with statement odd feature

[buran]

i expected it to throw syntax errors in the compile phase. i guess it compiled the raise in place of them.

look at docs for Compound statements: the with statement

with_stmt ::= "with" with_item ("," with_item)* ":" suite
with_item ::= expression ["as" target]

....
5. If a target was included in the with statement, the return value from __enter__() is assigned to it.

providing target is optional and there is no SyntaxError. Your snippet raise NameError and then the except catch it.


Also in PEP343, Specification: The 'with' Statement:

with EXPR as VAR:
    BLOCK

...

The "as VAR" part is optional.

...

If the "as VAR" part of the syntax is omitted, the "VAR =" part of the translation is omitted (but mgr.__enter__() is still called).