strange syntax error

_wolf wolfgang.lipp at gmail.com
Fri Jun 4 13:31:00 EDT 2010


this may not be an earth-shattering deficiency of python, but i still
wonder about the rationale behind the following behavior: when i
run ::

  source = """
  print( 'helo' )
  if __name__ == '__main__':
    print( 'yeah!' )

  #"""

  print( compile( source, '<whatever>', 'exec' ) )

i get ::

    File "<whatever>", line 6
      #
      ^
  SyntaxError: invalid syntax

i can avoid this exception by (1) deleting the trailing ``#``; (2)
deleting or outcommenting the ``if __name__ == '__main__':\n
print( 'yeah!' )`` lines; (3) add a newline to very end of the
source.

moreover, if i have the source end without a trailing newline right
behind the ``print( 'yeah!' )``, the source will also compile without
error.

i could also reproduce this behavior with python 2.6, so it’s not new
to the 3k series.

i find this error to be highly irritating, all the more since when i
put above source inside a file and execute it directly or have it
imported, no error will occur—which is the expected behavior.

a ``#`` (hash) outside a string literal should always represent the
start of a (possibly empty) comment in a python source; moreover, the
presence or absence of a  ``if __name__ == '__main__'`` clause should
not change the interpretation of a soure on a syntactical level.

can anyone reproduce the above problem, and/or comment on the
phenomenon?

cheers



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