undefined symbol in ParserGenerator
In pypy/interpreter/pyparser/metaparser.py in get_first on line 233: the name 'symbol' is undefined. I hit this when parsing the python grammar from the 3.1.2 release. Oddly, the current py3k trunk does not hit this. I'll dig more to see if I can figure out why the grammar is causing this, but the error handling here is obviously bogus, so I thought I'd go ahead and report it. -Terrence
2010/4/18 Terrence Cole <list-sink@trainedmonkeystudios.org>:
In pypy/interpreter/pyparser/metaparser.py in get_first on line 233: the name 'symbol' is undefined.
I hit this when parsing the python grammar from the 3.1.2 release. Oddly, the current py3k trunk does not hit this. I'll dig more to see if I can figure out why the grammar is causing this, but the error handling here is obviously bogus, so I thought I'd go ahead and report it.
This is because the 3.1.2 grammar is incorrect, and CPython's parser generator accepts it. See http://svn.python.org/view?view=rev&revision=75080. It's safe to use the py3k branch one, since it hasn't changed. -- Regards, Benjamin
On Sun, 2010-04-18 at 21:13 -0500, Benjamin Peterson wrote:
2010/4/18 Terrence Cole <list-sink@trainedmonkeystudios.org>:
In pypy/interpreter/pyparser/metaparser.py in get_first on line 233: the name 'symbol' is undefined.
I hit this when parsing the python grammar from the 3.1.2 release. Oddly, the current py3k trunk does not hit this. I'll dig more to see if I can figure out why the grammar is causing this, but the error handling here is obviously bogus, so I thought I'd go ahead and report it.
This is because the 3.1.2 grammar is incorrect, and CPython's parser generator accepts it. See http://svn.python.org/view?view=rev&revision=75080. It's safe to use the py3k branch one, since it hasn't changed.
Awesome! You've just saved me a lot of difficult, pointless work. Below is the svn diff I ended up with when testing. -Terrence Index: pypy/interpreter/pyparser/metaparser.py =================================================================== --- pypy/interpreter/pyparser/metaparser.py (revision 73878) +++ pypy/interpreter/pyparser/metaparser.py (working copy) @@ -230,7 +230,8 @@ for label, their_first in overlap_check.iteritems(): for sub_label in their_first: if sub_label in inverse: - raise PgenError("ambiguous symbol %s" % (symbol,)) + raise PgenError("ambiguous symbol at '%s': %s" % (label, + sub_label)) inverse[sub_label] = label self.first[name] = all_labels return all_labels
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Benjamin Peterson -
Terrence Cole