[issue1634034] Show "expected" token on syntax error

Pablo Galindo Salgado added the comment: Closing as per above -- resolution: -> out of date stage: patch review -> resolved status: open -> closed ___ Python tracker ___

[issue1634034] Show "expected" token on syntax error

Terry J. Reedy added the comment: I think that this issue should be closed as 'out of date' as it was pretty open-ended and it is unclear what request remains. For the specific case "for a in (8,9)", the suggested "expected ':'" has been added on another issue. I expect that there are

[issue1634034] Show "expected" token on syntax error

Change by Serhiy Storchaka : -- pull_requests: +6147 stage: needs patch -> patch review ___ Python tracker ___

[issue1634034] Show "expected" token on syntax error

Serhiy Storchaka added the comment: Similar enhancement has been implemented in PyPy just now. https://morepypy.blogspot.de/2018/04/improving-syntaxerror-in-pypy.html -- versions: +Python 3.8 -Python 3.4 ___ Python

[issue1634034] Show expected token on syntax error

Serhiy Storchaka added the comment: I agree, the main problem is in the fact that expected token is not always singular. And even most expected token is a little subjective. The better solution will be to expect several possible tokens. This requires some parser modification. --

[issue1634034] Show expected token on syntax error

Serhiy Storchaka added the comment: Hmm, expected attribute is set when there is only one possible expected token in PyParser_AddToken(). I don't understand why error messages are so misleading for def f(*23): (here not only ')', but a name possible). --

[issue1634034] Show expected token on syntax error

Serhiy Storchaka added the comment: dict(a = i for i in range(10)) +SyntaxError: invalid syntax - ')' expected The () are ok, the message is misleading. dict(a = i) is valid syntax, the compiler expects ) instead of invalid for. 'name' here is a bit vague. The compiler

[issue1634034] Show expected token on syntax error

Ezio Melotti added the comment: I'm not saying that these errors are wrong -- just that they are misleading (i.e. they might lead the user on the wrong path, and make finding the actual problem more difficult). It should be noted that the examples I pasted don't include a full traceback

[issue1634034] Show expected token on syntax error

Changes by Serhiy Storchaka storch...@gmail.com: -- stage: test needed - patch review ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1634034 ___

[issue1634034] Show expected token on syntax error

Serhiy Storchaka added the comment: Patch updated (thanks Benjamin for comments). -- Added file: http://bugs.python.org/file27708/syntax-error-hints-3.4_2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1634034

[issue1634034] Show expected token on syntax error

Ezio Melotti added the comment: Looking at the changes in the patch it seems to me that, in at least a few cases, it's better to have a bare invalid syntax than a misleading error. For example: dict(a = i for i in range(10)) +SyntaxError: invalid syntax - ')' expected The () are ok,

[issue1634034] Show expected token on syntax error

Serhiy Storchaka added the comment: I'm attaching a new version of the patch, based on Dave's (from 2.5 years ago). This patch is against the 3.4. Previous patches contained an error in the message formatting. buf variable out of scope before msg used. Appending '\0' to the format string

[issue1634034] Show expected token on syntax error

Raymond Hettinger rhettin...@users.sourceforge.net added the comment: +1 on the basic idea to make error messages more informative where possible, but am not sure how it would work in any but the more simple cases. How would work in cases where there are multiple possible expected tokens?

[issue1634034] Show expected token on syntax error

Changes by Terry J. Reedy tjre...@udel.edu: -- versions: -Python 2.7 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1634034 ___ ___

[issue1634034] Show expected token on syntax error

Changes by Antoine Pitrou pit...@free.fr: -- nosy: +benjamin.peterson versions: +Python 3.2 -Python 3.1 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1634034 ___

[issue1634034] Show expected token on syntax error

Dave Malcolm dmalc...@redhat.com added the comment: I'm attaching a new version of the patch, based on Oliver's (from 3 years ago). This patch is against the py3k branch. I've introduced a new table of (const) strings: _PyParser_TokenDescs, giving descriptions of each token type, so that you