Patches item #1548388, was opened at 2006-08-29 03:33
Message generated for change (Comment added) made by rhettinger
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Category: Core (C code)
Group: Python 3000
Status: Open
Resolution: None
Priority: 5
Submitted By: Georg Brandl (gbrandl)
Assigned to: Guido van Rossum (gvanrossum)
Summary: set comprehensions
Initial Comment:
This is a big one:
* cleanup grammar; unifies listcomp/genexp grammar
which means that [x for x in 1, 2] is no longer valid
* cleanup comprehension compiling code (unifies all AST
code for the three comprehensions and most of the
compile.c code)
* add set comprehensions
This patch modifies list comprehensions to be
implemented more like generator expressions: in a
separate function, which means that the loop variables
will not leak any more.
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>Comment By: Raymond Hettinger (rhettinger)
Date: 2006-08-31 18:15
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Would it be an oversimplfication for list and set comps to
keep everything in one code block and just hide the list
loop variables by renaming them: x --> __[x]
That approach would only require a minimal patch, and it
would make for a cleaner disassembly.
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Comment By: Georg Brandl (gbrandl)
Date: 2006-08-31 14:55
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Attaching slightly revised patch and bytecode comparison.
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Comment By: Raymond Hettinger (rhettinger)
Date: 2006-08-29 17:30
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Can you post a before and disassembly of some list and set
comprehensions.
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Comment By: Georg Brandl (gbrandl)
Date: 2006-08-29 14:09
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test_compiler and test_transformer fail because the compiler
package hasn't been updated yet.
test_dis fails because list comprehensions now generate
different bytecode.
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Comment By: Guido van Rossum (gvanrossum)
Date: 2006-08-29 12:59
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Nice!
I see failures in 4 tests:
test_compiler test_dis test_transformer test_univnewlines
test_univnewlines is trivial (it's deleting a variable
leaked out of a list comprehension); haven't looked at the
rest in detail
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Comment By: Georg Brandl (gbrandl)
Date: 2006-08-29 03:34
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The previously attached patch contains only the important
files. The FULL patch (attached now) also contains syntax
fixes in python files so that the test suite is mostly passing.
Note that the compiler package isn't ready yet.
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