spurious 'case' parse error

spurious 'case' parse error

[Martijn Dekker]

The following causes a spurious parse error in zsh:

case x in
(x)echo ok ;;
esac

Output:
test.zsh:2: parse error near `ok'

The cause is the lack of space after the ')'; that space should be
optional, but is mandatory in zsh.

Interestingly, this works:

case x in
x)echo ok ;;
esac

Confirmed in zsh 5.0.7 through current git. (I didn't test earlier
versions.)

- Martijn

Re: spurious 'case' parse error

[Bart Schaefer]

On Sep 22,  3:11pm, Martijn Dekker wrote:
}
} case x in
} (x)echo ok ;;
} esac
} 
} Output:
} test.zsh:2: parse error near `ok'
} 
} The cause is the lack of space after the ')'; that space should be
} optional, but is mandatory in zsh.

That's almost certainly happening because

    case xecho in
    (x|y)echo)echo ok;;
    esac

is valid syntax for zsh, so (x)echo is being parsed as a pattern and then
the closing paren is found to be missing.

The space is optional when in sh emulation where grouping syntax is not
allowed in patterns:

    Src/zsh --emulate sh
    $ case x in    
    > (x|y)echo ok;;
    > esac
    echo ok
    $ 

This is probably not going to change, but we'll see what PWS has to say
when he returns from vacation.

Re: spurious 'case' parse error

[Martijn Dekker]

Op 22-09-17 om 16:42 schreef Bart Schaefer:
> That's almost certainly happening because
> 
>     case xecho in
>     (x|y)echo)echo ok;;
>     esac
> 
> is valid syntax for zsh, so (x)echo is being parsed as a pattern and then
> the closing paren is found to be missing.

That makes sense. Also, when zsh is launched as 'sh', the parsing error
does not occur. Report withdrawn. Sorry for the noise!

- M.

Re: spurious 'case' parse error

[Peter Stephenson]

On Fri, 22 Sep 2017 08:42:46 -0700
Bart Schaefer <schaefer@brasslantern.com> wrote:
> That's almost certainly happening because
> 
>     case xecho in
>     (x|y)echo)echo ok;;
>     esac
> 
> is valid syntax for zsh, so (x)echo is being parsed as a pattern and then
> the closing paren is found to be missing.

Yes, without way too much look ahead we couldn't do anything different
in native mode, but nobody's screaming for that anyway.

> The space is optional when in sh emulation where grouping syntax is not
> allowed in patterns:
> 
>     Src/zsh --emulate sh
>     $ case x in    
>     > (x|y)echo ok;;
>     > esac
>     echo ok
>     $ 

Yes, this got fixed up a couple of years ago for increased sh case
compatibility which appears to be doing the right thing so far.

So nothing to do.

pws