[Python-bugs-list] [ python-Bugs-764548 ] SRE doesn't use isinstance

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Bugs item #764548, was opened at 2003-07-02 14:20
Message generated for change (Comment added) made by effbot
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Category: Regular Expressions
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Ronald Oussoren (ronaldoussoren)
>Assigned to: Just van Rossum (jvr)
Summary: SRE doesn't use isinstance

Initial Comment:

The following code fails with a TypeError:

#--------------------------------
import re

class MyUnicode(unicode):
   pass

val = MyUnicode("foobar")

r = re.compile(val)
#--------------------------------

This is caused by a check in sre.py: it checks if the
type of the pattern is str or unicode, instead of
testing if the value is an instance of those types.

This is not a completely theoretical problem: PyObjC
uses a subclass of unicode to represent Objective-C
strings.






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>Comment By: Fredrik Lundh (effbot)
Date: 2003-07-02 21:47

Message:
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"Shall I just go ahead and check it in?"

It would be most excellent if you did.

Cheers /F

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Comment By: Just van Rossum (jvr)
Date: 2003-07-02 20:58

Message:
Logged In: YES 
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D'oh, 1.5.2 is so long ago I could've sworn it didn't have 
isinstance(). However, 1.5.2 doesn't accept tuples for the second 
argument. I've attached a new patch, but it's so easy to still make 
it work with 1.5.2 that I didn't bother to break that compatibility ;-
) Shall I just go ahead and check it in?

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Comment By: Fredrik Lundh (effbot)
Date: 2003-07-02 20:43

Message:
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Just, note that "isinstance" is supported in 1.5.2 (but
unicode strings aren't).

And I think it's safe to skip 1.5.2 support in SRE;
I suggest changing the "baseline" to 2.1.

If you agree, feel free to assign this item to your-
self, and fix the code.

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Comment By: Just van Rossum (jvr)
Date: 2003-07-02 16:54

Message:
Logged In: YES 
user_id=92689

Here's a patch that should fix the problem, while remaining 
compatible with 1.5.2. Fredrik, please assign to me if you think 
the patch is ok. Preferably before 2.3 final is out ;-)

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