information_field( info_field_match.group(1), info_field_match.group(2)) else: if self._in_header: self._set_values_from_header() self._in_header = False self._parse_music_code(line) if self._in_header: self._set_values_from_header() self._finalize() if self._ns.notes: self._ns.total_time = self._ns.notes[-1].end_time @property def note_sequence(self): return self._ns @staticmethod def _sig_to_accidentals(sig): accidentals = {pitch: 0 for pitch in 'ABCDEFG'} if sig > 0: for i in range(sig): accidentals[ABCTune.SHARPS_ORDER[i]] = 1 elif sig < 0: for i in range(abs(sig)): accidentals[ABCTune.FLATS_ORDER[i]] = -1 return accidentals @property def _qpm(self): """Returns the current QPM.""" if self._ns.tempos: return self._ns.tempos[-1].qpm else: # No QPM has been specified, so will use the default one. return constants.DEFAULT_QUARTERS_PER_MINUTE def _set_values_from_header(self): # Set unit note length. May depend on the current meter, so this has to be # calculated at the end of the header. self._set_unit_note_length_from_header() # Set the tempo if it was specified in the header. May depend on current # unit note length, so has to be calculated after that is set. # _header_tempo_unit may be legitimately None, so check _header_tempo_rate. if self._header_tempo_rate: self._add_tempo(self._header_tempo_unit, self._header_tempo_rate) def _set_unit_note_length_from_header(self): """Sets the current unit note length. Should be called immediately after parsing the header. Raises: ABCParseError: If multiple time signatures were set in the header. """ # http://abcnotation.com/wiki/abc:standard:v2.1#lunit_note_length if self._current_unit_note_length: # If it has been set explicitly, leave it as is. pass elif not self._ns.time_signatures: # For free meter, the default unit note length is 1/8. self._current_unit_note_length = Fraction(1, 8) else: # Otherwise, base it on the current meter. if len(self._ns.time_signatures) != 1: raise ABCParseError('Multiple time signatures set in header.') current_ts = self._ns.time_signatures[0] ratio = current_ts.numerator / current_ts.denominator if ratio < 0.75: self._current_unit_note_length = Fraction(1, 16) else: self._current_unit_note_length = Fraction(1, 8) def _add_tempo(self, tempo_unit, tempo_rate): if tempo_unit is None: tempo_unit = self._current_unit_note_length tempo = self._ns.tempos.add() tempo.time = self._current_time tempo.qpm = float((tempo_unit / Fraction(1, 4)) * tempo_rate) def _add_section(self, time): """Adds a new section to the NoteSequence. If the most recently added section is for the same time, a new section will not be created. Args: time: The time at which to create the new section. Returns: The id of the newly created section, or None if no new section was created. """ if not self._ns.section_annotations and time > 0: # We're in a piece with sections, need to add a section marker at the # beginning of the piece if there isn't one there already. sa = self._ns.section_annotations.add() sa.time = 0 sa.section_id = 0 if self._ns.section_annotations: if self._ns.section_annotations[-1].time == time: logging.debug('Ignoring duplicate section at time %f', time) return None new_id = self._ns.section_annotations[-1].section_id + 1 else: new_id = 0 sa = self._ns.section_annotations.add() sa.time = time sa.section_id = new_id return new_id def _finalize(self): """Do final cleanup. To be called at the end of the tune.""" self._finalize_repeats() self._finalize_sections() def _finalize_repeats(self): """Handle any pending repeats.""" # If we're still expecting a repeat at the end of the tune, that's an error # in the file. if self._current_expected_repeats: raise RepeatParseError( 'Expected a repeat at the end of the file, but did not get one.') def _finalize_sections(self): """Handle any pending sections.""" # If a new section was started at the very end of the piece, delete it # because it will contain no