[Python-checkins] commit of r41743 - in python/trunk: Doc/ref/ref7.tex Misc/NEWS

Sat Dec 17 23:24:13 CET 2005

Author: neal.norwitz
Date: Sat Dec 17 23:24:12 2005
New Revision: 41743
Modified:
 python/trunk/Doc/ref/ref7.tex
 python/trunk/Misc/NEWS
Log:
Doc for PEP 341, needs improvement
Modified: python/trunk/Doc/ref/ref7.tex
==============================================================================

--- python/trunk/Doc/ref/ref7.tex	(original)
+++ python/trunk/Doc/ref/ref7.tex	Sat Dec 17 23:24:12 2005
@@ -195,26 +195,25 @@
 code for a group of statements:
 
 \begin{productionlist}
- \production{try_stmt}
- {\token{try_exc_stmt} | \token{try_fin_stmt}}
- \production{try_exc_stmt}
+ \production{try_stmt} {try1_stmt | try2_stmt}
+ \production{try1_stmt}
 {"try" ":" \token{suite}}
 \productioncont{("except" [\token{expression}
 ["," \token{target}]] ":" \token{suite})+}
 \productioncont{["else" ":" \token{suite}]}
- \production{try_fin_stmt}
- {"try" ":" \token{suite}
- "finally" ":" \token{suite}}
+ \productioncont{["finally" ":" \token{suite}]}
+ \production{try2_stmt}
+ {"try" ":" \token{suite}}
+ \productioncont{"finally" ":" \token{suite}}
 \end{productionlist}
 
-There are two forms of \keyword{try} statement:
-\keyword{try}...\keyword{except} and
-\keyword{try}...\keyword{finally}. These forms cannot be mixed (but
-they can be nested in each other).
-
-The \keyword{try}...\keyword{except} form specifies one or more
-exception handlers
-(the \keyword{except} clauses). When no exception occurs in the
+\versionchanged[In previous versions of Python,
+\keyword{try}...\keyword{except}...\keyword{finally} did not work.
+\keyword{try}...\keyword{except} had to be nested in
+\keyword{try}...\keyword{finally}]{2.5}
+
+The \keyword{except} clause(s) specify one or more exception handlers.
+When no exception occurs in the
 \keyword{try} clause, no exception handler is executed. When an
 exception occurs in the \keyword{try} suite, a search for an exception
 handler is started. This search inspects the except clauses in turn until
@@ -232,6 +231,8 @@
 
 If no except clause matches the exception, the search for an exception
 handler continues in the surrounding code and on the invocation stack.
+\footnote{The exception is propogated to the invocation stack only if
+there is no \keyword{finally} clause that negates the exception.}
 
 If the evaluation of an expression in the header of an except clause
 raises an exception, the original search for a handler is canceled
@@ -277,12 +278,13 @@
 \stindex{break}
 \stindex{continue}
 
-The \keyword{try}...\keyword{finally} form specifies a `cleanup' handler. The
-\keyword{try} clause is executed. When no exception occurs, the
-\keyword{finally} clause is executed. When an exception occurs in the
-\keyword{try} clause, the exception is temporarily saved, the
-\keyword{finally} clause is executed, and then the saved exception is
-re-raised. If the \keyword{finally} clause raises another exception or
+If \keyword{finally} is present, it specifies a `cleanup' handler. The
+\keyword{try} clause is executed, including any \keyword{except} and
+\keyword{else} clauses. If an exception occurs in any of the clauses
+and is not handled, the exception is temporarily saved. The
+\keyword{finally} clause is executed. If there is a saved exception,
+it is re-raised at the end of the \keyword{finally} clause.
+If the \keyword{finally} clause raises another exception or
 executes a \keyword{return} or \keyword{break} statement, the saved
 exception is lost. A \keyword{continue} statement is illegal in the
 \keyword{finally} clause. (The reason is a problem with the current
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Sat Dec 17 23:24:12 2005
@@ -14,7 +14,7 @@
 
 - Implementation of PEP 341 - Unification of try/except and try/finally.
 "except" clauses can now be written together with a "finally" clause in
- one try statement instead of two nested ones.
+ one try statement instead of two nested ones. Patch #1355913.
 
 - Bug #1379994: Builtin unicode_escape and raw_unicode_escape codec
 now encodes backslash correctly.
