Zsh will not parse an autoload function when it has short loops

Zsh will not parse an autoload function when it has short loops

[Sebastian Gniazdowski]

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Hello

I've created autoload function "bug" in /usr/share/zsh/.../functions, and
when run, it gives:

bug:9: parse error near `list[$i]'

Adding echo's to the file and changing various things revealed no reaction.
This means that the file isn't actually run by zsh - apparently the message
comes from some initial parsing stage.

Here is the file:

emulate -L zsh

setopt localoptions typesetsilent localtraps extendedglob shortloops

while (( 1 )); do
    # No influence, the code isn't run at all
    # typeset -a VLIST_NONSELECTABLE_ELEMENTS
    if [ ! -z "$VLIST_SEARCH_BUFFER" ]; then
        [ "$#VLIST_NONSELECTABLE_ELEMENTS" -gt 0 ] && for i
("${(nO)VLIST_NONSELECTABLE_ELEMENTS[@]}") list[$i]=()
    fi

done

Re: Zsh will not parse an autoload function when it has short loops

[Mikael Magnusson]

On Fri, Aug 28, 2015 at 8:39 AM, Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
> Hello
>
> I've created autoload function "bug" in /usr/share/zsh/.../functions, and
> when run, it gives:
>
> bug:9: parse error near `list[$i]'
>
> Adding echo's to the file and changing various things revealed no reaction.
> This means that the file isn't actually run by zsh - apparently the message
> comes from some initial parsing stage.
>
> Here is the file:
>
> emulate -L zsh
>
> setopt localoptions typesetsilent localtraps extendedglob shortloops
>
> while (( 1 )); do
>     # No influence, the code isn't run at all
>     # typeset -a VLIST_NONSELECTABLE_ELEMENTS
>     if [ ! -z "$VLIST_SEARCH_BUFFER" ]; then
>         [ "$#VLIST_NONSELECTABLE_ELEMENTS" -gt 0 ] && for i
> ("${(nO)VLIST_NONSELECTABLE_ELEMENTS[@]}") list[$i]=()
>     fi
>
> done

This is expected, the shortloops option affects parsing of files. As
you noticed the code is not run, only parsed, so therefore the setopt
shortloops inside the function has no effect, but you use shortloops
syntax which means it has to be on when you parse it. Long story
short: don't use shortloops syntax in portable code.

-- 
Mikael Magnusson

Re: Zsh will not parse an autoload function when it has short loops

[Bart Schaefer]

On Aug 28,  8:43am, Mikael Magnusson wrote:
} Subject: Re: Zsh will not parse an autoload function when it has short loo
}
} On Fri, Aug 28, 2015 at 8:39 AM, Sebastian Gniazdowski
} <sgniazdowski@gmail.com> wrote:
} > Hello
} >
} > I've created autoload function "bug" in /usr/share/zsh/.../functions, and
} > when run, it gives:
} >
} > bug:9: parse error near `list[$i]'
} 
} This is expected, the shortloops option affects parsing of files.

There's a straightforward workaround for this:  Instead of

    autoload shortloopfn

use

    emulate zsh -c 'autoload shortloopfn'

then zsh emulation scope will be in effect when the function is called,
and everything will parse as expected during loading.

However, it appears "autoload +X" does not respect the emulation options
put into effect at the time the function was originally marked for
autoloading.  I can't decide whether that is a bug.  The reason that the
"autoload -c" trick works is because the function ends up being defined
approximately as

    shortloopfn() {
       emulate zsh	# "sticky emulation"
       autoload -X shortloopfn
    }

so the emulation is restored before the load, and obviously this is not
equivalent to "autoload +X" run explicitly.

-- 
Barton E. Schaefer