notes and is meaningless. # This happens if the last line in the piece ends with a :| symbol. A new # section is set up to handle upcoming notes, but then the end of the piece # is reached. if (self._ns.section_annotations and self._ns.section_annotations[-1].time == self._ns.notes[-1].end_time): del self._ns.section_annotations[-1] # Make sure the final section annotation is referenced in a section group. # If it hasn't been referenced yet, it just needs to be played once. # This checks that the final section_annotation is referenced in the final # section_group. # At this point, all of our section_groups have only 1 section, so this # logic will need to be updated when we support parts and start creating # more complex section_groups. if (self._ns.section_annotations and self._ns.section_groups and self._ns.section_groups[-1].sections[0].section_id != self._ns.section_annotations[-1].section_id): sg = self._ns.section_groups.add() sg.sections.add( section_id=self._ns.section_annotations[-1].section_id) sg.num_times = 1 def _apply_broken_rhythm(self, broken_rhythm): """Applies a broken rhythm symbol to the two most recently added notes.""" # http://abcnotation.com/wiki/abc:standard:v2.1#broken_rhythm if len(self._ns.notes) < 2: raise ABCParseError( 'Cannot apply a broken rhythm with fewer than 2 notes') note1 = self._ns.notes[-2] note2 = self._ns.notes[-1] note1_len = note1.end_time - note1.start_time note2_len = note2.end_time - note2.start_time if note1_len != note2_len: raise ABCParseError( 'Cannot apply broken rhythm to two notes of different lengths') time_adj = note1_len / (2 ** len(broken_rhythm)) if broken_rhythm[0] == '<': note1.end_time -= time_adj note2.start_time -= time_adj elif broken_rhythm[0] == '>': note1.end_time += time_adj note2.start_time += time_adj else: raise ABCParseError('Could not parse broken rhythm token: {}'.format( broken_rhythm)) # http://abcnotation.com/wiki/abc:standard:v2.1#pitch NOTE_PATTERN = re.compile( r'(__|_|=|\^|\^\^)?([A-Ga-g])([\',]*)(\d*/*\d*)') # http://abcnotation.com/wiki/abc:standard:v2.1#chords_and_unisons CHORD_PATTERN = re.compile(r'\[(' + NOTE_PATTERN.pattern + r')+\]') # http://abcnotation.com/wiki/abc:standard:v2.1#broken_rhythm BROKEN_RHYTHM_PATTERN = re.compile(r'(<+|>+)') # http://abcnotation.com/wiki/abc:standard:v2.1#use_of_fields_within_the_tune_body INLINE_INFORMATION_FIELD_PATTERN = re.compile(r'\[([A-Za-z]):\s*([^\]]+)\]') # http://abcnotation.com/wiki/abc:standard:v2.1#repeat_bar_symbols # Pattern for matching variant endings with an associated bar symbol. BAR_AND_VARIANT_ENDINGS_PATTERN = re.compile(r'(:*)[\[\]|]+\s*([0-9,-]+)') # Pattern for matching repeat symbols with an associated bar symbol. BAR_AND_REPEAT_SYMBOLS_PATTERN = re.compile(r'(:*)([\[\]|]+)(:*)') # Pattern for matching repeat symbols without an associated bar symbol. REPEAT_SYMBOLS_PATTERN = re.compile(r'(:+)') # http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols # http://abcnotation.com/wiki/abc:standard:v2.1#annotations TEXT_ANNOTATION_PATTERN = re.compile(r'"([^"]*)"') # http://abcnotation.com/wiki/abc:standard:v2.1#decorations DECORATION_PATTERN = re.compile(r'[.~HLMOPSTuv]') # http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs # Either an opening parenthesis (not followed by a digit, since that indicates # a tuplet) or a closing parenthesis. SLUR_PATTERN = re.compile(r'\((?!