benhoyt · September 20, 2025 03:49
diff --git a/count_features.py b/count_features.py
 # $ python3 count_features.py writings/go-python-features.md 
 # go1.25  0 23
 # go1.24  1 29
 # go1.23 15 27
 # go1.22  6 41
 # go1.21  8 50
 # go1.20  4 33
 # go1.19  0 14
 # go1.18 15 31
 # go1.17  3 15
 # go1.16  0 36
 # go1.15  0 21
 # go1.14  1 18
 # go1.13  2 35
 # go1.12  0 14
 # go1.11  0  9
 # go1.10  0 22
 # go1.9   6 28
 # go1.8   1 22
 # go1.7   0 40
 # go1.6   0 16
 # go1.5   1 44
 # go1.4   1 20
 # go1.3   0 13
 # go1.2   1 36
 # go1.1   2 48

 import os
 from fileinput import input, lineno

 def smh(s):
 	match s:
 		case 'S':
 			return 1
 		case 'M':
 			return 5
 		case 'L':
 			return 15
 	assert False, f'expected "SMH", not {s!r} on line {lineno()}'


 f = input(encoding='utf-8')

 go_version = ''
 while go_version != '1.1':
 	for line in f:
 		if line.startswith('Go '):
 			go_version = line[3:].strip()
 			break

 	try:
 		line = next(f)
 	except StopIteration:
 		assert False, f'expected line after {lineno()}'
 	assert line.startswith('---'), f'expected "---" on line {lineno()}'

 	try:
 		line = next(f)
 	except StopIteration:
 		assert False, f'expected line after {lineno()}'
 	assert line.startswith('language:'), f'expected "language:" on line {lineno()}'
 	s = line[len('language:'):].strip()
 	language_n = int(s) if s else 0

 	language_sum = 0
 	for line in f:
 		if not line.startswith('- '):
 			break
 		assert line[2] in 'SML' and line[3] == ' ', f'expected "SMH " on line {lineno()}'
 		language_sum += smh(line[2])
 	if language_sum != language_n:
 		assert False, f'{go_version} expected language sum {language_sum} not {language_n} on line {lineno()}'

 	assert line.startswith('stdlib:'), f'expected "stdlib:" on line {lineno()}'
 	s = line[len('stdlib:'):].strip()
 	stdlib_n = int(s) if s else 0

 	# TODO test unique package name
 	stdlib_sum = 0
 	packages = set()
 	for line in f:
 		if not line.startswith('- '):
 			break
 		assert line[2] in 'SML' and line[3] == ' ', f'expected "SMH " on line {lineno()}'
 		stdlib_sum += smh(line[2])
 		package = line[4:].split(':', maxsplit=1)[0]
 		if package in packages:
 			assert False, f'{go_version} package {package} not unique on line {lineno()}'
 		packages.add(package)
 	if stdlib_sum != stdlib_n:
 		assert False, f'{go_version} expected stdlib sum {stdlib_sum} not {stdlib_n} on line {lineno()}'

 	print(f'go{go_version:4} {language_sum:2} {stdlib_sum:2}')
diff --git a/go-python-features.md b/go-python-features.md
diff --git a/python-features.txt b/python-features.txt
 Python 3.3 - 2012-09-29
 -----------------------
 language:
 - S yield from
 - S u'unicode' syntax
 - S reworked I/O exception hierarchy
 - S __qualname__
 - S Unicode name aliases
 - S range equality
 - S count/find/index integer
 - S bytearray fill
 - S list/bytearray: copy, clear
 - S str: casefold
 stdlib:
 - M faulthandler
 - M ipaddress
 - M lzma
 - M unittest.mock
 - M venv
 - S inspect: signature
 - S sys: implementation
 - S types: SimpleNamespace
 - S importlib: updates
 - S open: opener
 - S print: flush



