Re: Where is this =(:) construct documented?

[Zach Riggle <zachriggle@xxxxxxxxx>]

Formatting fix, I accidentally a newline.

# wat.zsh ####
wat() {
    >&2 echo IN WAT
    >&2 ls -la "$1"
    echo "$1"
}
ls -la $(wat =(:))
#############

Zach Riggle

On Fri, Jun 11, 2021 at 2:17 PM Zach Riggle <zachriggle@xxxxxxxxx> wrote:
>
> It's insane, cool, and I can't find this documented anywhere.  It
> creates a temporary file that is automatically deleted... but only
> after the line / expression terminates.
>
> ( ... ) creates a subshell (terminology?)
> ( : ) creates a subshell that does nothing
> =bash evaluates to the path to bash, e.g. /usr/bin/bash
> $(...) captures the output of a subshell, e.g. x=$(echo foo)
>
> If follows, then, that =(:) shows the path to... what? Apparently, a
> scope-tracked, auto-deleting temporary file.  *Where is this
> documented?*
>
> # wat.zsh ####
> wat() {
>     >&2 echo IN WAT
>     >&2 ls -la "$1"
>     echo "$1"
> }ls -la $(wat =(:))
> #############
>
> # example #####
> $ zsh wat.sh
> IN WAT
> -rw-------  1 zachriggle  wheel  0 Jun 11 14:13 /tmp/zshfMERth
> ls: /tmp/zshfMERth: No such file or directory
> #############
>
> What's more insane is that the temporary file will be auto-populated
> with the output of the =() construct.  Where is THAT documented?
>
> #############
> $ (){ echo $1; cat $1 } =( echo allo )
> /tmp/zshpfFAOp
> allo
> #############
>
>
> Zach Riggle