\d)|\)') TIE_PATTERN = re.compile(r'-') # http://abcnotation.com/wiki/abc:standard:v2.1#duplets_triplets_quadruplets_etc TUPLET_PATTERN = re.compile(r'\(\d') # http://abcnotation.com/wiki/abc:standard:v2.1#typesetting_line-breaks LINE_CONTINUATION_PATTERN = re.compile(r'\\$') def _parse_music_code(self, line): """Parse the music code within an ABC file.""" # http://abcnotation.com/wiki/abc:standard:v2.1#the_tune_body pos = 0 broken_rhythm = None while pos < len(line): match = None for regex in [ ABCTune.NOTE_PATTERN, ABCTune.CHORD_PATTERN, ABCTune.BROKEN_RHYTHM_PATTERN, ABCTune.INLINE_INFORMATION_FIELD_PATTERN, ABCTune.BAR_AND_VARIANT_ENDINGS_PATTERN, ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN, ABCTune.REPEAT_SYMBOLS_PATTERN, ABCTune.TEXT_ANNOTATION_PATTERN, ABCTune.DECORATION_PATTERN, ABCTune.SLUR_PATTERN, ABCTune.TIE_PATTERN, ABCTune.TUPLET_PATTERN, ABCTune.LINE_CONTINUATION_PATTERN]: match = regex.match(line, pos) if match: break if not match: if not line[pos].isspace(): raise InvalidCharacterError( 'Unexpected character: [{}]'.format(line[pos].encode('utf-8'))) pos += 1 continue pos = match.end() if match.re == ABCTune.NOTE_PATTERN: note = self._ns.notes.add() note.velocity = self._current_velocity note.start_time = self._current_time note.pitch = ABCTune.ABC_NOTE_TO_MIDI[match.group(2)] note_name = match.group(2).upper() # Accidentals if match.group(1): pitch_change = 0 for accidental in match.group(1).split(): if accidental == '^': pitch_change += 1 elif accidental == '_': pitch_change -= 1 elif accidental == '=': pass else: raise ABCParseError( 'Invalid accidental: {}'.format(accidental)) note.pitch += pitch_change self._bar_accidentals[note_name] = pitch_change elif note_name in self._bar_accidentals: note.pitch += self._bar_accidentals[note_name] else: # No accidentals, so modify according to current key. note.pitch += self._accidentals[note_name] # Octaves if match.group(3): for octave in match.group(3): if octave == '\'': note.pitch += 12 elif octave == ',': note.pitch -= 12 else: raise ABCParseError('Invalid octave: {}'.format(octave)) if (note.pitch < constants.MIN_MIDI_PITCH or note.pitch > constants.MAX_MIDI_PITCH): raise ABCParseError('pitch {} is invalid'.format(note.pitch)) # Note length length = self._current_unit_note_length # http://abcnotation.com/wiki/abc:standard:v2.1#note_lengths if match.group(4): slash_count = match.group(4).count('/') if slash_count == len(match.group(4)): # Handle A// shorthand case. length /= 2 ** slash_count elif match.group(4).startswith('/'): length /= int(match.group(4)[1:]) elif slash_count == 1: fraction = match.group(4).split('/', 1) # If no denominator is specified (e.g., "3/"), default to 2. if not fraction[1]: fraction[1] = 2 length *= Fraction(int(fraction[0]), int(fraction[1])) elif slash_count == 0: length *= int(match.group(4)) else: raise ABCParseError( 'Could not parse note length: {}'.format(match.group(4))) # Advance clock based on note length. self._current_time += (1 / (self._qpm / 60)) * (length / Fraction(1, 4)) note.end_time = self._current_time if broken_rhythm: self._apply_broken_rhythm(broken_rhythm) broken_rhythm = None elif match.re == ABCTune.CHORD_PATTERN: raise ChordError('Chords are not supported.') elif match.re == ABCTune.BROKEN_RHYTHM_PATTERN: if broken_rhythm: raise ABCParseError( 'Cannot specify a broken rhythm twice in a row.') broken_rhythm = match.group(1) elif match.re == ABCTune.INLINE_INFORMATION_FIELD_PATTERN: self._parse_information_field(match.group(1), match.group(2)) elif match.re == ABCTune.BAR_AND_VARIANT_ENDINGS_PATTERN: raise VariantEndingError( 'Variant ending {} is not supported.'.format(match.group(0))) elif (match.re == ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN or match.re == ABCTune.REPEAT_SYMBOLS_PATTERN): if match.re == ABCTune.REPEAT_SYMBOLS_PATTERN: colon_count = len(match.group(1)) if colon_count % 2 != 0: raise RepeatParseError( 'Colon-only repeats must be divisible by 2: {}'.format( match.group(1))) backward_repeats = forward_repeats = int((colon_count / 2) + 1) elif match.re == ABCTune.BAR_AND_REPEAT_SYMBOLS_PATTERN: # We're in a new bar, so clear the bar-wise accidentals. self._bar_accidentals.clear() is_repeat = ':' in match.group(1) or match.group(3) if not is_repeat: if len(match.group(2)) >= 2: # This is a double bar that isn't a repeat. if not self._current_expected_repeats and self._current_time > 0: # There was no previous forward