Bug or misundertanding from my part?

Bug or misundertanding from my part?

[DervishD]

    Hi all :)

    In the ZSH manual for 4.2.5 we can read:

{ TRY-LIST } always { ALWAYS-LIST }
     First execute TRY-LIST.  Regardless of errors, or break, continue,
     or return commands encountered within TRY-LIST, execute
     ALWAYS-LIST.  Execution then continues from the result of the
     execution of TRY-LIST; in other words, any error, or break,
     continue, or return command is treated in the normal way, as if
     ALWAYS-LIST were not present.  The two chunks of code are referred
     to as the `try block' and the `always block'.

    So, this code should print "try list" and "always list", but it
doesn't:

    #!/bin/zsh
    emulate -L zsh

    {
        print "try list"
        return 13
    } always {
        print "always list"
        return 0
    }

    print "What?"

    The code above just prints "try list" and exits with a return
code of "13", but the manual says that the ALWAYS-LIST is executed
"Regardless of [...] return commands encountered [...]". Am I doing
something wrong? I'm a bit puzzled because the above works if I
change 'return 13' for 'false'.

    Thanks a lot in advance :)
    
    Raúl Núñez de Arenas Coronado

-- 
Linux Registered User 88736 | http://www.dervishd.net
http://www.pleyades.net & http://www.gotesdelluna.net
It's my PC and I'll cry if I want to...

Re: Bug or misundertanding from my part?

[Peter Stephenson]

DervishD wrote:
>     Hi all :)
> 
>     In the ZSH manual for 4.2.5 we can read:
> 
> { TRY-LIST } always { ALWAYS-LIST }
>      First execute TRY-LIST.  Regardless of errors, or break, continue,
>      or return commands encountered within TRY-LIST, execute
>      ALWAYS-LIST.  Execution then continues from the result of the
>      execution of TRY-LIST; in other words, any error, or break,
>      continue, or return command is treated in the normal way, as if
>      ALWAYS-LIST were not present.  The two chunks of code are referred
>      to as the `try block' and the `always block'.
> 
>     So, this code should print "try list" and "always list", but it
> doesn't:
> 
>     #!/bin/zsh
>     emulate -L zsh
> 
>     {
>         print "try list"
>         return 13
>     } always {
>         print "always list"
>         return 0
>     }
> 
>     print "What?"
> 
>     The code above just prints "try list" and exits with a return
> code of "13", but the manual says that the ALWAYS-LIST is executed
> "Regardless of [...] return commands encountered [...]". Am I doing
> something wrong? I'm a bit puzzled because the above works if I
> change 'return 13' for 'false'.

You're running this as a script, right?  In that case the returns are treated
as exits, which have an immediate effect.  To treat returns as returns
you need a function.

pws


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Re: Bug or misundertanding from my part?

[DervishD]

    Hi Peter :)

 * Peter Stephenson <pws@csr.com> dixit:
> >     The code above just prints "try list" and exits with a return
> > code of "13", but the manual says that the ALWAYS-LIST is executed
> > "Regardless of [...] return commands encountered [...]". Am I doing
> > something wrong? I'm a bit puzzled because the above works if I
> > change 'return 13' for 'false'.
> You're running this as a script, right?

    Yes.

> In that case the returns are treated
> as exits, which have an immediate effect.

    I know that, but I assumed, from the documentation, that "return"
and "exit" were handled differently in any context (even in scripts).
Couldn't a little note be added to the docs in the last part, where
the warning about "An exit command encountered in try-list [...]"
already exists. I know, I know, every zsh user should take into
account that a return-is-an-exit-in-a-script, OK, but I think that it
would be a good idea to add a little reminder O:)

> To treat returns as returns you need a function.

    OK, thanks for the information :))

    Raúl Núñez de Arenas Coronado

-- 
Linux Registered User 88736 | http://www.dervishd.net
http://www.pleyades.net & http://www.gotesdelluna.net
It's my PC and I'll cry if I want to...