Jitterbug-Id: 177
Submitted-By: simonb@logical.co.za
Date: Tue, 11 Jan 2000 05:17:37 -0500 (EST)
Version: 1-5-2
OS: NT 4.0


Hi there

I don't know if this is a bug, or is intentional behaviour for a specific
reason.

The following code produces a syntax error about the continue not being within a
looping structure rather than a prefectly silly infinite loop...

while 1:
  try:
    continue
  except:
    pass

where the following works as one would expect...

while 1:
  try:
    raise 1
  except:
    continue

I figure that there is more likely a sane reason for this behaviour than being a
bug, but I am curious.

Thanks
Simon



====================================================================
Audit trail:
Wed Jan 12 18:11:45 2000	guido	changed notes
Wed Jan 12 18:11:45 2000	guido	moved from incoming to request

From: "Tim Peters" <tim_one@email.msn.com>
Subject: RE: [Python-bugs-list] Syntax (PR#177)
Date: Tue, 11 Jan 2000 12:10:17 -0500

[Simon Barratt, putting "continue" in a "try" block]
> I don't know if this is a bug, or is intentional behaviour
> for a specific reason.

Actually, it's a bit of both <wink>.  See the Language Reference Manual's
section on the "continue" statement, particularly the footnote:

    The restriction on occurring in the try clause is
    implementer's laziness and will eventually be lifted.

It's been this way (and documented) forever; it's simply hard to implement
given the current structure of the interpreter loop.

Rest assured there's nothing *conceptually* wrong with putting continue in a
try!  It's simply an implementation restriction; the error msg should
probably make that clearer.  IIRC, JPython doesn't have this restriction.
"Someday" it will get repaired in CPython too.

It's a zero-priority bug (i.e. not likely to be fixed).

Like the bot said, low priority 'to be fixed' bug.

Please do triage on this bug.

Improved exception messages when 'continue' is in a 'try' block, checked in as Python/compile.c revision 2.141.  This still doesn't do the "right thing" by implementing 'continue' in this context, but makes it easier for users to understand the exception.

Added this to PEP 42; closing the bug report.