repeat symbol. # Add a new section so that if there is a backward repeat later # on, it will repeat to this bar. new_section_id = self._add_section(self._current_time) if new_section_id is not None: sg = self._ns.section_groups.add() sg.sections.add( section_id=self._ns.section_annotations[-2].section_id) sg.num_times = 1 # If this isn't a repeat, no additional work to do. continue # Count colons on either side. if match.group(1): backward_repeats = len(match.group(1)) + 1 else: backward_repeats = None if match.group(3): forward_repeats = len(match.group(3)) + 1 else: forward_repeats = None else: raise ABCParseError('Unexpected regex. Should not happen.') if (self._current_expected_repeats and backward_repeats != self._current_expected_repeats): raise RepeatParseError( 'Mismatched forward/backward repeat symbols. ' 'Expected {} but got {}.'.format( self._current_expected_repeats, backward_repeats)) # A repeat implies the start of a new section, so make one. new_section_id = self._add_section(self._current_time) if backward_repeats: if self._current_time == 0: raise RepeatParseError( 'Cannot have a backward repeat at time 0') sg = self._ns.section_groups.add() sg.sections.add( section_id=self._ns.section_annotations[-2].section_id) sg.num_times = backward_repeats elif self._current_time > 0 and new_section_id is not None: # There were not backward repeats, but we still want to play the # previous section once. # If new_section_id is None (implying that a section at the current # time was created elsewhere), this is not needed because it should # have been done when the section was created. sg = self._ns.section_groups.add() sg.sections.add( section_id=self._ns.section_annotations[-2].section_id) sg.num_times = 1 self._current_expected_repeats = forward_repeats elif match.re == ABCTune.TEXT_ANNOTATION_PATTERN: # Text annotation # http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols # http://abcnotation.com/wiki/abc:standard:v2.1#annotations annotation = match.group(1) ta = self._ns.text_annotations.add() ta.time = self._current_time ta.text = annotation if annotation and annotation[0] in ABCTune.ABC_NOTE_TO_MIDI: # http://abcnotation.com/wiki/abc:standard:v2.1#chord_symbols ta.annotation_type = ( music_pb2.NoteSequence.TextAnnotation.CHORD_SYMBOL) else: ta.annotation_type = ( music_pb2.NoteSequence.TextAnnotation.UNKNOWN) elif match.re == ABCTune.DECORATION_PATTERN: # http://abcnotation.com/wiki/abc:standard:v2.1#decorations # We don't currently do anything with decorations. pass elif match.re == ABCTune.SLUR_PATTERN: # http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs # We don't currently do anything with slurs. pass elif match.re == ABCTune.TIE_PATTERN: # http://abcnotation.com/wiki/abc:standard:v2.1#ties_and_slurs # We don't currently do anything with ties. # TODO(fjord): Ideally, we would extend the duration of the previous # note to include the duration of the next note. pass elif match.re == ABCTune.TUPLET_PATTERN: raise TupletError('Tuplets are not supported.') elif match.re == ABCTune.LINE_CONTINUATION_PATTERN: # http://abcnotation.com/wiki/abc:standard:v2.1#typesetting_line-breaks # Line continuations are only for typesetting, so we can ignore them. pass else: raise ABCParseError('Unknown regex match!') # http://abcnotation.com/wiki/abc:standard:v2.1#kkey KEY_PATTERN = re.compile( r'([A-G])\s*([#b]?)\s*' r'((?:(?:maj|ion|min|aeo|mix|dor|phr|lyd|loc|m)[^ ]*)?)', re.IGNORECASE) # http://abcnotation.com/wiki/abc:standard:v2.1#kkey KEY_ACCIDENTALS_PATTERN = re.compile(r'(__|_|=|\^|\^\^)?