Re: [Python-Dev] problem with genexp
On 2/20/06, Jiwon Seo [EMAIL PROTECTED] wrote:
Regarding this Grammar change; (last October)
from argument: [test '=' ] test [gen_for]
to argument: test [gen_for] | test '=' test ['(' gen_for ')']
- to raise error for bar(a = i for i in range(10)) )
I think we should change it to
argument: test [gen_for] | test '=' test
instead of
argument: test [gen_for] | test '=' test ['(' gen_for ')']
that is, without ['(' gen_for ')'] . We don't need that extra term,
because test itself includes generator expressions - with all those
parensises.
Works for me, committed.
n
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Re: [Python-Dev] problem with genexp
Regarding this Grammar change; (last October)
from argument: [test '=' ] test [gen_for]
to argument: test [gen_for] | test '=' test ['(' gen_for ')']
- to raise error for bar(a = i for i in range(10)) )
I think we should change it to
argument: test [gen_for] | test '=' test
instead of
argument: test [gen_for] | test '=' test ['(' gen_for ')']
that is, without ['(' gen_for ')'] . We don't need that extra term,
because test itself includes generator expressions - with all those
parensises.
Actually with that extra ['(' gen_for ')'] , foo(a= 10 (for y in
'a')) is grammartically correct ; although that error seems to be
checked elsewhere.
I tested without ['(' gen_for ')'] , and worked fine passing
Lib/test/test_genexps.py
-Jiwon
On 10/20/05, Neal Norwitz [EMAIL PROTECTED] wrote:
On 10/16/05, Neal Norwitz [EMAIL PROTECTED] wrote:
On 10/10/05, Neal Norwitz [EMAIL PROTECTED] wrote:
There's a problem with genexp's that I think really needs to get
fixed. See http://python.org/sf/1167751 the details are below. This
code:
foo(a = i for i in range(10))
I agree with the bug report that the code should either raise a
SyntaxError or do the right thing.
The change to Grammar/Grammar below seems to fix the problem and all
the tests pass. Can anyone comment on whether this fix is
correct/appropriate? Is there a better way to fix the problem?
Since no one responded other than Jiwon, I checked in this change. I
did *not* backport it since what was syntactically correct in 2.4.2
would raise an error in 2.4.3. I'm not sure which is worse. I'll
leave it up to Anthony whether this should be backported.
BTW, the change was the same regardless of old code vs. new AST code.
n
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Re: [Python-Dev] problem with genexp
On 10/16/05, Neal Norwitz [EMAIL PROTECTED] wrote:
On 10/10/05, Neal Norwitz [EMAIL PROTECTED] wrote:
There's a problem with genexp's that I think really needs to get
fixed. See http://python.org/sf/1167751 the details are below. This
code:
foo(a = i for i in range(10))
I agree with the bug report that the code should either raise a
SyntaxError or do the right thing.
The change to Grammar/Grammar below seems to fix the problem and all
the tests pass. Can anyone comment on whether this fix is
correct/appropriate? Is there a better way to fix the problem?
-argument: [test '='] test [gen_for] # Really [keyword '='] test
+argument: test [gen_for] | test '=' test ['(' gen_for ')'] # Really
[keyword '='] test
The other option would be changes in the Python/compile.c (somewhat)
like following
diff -r2.352 compile.c
6356c6356,6362
- if (TYPE(n) == argument NCH(n) == 3) {
---
+ if (TYPE(n) == argument NCH(n) == 4) {
+ PyErr_SetString(PyExc_SyntaxError,
+ invalid syntax);
+ symtable_error(st, n-n_lineno);
+ return;
+ }
+ else if (TYPE(n) == argument NCH(n) == 3) {
but IMO, changing the Grammar looks more obvious.
n
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Re: [Python-Dev] problem with genexp
On 10/10/05, Neal Norwitz [EMAIL PROTECTED] wrote:
There's a problem with genexp's that I think really needs to get
fixed. See http://python.org/sf/1167751 the details are below. This
code:
foo(a = i for i in range(10))
I agree with the bug report that the code should either raise a
SyntaxError or do the right thing.
The change to Grammar/Grammar below seems to fix the problem and all
the tests pass. Can anyone comment on whether this fix is
correct/appropriate? Is there a better way to fix the problem?
-argument: [test '='] test [gen_for] # Really [keyword '='] test
+argument: test [gen_for] | test '=' test ['(' gen_for ')'] # Really
[keyword '='] test
n
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Re: [Python-Dev] problem with genexp
Neal Norwitz wrote: There's a problem with genexp's that I think really needs to get fixed. See http://python.org/sf/1167751 the details are below. This code: I agree with the bug report that the code should either raise a SyntaxError or do the right thing. I agree it should be a SyntaxError - I believe the AST compiler actually raises one in this situation. Cheers, Nick. -- Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia --- http://boredomandlaziness.blogspot.com ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] problem with genexp
On 10/11/05, Nick Coghlan [EMAIL PROTECTED] wrote: Neal Norwitz wrote: There's a problem with genexp's that I think really needs to get fixed. See http://python.org/sf/1167751 the details are below. This code: I agree with the bug report that the code should either raise a SyntaxError or do the right thing. I agree it should be a SyntaxError - I believe the AST compiler actually raises one in this situation. Could someone add a test for this on the AST branch? BTW, it looks like doctest is the way to go for SyntaxError tests. There are older tests, like test_scope.py, that use separate files with bad syntax (and lots of extra kludges in the infrastructure to ignore the fact that those .py files can't be compiled). Jeremy ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] problem with genexp
Nick Coghlan wrote:
Neal Norwitz wrote:
There's a problem with genexp's that I think really needs to get
fixed. See http://python.org/sf/1167751 the details are below. This
code:
I agree with the bug report that the code should either raise a
SyntaxError or do the right thing.
I agree it should be a SyntaxError - I believe the AST compiler actually
raises one in this situation.
I was half right. Both the normal compiler and the AST compiler give a
SyntaxError if you write:
foo((a=i for i in range(10)))
The problem is definitely on the parser end though:
Py compiler.parse(foo(x=i for i in range(10)))
Module(None, Stmt([Discard(CallFunc(Name('foo'), [Keyword('x', Name('i'))],
None, None))]))
It's getting to what looks like a valid keyword argument in x=i and throwing
the rest of it away, when it should be flagging a syntax error (the parser's
limited lookahead should still be enough to spot the erroneous 'for' keyword
and bail out). The error will be even more obscure if there is an i visible
from the location of the function call.
Whereas when it's parenthesised correctly, the parse tree looks more like this:
Py compiler.parse(foo(x=(i for i in range(10
Module(None, Stmt([Discard(CallFunc(Name('foo'), [Keyword('x',
GenExpr(GenExprInner(Name('i'), [GenExprFor(AssName('i', 'OP_ASSIGN'),
CallFunc(Name('range'), [Const(10)], None, None), [])])))], None, None))]))
Cheers,
Nick.
P.S. I added a comment showing the parser output to the SF bug report.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---
http://boredomandlaziness.blogspot.com
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