Fix Python 3 support

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [2.7]
+        python-version: [3]
 
     steps:
     - uses: actions/checkout@v1

transposer.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # encoding: utf-8
 """
 transposer.py
@@ -13,158 +13,185 @@
 import os
 import re, getopt
 
-key_list = [('A',), ('A#', 'Bb'), ('B',), ('C',), ('C#', 'Db'), ('D',),
-            ('D#', 'Eb'), ('E',), ('F',), ('F#', 'Gb'), ('G',), ('G#', 'Ab')]
-
-sharp_flat = ['#', 'b']
+key_list = [
+    ("A",),
+    ("A#", "Bb"),
+    ("B",),
+    ("C",),
+    ("C#", "Db"),
+    ("D",),
+    ("D#", "Eb"),
+    ("E",),
+    ("F",),
+    ("F#", "Gb"),
+    ("G",),
+    ("G#", "Ab"),
+]
+
+sharp_flat = ["#", "b"]
 sharp_flat_preferences = {
-	'A' : '#',
-	'A#': 'b',
-	'Bb': 'b',
-	'B' : '#',
-	'C' : 'b',
-	'C#': 'b',
-	'Db': 'b',
-	'D' : '#',
-	'D#': 'b',
-	'Eb': 'b',
-	'E' : '#',
-	'F' : 'b',
-	'F#': '#',
-	'Gb': '#',
-	'G' : '#',
-	'G#': 'b',
-	'Ab': 'b',
-	}
+    "A": "#",
+    "A#": "b",
+    "Bb": "b",
+    "B": "#",
+    "C": "b",
+    "C#": "b",
+    "Db": "b",
+    "D": "#",
+    "D#": "b",
+    "Eb": "b",
+    "E": "#",
+    "F": "b",
+    "F#": "#",
+    "Gb": "#",
+    "G": "#",
+    "G#": "b",
+    "Ab": "b",
+}
 
 key_regex = re.compile(r"[ABCDEFG][#b]?")
 
+
 def get_index_from_key(source_key):
-	"""Gets the internal index of a key
-	>>> get_index_from_key('Bb')
-	1
-	"""
-	for key_names in key_list:
-		if source_key in key_names:
-			return key_list.index(key_names)
-	raise Exception("Invalid key: %s" % source_key)
+    """Gets the internal index of a key
+    >>> get_index_from_key('Bb')
+    1
+    """
+    for key_names in key_list:
+        if source_key in key_names:
+            return key_list.index(key_names)
+    raise Exception("Invalid key: %s" % source_key)
+
 
 def get_key_from_index(index, to_key):
-	"""Gets the key at the given internal index.
-	Sharp or flat depends on the target key.
-	>>> get_key_from_index(1, 'Eb')
-	'Bb'
-	"""
-	key_names = key_list[index % len(key_list)]
-	if len(key_names) > 1:
-		sharp_or_flat = sharp_flat.index(sharp_flat_preferences[to_key])
-		return key_names[sharp_or_flat]
-	return key_names[0]
+    """Gets the key at the given internal index.
+    Sharp or flat depends on the target key.
+    >>> get_key_from_index(1, 'Eb')
+    'Bb'
+    """
+    key_names = key_list[index % len(key_list)]
+    if len(key_names) > 1:
+        sharp_or_flat = sharp_flat.index(sharp_flat_preferences[to_key])
+        return key_names[sharp_or_flat]
+    return key_names[0]
+
 
 def get_transponation_steps(source_key, target_key):
-	"""Gets the number of half tones to transpose
-	>>> get_transponation_steps('D', 'C')
-	-2
-	"""
-	source_index = get_index_from_key(source_key)
-	target_index = get_index_from_key(target_key)
-	return target_index - source_index
+    """Gets the number of half tones to transpose
+    >>> get_transponation_steps('D', 'C')
+    -2
+    """
+    source_index = get_index_from_key(source_key)
+    target_index = get_index_from_key(target_key)
+    return target_index - source_index
+
 
 def transpose_file(file_name, from_key, to_key):
-	"""Transposes a file from a key to another.
-	>>> transpose_file('example.txt', 'D', 'E')
-	'Rocking start, jazzy ending\\n| E | A B | Cm7#11/D# |\\n'
-	"""
-	direction = get_transponation_steps(from_key, to_key)
-	result = ''
-	try:
-		for line in open(file_name):
-			result += transpose_line(line, direction, to_key)
-		return result
-	except IOError:
-		print("Invalid filename!")
-		usage()
+    """Transposes a file from a key to another.
+    >>> transpose_file('example.txt', 'D', 'E')
+    'Rocking start, jazzy ending\\n| E | A B | Cm7#11/D# |\\n'
+    """
+    direction = get_transponation_steps(from_key, to_key)
+    result = ""
+    try:
+        for line in open(file_name):
+            result += transpose_line(line, direction, to_key)
+        return result
+    except IOError:
+        print("Invalid filename!")
+        usage()
+
 