([A-Ga-g])') @staticmethod def parse_key(key): """Parse an ABC key string.""" # http://abcnotation.com/wiki/abc:standard:v2.1#kkey key_match = ABCTune.KEY_PATTERN.match(key) if not key_match: raise ABCParseError('Could not parse key: {}'.format(key)) key_components = list(key_match.groups()) # Shorten the mode to be at most 3 letters long. mode = key_components[2][:3].lower() # "Minor" and "Aeolian" are special cases that are abbreviated to 'm'. # "Major" and "Ionian" are special cases that are abbreviated to ''. if mode in ('min', 'aeo'): mode = 'm' elif mode in ('maj', 'ion'): mode = '' sig = ABCTune.KEY_TO_SIG[''.join(key_components[0:2] + [mode]).lower()] proto_key = ABCTune.KEY_TO_PROTO_KEY[''.join(key_components[0:2]).lower()] if mode == '': # pylint: disable=g-explicit-bool-comparison proto_mode = music_pb2.NoteSequence.KeySignature.MAJOR elif mode == 'm': proto_mode = music_pb2.NoteSequence.KeySignature.MINOR elif mode == 'mix': proto_mode = music_pb2.NoteSequence.KeySignature.MIXOLYDIAN elif mode == 'dor': proto_mode = music_pb2.NoteSequence.KeySignature.DORIAN elif mode == 'phr': proto_mode = music_pb2.NoteSequence.KeySignature.PHRYGIAN elif mode == 'lyd': proto_mode = music_pb2.NoteSequence.KeySignature.LYDIAN elif mode == 'loc': proto_mode = music_pb2.NoteSequence.KeySignature.LOCRIAN else: raise ABCParseError('Unknown mode: {}'.format(mode)) # Match the rest of the string for possible modifications. pos = key_match.end() exppos = key[pos:].find('exp') if exppos != -1: # Only explicit accidentals will be used. accidentals = ABCTune._sig_to_accidentals(0) pos += exppos + 3 else: accidentals = ABCTune._sig_to_accidentals(sig) while pos < len(key): note_match = ABCTune.KEY_ACCIDENTALS_PATTERN.match(key, pos) if note_match: pos += len(note_match.group(0)) note = note_match.group(2).upper() if note_match.group(1): if note_match.group(1) == '^': accidentals[note] = 1 elif note_match.group(1) == '_': accidentals[note] = -1 elif note_match.group(1) == '=': accidentals[note] = 0 else: raise ABCParseError( 'Invalid accidental: {}'.format(note_match.group(1))) else: pos += 1 return accidentals, proto_key, proto_mode # http://abcnotation.com/wiki/abc:standard:v2.1#outdated_information_field_syntax # This syntax is deprecated but must still be supported. TEMPO_DEPRECATED_PATTERN = re.compile(r'C?\s*=?\s*(\d+)$') # http://abcnotation.com/wiki/abc:standard:v2.1#qtempo TEMPO_PATTERN = re.compile(r'(?:"[^"]*")?\s*((?:\d+/\d+\s*)+)\s*=\s*(\d+)') TEMPO_PATTERN_STRING_ONLY = re.compile(r'"([^"]*)"$') def _parse_information_field(self, field_name, field_content): """Parses information field.""" # http://abcnotation.com/wiki/abc:standard:v2.1#information_fields if field_name == 'A': pass elif field_name == 'B': pass elif field_name == 'C': # Composer # http://abcnotation.com/wiki/abc:standard:v2.1#ccomposer self._ns.sequence_metadata.composers.append(field_content) # The first composer will be set as the primary artist. if not self._ns.sequence_metadata.artist: self._ns.sequence_metadata.artist = field_content elif field_name == 'D': pass elif field_name == 'F': pass elif field_name == 'G': pass elif field_name == 'H': pass elif field_name == 'I': pass elif field_name == 'K': # Key # http://abcnotation.com/wiki/abc:standard:v2.1#kkey accidentals, proto_key, proto_mode = ABCTune.parse_key(field_content) self._accidentals = accidentals ks = self._ns.key_signatures.add() ks.key = proto_key ks.mode = proto_mode ks.time = self._current_time elif field_name == 'L': # Unit note length # http://abcnotation.com/wiki/abc:standard:v2.1#lunit_note_length length = field_content.split('/', 1) # Handle the case of L:1 being equivalent to L:1/1 if len(length) < 2: length.append('1') try: numerator = int(length[0]) denominator = int(length[1]) except ValueError as e: raise ABCParseError( e, 'Could not parse unit note length: {}'.format(field_content)) self._current_unit_note_length = Fraction(numerator, denominator) elif field_name == 'M': # Meter # http://abcnotation.com/wiki/abc:standard:v2.1#mmeter if field_content.upper() == 'C': ts = self._ns.time_signatures.add() ts.numerator = 4 ts.denominator = 4 ts.time = self._current_time elif field_content.upper() == 'C|': ts = self._ns.time_signatures.add() ts.numerator = 2 ts.denominator = 2 ts.time = self._current_time elif field_content.lower() == 'none': pass else: timesig = field_content.split('/', 1) if len(timesig) != 2: raise ABCParseError('Could not parse meter: {}'.format(field_content)) ts = self._ns.time_signatures.add() ts.time = self._current_time try: ts.numerator = int(timesig[0]) ts.denominator = int(timesig[1]) except ValueError as e: raise ABCParseError( e, 'Could not parse meter: {}'.format(field_content)) elif field_name == 'm': pass elif field_name == 'N': pass elif field_name == 'O': pass elif field_name == 'P': # TODO(fjord): implement part parsing. raise PartError('ABC parts are not yet supported.') elif field_name == 'Q': # Tempo # http://abcnotation.com/wiki/abc:standard:v2.1#qtempo tempo_match = ABCTune.TEMPO_PATTERN.match(field_content) deprecated_tempo_match = ABCTune.TEMPO_DEPRECATED_PATTERN.match( field_content) tempo_string_only_match = ABCTune.TEMPO_PATTERN_STRING_ONLY.match( field_content) if tempo_match: tempo_rate = int(tempo_match.group(2)) tempo_unit = Fraction(0) for beat in tempo_match.group(1).split(): tempo_unit += Fraction(beat) elif deprecated_tempo_match: # http://abcnotation.com/wiki/abc:standard:v2.1#outdated_information_field_syntax # In the deprecated syntax, the tempo is interpreted based on the unit # note length, which is potentially dependent on the current meter. # Set tempo_unit to None for now, and the current unit note length will # be filled in later. tempo_unit = None tempo_rate = int(deprecated_tempo_match.group(1)) elif tempo_string_only_match: logging.warning('Ignoring string-only tempo marking: %s', field_content) return else: raise ABCParseError('Could not parse tempo: {}'.format(field_content)) if self._in_header: # If we're in the header, save these until we've finished parsing the # header. The deprecated syntax relies on the unit note length and # meter, which may not be set yet. At the end of the header, we'll fill # in the necessary information and add these. self._header_tempo_unit = tempo_unit self._header_tempo_rate = tempo_rate else: self._add_tempo(tempo_unit, tempo_rate) elif field_name == 'R': pass elif field_name == 'r': pass elif field_name == 'S': pass elif field_name == 's': pass elif field_name == 'T': # Title # http://abcnotation.com/wiki/abc:standard:v2.1#ttune_title if not self._in_header: # TODO(fjord): Non-header titles are used to name parts of tunes, but # NoteSequence doesn't currently have any place to put that information. logging.warning('Ignoring non-header title: %s', field_content) return # If there are multiple titles, separate them with semicolons. if self._ns.sequence_metadata.title: self._ns.sequence_metadata.title += '; ' + field_content else: self._ns.sequence_metadata.title = field_content elif field_name == 'U': pass elif field_name == 'V': raise MultiVoiceError('Multi-voice files are not currently supported.') elif field_name == 'W': pass elif field_name == 'w': pass elif field_name == 'X': # Reference number # http://abcnotation.com/wiki/abc:standard:v2.1#xreference_number self._ns.reference_number = int(field_content) elif field_name == 'Z': pass else: logging.warning( 'Unknown field name %s with content %s', field_name, field_content)Class variables
var ABC_NOTE_TO_MIDIvar BAR_AND_REPEAT_SYMBOLS_PATTERNvar BAR_AND_VARIANT_ENDINGS_PATTERNvar BROKEN_RHYTHM_PATTERNvar CHORD_PATTERNvar DECORATION_PATTERNvar DECORATION_TO_VELOCITYvar FLATS_ORDERvar INFORMATION_FIELD_PATTERNvar INLINE_INFORMATION_FIELD_PATTERNvar KEY_ACCIDENTALS_PATTERNvar KEY_PATTERNvar KEY_TO_PROTO_KEYvar KEY_TO_SIGvar LINE_CONTINUATION_PATTERNvar NOTE_PATTERNvar REPEAT_SYMBOLS_PATTERNvar SHARPS_ORDERvar SIG_TO_KEYSvar SLUR_PATTERNvar TEMPO_DEPRECATED_PATTERNvar TEMPO_PATTERNvar TEMPO_PATTERN_STRING_ONLYvar TEXT_ANNOTATION_PATTERNvar TIE_PATTERNvar TUPLET_PATTERNvar keyvar keysvar sig
Static methods
def parse_key(key)-
Parse an ABC key string.