 Python 3.2 - 2011-02-20
 -----------------------
 language:
 - S stable C API
 - S __pycache__ directory
 - S version-tagged .so files
 - S hasattr only catches AttributeError
 - S str(float) == repr(float)
 - S format: #, str.format_map
 - S del outer
 - S ResourceWarning
 - S range: index, count
 - S callable
 stdlib:
 - M argparse
 - M concurrent.futures
 - M html
 - M sysconfig
 - S logging: dict-based config, other improvements
 - S wsgiref: handlers.read_environ
 - S memoryview.release
 - S struct sequence types subclasses of tuple
 - S email: str and bytes fixes
 - S xml: etree.ElementTree updates
 - S functools: lru_cache, wraps changes, total_ordering, cmp_to_key
 - S itertools: accumulate
 - S collections: Counter improvements, OrderedDict.move_to_end, deque.count, deque.reverse
 - S threading: Barrier
 - S datetime: timezone, timedelta * and /
 - S math: new C99 functions
 - S abc: abstractclassmethod, abstractstaticmethod
 - S io: BytesIO.getbuffer
 - S reprlib: recursive_repr
 - S csv: unix_dialect
 - S contextlib: ContextDecorator
 - S various: context managers (FTP, fileinput, TarFile, etc)
 - S gzip: implements io.BufferedIOBase
 - S ast: literal_eval improvements
 - S os: fsencode, fsdecode
 - S shutil: copytree ignore_dangling_symlinks and copy_function
 - S socket: detach
 - S ssl: various improvements
 - S http: client improvements
 - S unittest: various improvements
 - S asyncore: handle_accepted
 - S tempfile: TemporaryDirectory
 - S inspect: getgeneratorstate, getattr_static
 - S dis: code_info, show_code
 - S site: getsitepackages, getuserbase, getusersitepackages
 - S configparser: improvements
 - S urllib: parse improvements
 - S mailbox: str and bytes fixes


 Python 3.1 - 2009-06-27
 -----------------------
 language:
 - S executable directories and .zip files with __main__.py
 - S multiple context managers in single "with" statement
 - S str: format thousands separator, format automatic field numbering
 - S int: bit_length
 stdlib:
 - M collections: OrderedDict, Counter, namedtuple rename
 - S bytes: maketrans
 - S bytearray: maketrans
 - M tkinter.ttk
 - S gzip: context manager support
 - S bz2: context manager support
 - S decimal: Decimal.from_float
 - S itertools: combinations_with_replacement, compress, count step
 - S re: sub/subn/split flags param
 - S logging: NullHandler
 - S unittest: skipUnless, expectedFailure, assertRaises
 - M importlib
	# $ python3 count_features.py writings/go-python-features.md
	# go1.25 0 23
	# go1.24 1 29
	# go1.23 15 27
	# go1.22 6 41
	# go1.21 8 50
	# go1.20 4 33
	# go1.19 0 14
	# go1.18 15 31
	# go1.17 3 15
	# go1.16 0 36
	# go1.15 0 21
	# go1.14 1 18
	# go1.13 2 35
	# go1.12 0 14
	# go1.11 0 9
	# go1.10 0 22
	# go1.9 6 28
	# go1.8 1 22
	# go1.7 0 40
	# go1.6 0 16
	# go1.5 1 44
	# go1.4 1 20
	# go1.3 0 13
	# go1.2 1 36
	# go1.1 2 48

	import os
	from fileinput import input, lineno

	def smh(s):
	match s:
	case 'S':
	return 1
	case 'M':
	return 5
	case 'L':
	return 15
	assert False, f'expected "SMH", not {s!r} on line {lineno()}'


	f = input(encoding='utf-8')

	go_version = ''
	while go_version != '1.1':
	for line in f:
	if line.startswith('Go '):
	go_version = line[3:].strip()
	break

	try:
	line = next(f)
	except StopIteration:
	assert False, f'expected line after {lineno()}'
	assert line.startswith('---'), f'expected "---" on line {lineno()}'

	try:
	line = next(f)
	except StopIteration:
	assert False, f'expected line after {lineno()}'
	assert line.startswith('language:'), f'expected "language:" on line {lineno()}'
	s = line[len('language:'):].strip()
	language_n = int(s) if s else 0

	language_sum = 0
	for line in f:
	if not line.startswith('- '):
	break
	assert line[2] in 'SML' and line[3] == ' ', f'expected "SMH " on line {lineno()}'
	language_sum += smh(line[2])
	if language_sum != language_n:
	assert False, f'{go_version} expected language sum {language_sum} not {language_n} on line {lineno()}'

	assert line.startswith('stdlib:'), f'expected "stdlib:" on line {lineno()}'
	s = line[len('stdlib:'):].strip()
	stdlib_n = int(s) if s else 0

