[Patches] [ python-Patches-572936 ] (?(id/name)yes|no) re implementation

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Patches item #572936, was opened at 2002-06-24 03:41
Message generated for change (Comment added) made by loewis
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Category: Library (Lib)
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Gustavo Niemeyer (niemeyer)
Assigned to: Fredrik Lundh (effbot)
Summary: (?(id/name)yes|no) re implementation

Initial Comment:
This patch implements a regular expression feature, which allows   
some interesting patterns, in the same way as implemented in perl.   
For example, (?(1)yes|no) matches with "yes" if group "1" exists, and   
with "no", if it doesn't. Without this feature, the regular expression   
must be duplicated to get the same results. In addition to perl's 
feature, it will also accept a Python named group as argument. 
   
Here's an example:   
   
(<)?\w+@\w+(\.\w+)+(?(1)>)   
  
This is a poor email matching regular expression, which will match   
with or without the "<>" symbols.   
   

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>Comment By: Martin v. Löwis (loewis)
Date: 2003-04-19 10:50

Message:
Logged In: YES 
user_id=21627

If you add new opcodes, you should also change SRE_MAGIC.

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