Expand source code
@staticmethod def parse_key(key): """Parse an ABC key string.""" # http://abcnotation.com/wiki/abc:standard:v2.1#kkey key_match = ABCTune.KEY_PATTERN.match(key) if not key_match: raise ABCParseError('Could not parse key: {}'.format(key)) key_components = list(key_match.groups()) # Shorten the mode to be at most 3 letters long. mode = key_components[2][:3].lower() # "Minor" and "Aeolian" are special cases that are abbreviated to 'm'. # "Major" and "Ionian" are special cases that are abbreviated to ''. if mode in ('min', 'aeo'): mode = 'm' elif mode in ('maj', 'ion'): mode = '' sig = ABCTune.KEY_TO_SIG[''.join(key_components[0:2] + [mode]).lower()] proto_key = ABCTune.KEY_TO_PROTO_KEY[''.join(key_components[0:2]).lower()] if mode == '': # pylint: disable=g-explicit-bool-comparison proto_mode = music_pb2.NoteSequence.KeySignature.MAJOR elif mode == 'm': proto_mode = music_pb2.NoteSequence.KeySignature.MINOR elif mode == 'mix': proto_mode = music_pb2.NoteSequence.KeySignature.MIXOLYDIAN elif mode == 'dor': proto_mode = music_pb2.NoteSequence.KeySignature.DORIAN elif mode == 'phr': proto_mode = music_pb2.NoteSequence.KeySignature.PHRYGIAN elif mode == 'lyd': proto_mode = music_pb2.NoteSequence.KeySignature.LYDIAN elif mode == 'loc': proto_mode = music_pb2.NoteSequence.KeySignature.LOCRIAN else: raise ABCParseError('Unknown mode: {}'.format(mode)) # Match the rest of the string for possible modifications. pos = key_match.end() exppos = key[pos:].find('exp') if exppos != -1: # Only explicit accidentals will be used. accidentals = ABCTune._sig_to_accidentals(0) pos += exppos + 3 else: accidentals = ABCTune._sig_to_accidentals(sig) while pos < len(key): note_match = ABCTune.KEY_ACCIDENTALS_PATTERN.match(key, pos) if note_match: pos += len(note_match.group(0)) note = note_match.group(2).upper() if note_match.group(1): if note_match.group(1) == '^': accidentals[note] = 1 elif note_match.group(1) == '_': accidentals[note] = -1 elif note_match.group(1) == '=': accidentals[note] = 0 else: raise ABCParseError( 'Invalid accidental: {}'.format(note_match.group(1))) else: pos += 1 return accidentals, proto_key, proto_mode
Instance variables
var note_sequence-
Expand source code
@property def note_sequence(self): return self._ns
class ChordError (*args, **kwargs)-
Chords are not supported.
Expand source code
class ChordError(ABCParseError): """Chords are not supported."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class DuplicateReferenceNumberError (*args, **kwargs)-
Found duplicate reference numbers.
Expand source code
class DuplicateReferenceNumberError(ABCParseError): """Found duplicate reference numbers."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class InvalidCharacterError (*args, **kwargs)-
Invalid character.
Expand source code
class InvalidCharacterError(ABCParseError): """Invalid character."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class MultiVoiceError (*args, **kwargs)-
Exception when a multi-voice directive is encountered.
Expand source code
class MultiVoiceError(ABCParseError): """Exception when a multi-voice directive is encountered."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class PartError (*args, **kwargs)-
ABC Parts are not yet supported.
Expand source code
class PartError(ABCParseError): """ABC Parts are not yet supported."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class RepeatParseError (*args, **kwargs)-
Exception when a repeat directive could not be parsed.
Expand source code
class RepeatParseError(ABCParseError): """Exception when a repeat directive could not be parsed."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class TupletError (*args, **kwargs)-
Tuplets are not supported.
Expand source code
class TupletError(ABCParseError): """Tuplets are not supported."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException
class VariantEndingError (*args, **kwargs)-
Variant endings are not yet supported.
Expand source code
class VariantEndingError(ABCParseError): """Variant endings are not yet supported."""Ancestors
- ABCParseError
- builtins.Exception
- builtins.BaseException