	# TODO test unique package name
	stdlib_sum = 0
	packages = set()
	for line in f:
	if not line.startswith('- '):
	break
	assert line[2] in 'SML' and line[3] == ' ', f'expected "SMH " on line {lineno()}'
	stdlib_sum += smh(line[2])
	package = line[4:].split(':', maxsplit=1)[0]
	if package in packages:
	assert False, f'{go_version} package {package} not unique on line {lineno()}'
	packages.add(package)
	if stdlib_sum != stdlib_n:
	assert False, f'{go_version} expected stdlib sum {stdlib_sum} not {stdlib_n} on line {lineno()}'

	print(f'go{go_version:4} {language_sum:2} {stdlib_sum:2}')
	Python 3.3 - 2012-09-29
	-----------------------
	language:
	- S yield from
	- S u'unicode' syntax
	- S reworked I/O exception hierarchy
	- S __qualname__
	- S Unicode name aliases
	- S range equality
	- S count/find/index integer
	- S bytearray fill
	- S list/bytearray: copy, clear
	- S str: casefold
	stdlib:
	- M faulthandler
	- M ipaddress
	- M lzma
	- M unittest.mock
	- M venv
	- S inspect: signature
	- S sys: implementation
	- S types: SimpleNamespace
	- S importlib: updates
	- S open: opener
	- S print: flush



	Python 3.2 - 2011-02-20
	-----------------------
	language:
	- S stable C API
	- S __pycache__ directory
	- S version-tagged .so files
	- S hasattr only catches AttributeError
	- S str(float) == repr(float)
	- S format: #, str.format_map
	- S del outer
	- S ResourceWarning
	- S range: index, count
	- S callable
	stdlib:
	- M argparse
	- M concurrent.futures
	- M html
	- M sysconfig
	- S logging: dict-based config, other improvements
	- S wsgiref: handlers.read_environ
	- S memoryview.release
	- S struct sequence types subclasses of tuple
	- S email: str and bytes fixes
	- S xml: etree.ElementTree updates
	- S functools: lru_cache, wraps changes, total_ordering, cmp_to_key
	- S itertools: accumulate
	- S collections: Counter improvements, OrderedDict.move_to_end, deque.count, deque.reverse
	- S threading: Barrier
	- S datetime: timezone, timedelta * and /
	- S math: new C99 functions
	- S abc: abstractclassmethod, abstractstaticmethod
	- S io: BytesIO.getbuffer
	- S reprlib: recursive_repr
	- S csv: unix_dialect
	- S contextlib: ContextDecorator
	- S various: context managers (FTP, fileinput, TarFile, etc)
	- S gzip: implements io.BufferedIOBase
	- S ast: literal_eval improvements
	- S os: fsencode, fsdecode
	- S shutil: copytree ignore_dangling_symlinks and copy_function
	- S socket: detach
	- S ssl: various improvements
	- S http: client improvements
	- S unittest: various improvements
	- S asyncore: handle_accepted
	- S tempfile: TemporaryDirectory
	- S inspect: getgeneratorstate, getattr_static
	- S dis: code_info, show_code
	- S site: getsitepackages, getuserbase, getusersitepackages
	- S configparser: improvements
	- S urllib: parse improvements
	- S mailbox: str and bytes fixes


	Python 3.1 - 2009-06-27
	-----------------------
	language:
	- S executable directories and .zip files with __main__.py
	- S multiple context managers in single "with" statement
	- S str: format thousands separator, format automatic field numbering
	- S int: bit_length
	stdlib:
	- M collections: OrderedDict, Counter, namedtuple rename
	- S bytes: maketrans
	- S bytearray: maketrans
	- M tkinter.ttk
	- S gzip: context manager support
	- S bz2: context manager support
	- S decimal: Decimal.from_float
	- S itertools: combinations_with_replacement, compress, count step
	- S re: sub/subn/split flags param
	- S logging: NullHandler
	- S unittest: skipUnless, expectedFailure, assertRaises
	- M importlib