 def transpose_line(source_line, direction, to_key):
-	"""Transposes a line a number of keys if it starts with a pipe. Examples:
-	>>> transpose_line('| A | A# | Bb | C#m7/F# |', -2, 'C')
-	'| G | Ab | Ab | Bm7/E |'
-
-	Different keys will be sharp or flat depending on target key.
-	>>> transpose_line('| A | A# | Bb | C#m7/F# |', -2, 'D')
-	'| G | G# | G# | Bm7/E |'
-
-	It will use the more common key if sharp/flat, for example F# instead of Gb.
-	>>> transpose_line('| Gb |', 0, 'Gb')
-	'| F# |'
-
-	Lines not starting with pipe will not be transposed
-	>>> transpose_line('A | Bb |', -2, 'C')
-	'A | Bb |'
-	"""
-	if source_line[0] != '|':
-		return source_line
-	source_chords = key_regex.findall(source_line)
-	return recursive_line_transpose(source_line, source_chords, direction, to_key)
-
+    """Transposes a line a number of keys if it starts with a pipe. Examples:
+    >>> transpose_line('| A | A# | Bb | C#m7/F# |', -2, 'C')
+    '| G | Ab | Ab | Bm7/E |'
+
+    Different keys will be sharp or flat depending on target key.
+    >>> transpose_line('| A | A# | Bb | C#m7/F# |', -2, 'D')
+    '| G | G# | G# | Bm7/E |'
+
+    It will use the more common key if sharp/flat, for example F# instead of Gb.
+    >>> transpose_line('| Gb |', 0, 'Gb')
+    '| F# |'
+
+    Lines not starting with pipe will not be transposed
+    >>> transpose_line('A | Bb |', -2, 'C')
+    'A | Bb |'
+    """
+    if source_line[0] != "|":
+        return source_line
+    source_chords = key_regex.findall(source_line)
+    return recursive_line_transpose(source_line, source_chords, direction, to_key)
+
+
 def recursive_line_transpose(source_line, source_chords, direction, to_key):
-	if not source_chords or not source_line:
-		return source_line
-	source_chord = source_chords.pop(0)
-	chord_index = source_line.find(source_chord)
-	after_chord_index = chord_index + len(source_chord)
-
-	return source_line[:chord_index] + \
-		   transpose(source_chord, direction, to_key) + \
-		   recursive_line_transpose(source_line[after_chord_index:], source_chords, direction, to_key)
+    if not source_chords or not source_line:
+        return source_line
+    source_chord = source_chords.pop(0)
+    chord_index = source_line.find(source_chord)
+    after_chord_index = chord_index + len(source_chord)
+
+    return (
+        source_line[:chord_index]
+        + transpose(source_chord, direction, to_key)
+        + recursive_line_transpose(
+            source_line[after_chord_index:], source_chords, direction, to_key
+        )
+    )
 
 
 def transpose(source_chord, direction, to_key):
-	"""Transposes a chord a number of half tones.
-	Sharp or flat depends on target key.
-	>>> transpose('C', 3, 'Bb')
-	'Eb'
-	"""
-	source_index = get_index_from_key(source_chord)
-	return get_key_from_index(source_index + direction, to_key)
+    """Transposes a chord a number of half tones.
+    Sharp or flat depends on target key.
+    >>> transpose('C', 3, 'Bb')
+    'Eb'
+    """
+    source_index = get_index_from_key(source_chord)
+    return get_key_from_index(source_index + direction, to_key)
 
 
 def usage():
-	print 'Usage:'
-	print '%s --from=Eb --to=F# input_filename' % os.path.basename(__file__)
-	sys.exit(2)
+    print("Usage:")
+    print("%s --from=Eb --to=F# input_filename" % os.path.basename(__file__))
+    sys.exit(2)
+
 
 def main():
-	from_key = 'C'
-	to_key = 'C'
-	file_name = None
-	try:
-		options, arguments = getopt.getopt(sys.argv[1:], 'f:t:', ['from=', 'to=', 'doctest'])
-	except getopt.GetoptError, err:
-		print str(err)
-		usage()
-		sys.exit(2)
-	for option, value in options:
-		if option in ('-f', '--from'):
-			from_key = value
-		elif option in ('-t', '--to'):
-			to_key = value
-		elif option == '--doctest':
-			import doctest
-			doctest.testmod()
-			exit()
-		else:
-			usage()
-
-	if arguments:
-		file_name = arguments[0]
-	else:
-		usage()
-
-	result = transpose_file(file_name, from_key, to_key)
-
-	print("Result (%s -> %s):" % (from_key, to_key))
-	print(result)
-
-if __name__ == '__main__':
-	main()
+    from_key = "C"
+    to_key = "C"
+    file_name = None
+    try:
+        options, arguments = getopt.getopt(
+            sys.argv[1:], "f:t:", ["from=", "to=", "doctest"]
+        )
+    except getopt.GetoptError as err:
+        print(str(err))
+        usage()
+        sys.exit(2)
+    for option, value in options:
+        if option in ("-f", "--from"):
+            from_key = value
+        elif option in ("-t", "--to"):
+            to_key = value
+        elif option == "--doctest":
+            import doctest
+
+            doctest.testmod()
+            exit()
+        else:
+            usage()
+
+    if arguments:
+        file_name = arguments[0]
+    else:
+        usage()
+
+    result = transpose_file(file_name, from_key, to_key)
+
+    print("Result (%s -> %s):" % (from_key, to_key))
+    print(result)
+
+
+if __name__ == "__main__":
+    main()