Annoying problem with rexec

[david.stegbauer at cz.opel.com]

Hi Ralf,

You create LOCAL name "open" and using it to open files.

Function *definition* is "executed" before run and I *guess* the local name
"open" is somehow interned. (See built-in function "intern" in library
reference.) Then during looking up for function "open" is first found interned
"open", not the built-in one. It is the same case as if you assign to "stdout"
instead of to "sys.stdout".

So you have to use either "global open" or "__builtins__.open=saved_open". The
last one is better, I thing.

David

8<----------Ralf Doering wrote:-------------
>
>def testrexec():
>        temp = "/tmp/test.1"
>        print "**** About to open:", temp
>        f2 = open(temp,"w")
>        f2.write("I WAS HERE.\n")
>        f2.close()
>        print "****",temp, "closed ."
>        saved_open = open
>        open = saved_open
>
>As a result, I get:
>
>>>> testrexec.testrexec_ok()
>**** About to open: /tmp/test.1
>Traceback (innermost last):
>  File "<stdin>", line 1, in ?
>  File "testrexec.py", line 8, in testrexec
>    f2 = open(temp,"w")
>NameError: open
>>>>
>
>
>However, if I insert a "global open" right after the start of the
>function, it works as expected.