Re: About zsh-users 8489 (exception handling)

[Peter Stephenson <pws@xxxxxxx>]

Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx> wrote:
> I think EXCEPTION should also be declared with "typeset -g", so that
> makes the complete function look like:
> 
> throw() {
>   typeset -g EXCEPTION="$1"
>   readonly THROW
>   if (( TRY_BLOCK_ERROR == 0 )); then
>     # We are throwing an exception from the middle of an always-block.
>     # We can do this by restoring the error status from the try-block.
>     # (I am not convinced I ever intended this to work, but it does...)
>     (( TRY_BLOCK_ERROR = 1 ))
>   fi
>   # Raise an error, but don't show an error message.
>   # This is a bit of a hack.  (Surprised?)
>   THROW= 2>/dev/null
> }

How about this...

Index: Doc/Zsh/contrib.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/contrib.yo,v
retrieving revision 1.47
diff -u -r1.47 contrib.yo
--- Doc/Zsh/contrib.yo	22 Sep 2005 22:23:45 -0000	1.47
+++ Doc/Zsh/contrib.yo	28 Sep 2005 15:16:36 -0000
@@ -1284,8 +1284,8 @@
 In common with exception handling in other languages, the exception may be
 thrown by code deeply nested inside the `try' block.  However, note that it
 must be thrown inside the current shell, not in a subshell forked for a
-pipline, parenthesised current-shell construct, or some form of
-substitution.
+pipeline, parenthesised current-shell construct, or some form of
+command or process substitution.
 
 The system internally uses the shell variable tt(EXCEPTION) to record the
 name of the exception between throwing and catching.  One drawback of this
Index: Functions/Exceptions/throw
===================================================================
RCS file: /cvsroot/zsh/zsh/Functions/Exceptions/throw,v
retrieving revision 1.1
diff -u -r1.1 throw
--- Functions/Exceptions/throw	15 Feb 2005 18:32:38 -0000	1.1
+++ Functions/Exceptions/throw	28 Sep 2005 15:16:36 -0000
@@ -19,11 +19,12 @@
 # script.
 
 # The following must not be local.
-EXCEPTION="$1"
+typeset -g EXCEPTION="$1"
+readonly THROW
 if (( TRY_BLOCK_ERROR == 0 )); then
   # We are throwing an exception from the middle of an always-block.
   # We can do this by restoring the error status from the try-block.
   (( TRY_BLOCK_ERROR = 1 ))
 fi
 # Raise an error, but don't show an error message.
-{ ${:?THROW} } 2>/dev/null
+THROW= 2>/dev/null



-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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