You can also catch a SyntaxError like any other exception.
Yes, people are able to write backwards compatible scripts... by avoiding some features, or by using more than a single file.
What I'm describing was just a desire for a very simple "this script requires python version >= X" error, with the ability to write unfettered python version X code below it, in a single file script.
import sys
if sys.version_info.major < 3:
raise Exception("this script requires python version >= 3")
print(f"whee")
And run it with python2, or a python3 < 3.6.
> cat test.py
import sys
if sys.version_info.major < 3:
raise Exception("this script requires python version >= 3")
print(f"test")
> python2 test.py
File "test.py", line 5
print(f"test")
^
SyntaxError: invalid syntax
from __future__ import absolute_import, division, print_function, unicode_literals
import sys
if sys.version_info[0] < 3:
print("Needs Python 3+")
sys.exit(1)
else:
prog = r'''
def help():
print("Help: ...")
def do_spam(*args):
print("spamming")
def main(args):
match args:
case [subcommand, *args]:
return globals()[f'do_{subcommand}'](*args)
case _:
return help()
if __name__ == '__main__':
try:
status = main(sys.argv[1:])
sys.exit(int(status if status is not None else 0))
except Exception as e:
import traceback
traceback.print_exc(e)
sys.exit(1)
'''
compile(prog, '', 'exec')
exec(prog)