[Jython-dev] exec <file> in <dictionary>

[brian z. <bz...@zi...>]

I was trying to use the following syntax in Jython but I get an exception:

>>> t = {}
>>> exec open(filename) in t

Traceback (innermost last):
  File "install.py", line 381, in ?
  File "install.py", line 47, in run
  File "install.py", line 71, in detectComponents
  File "install.py", line 89, in readProperties
TypeError: exec: argument 1 must be string or code object

This works in CPython and appears to be part of the spec:

"The first expression should evaluate to either a string, an open file
object, or a code object. ...  If it is an open file, the file is parsed
until EOF and executed."

http://python.org/doc/current/ref/exec.html

Additionally, in CPython 2.0, if the file is closed it is re-opened and
executed.

I also tested whether StringIO could be substited for a file and it appears
to fail:

>>> from StringIO import StringIO
>>> s = StringIO("a = 'x'")
>>> s
<StringIO.StringIO instance at 007E1C1C>
>>> t = {}
>>> exec s in t
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: exec 1st arg must be string, code or file object
>>>

Given this, I've enclosed a working diff which mimics the exact behaviour of
CPython 2.0.

thanks,

brian