Re: Higher order functions in zsh (article link)

[Phil Pennock <zsh-workers+phil.pennock@xxxxxxxxxxxx>]

On 2013-03-07 at 11:59 -0500, Christopher Browne wrote:
> cbbrowne@cbbrowne /tmp/maptest> function map {
>     local func_name=$1
>     shift
>     for elem in $@; print -- $(eval $func_name "${elem}")
> }
> 
> But somewhat curiously that doesn't help :-(.

Why does this code have an eval in there?  It's:
 (1) breaking the f3 example
 (2) introducing a security flaw

Hint:  touch 'f4 `mkdir snert`'

This works fine:
----------------------------8< cut here >8------------------------------
function map {
	local func_name=$1
	shift
	for elem in "$@"; print -- $($func_name "${elem}") 
}
----------------------------8< cut here >8------------------------------

With the eval in there, with { map echo * } f3 loses the quotes and f4
just shows "f4" and creates a new sub-directory, snert.

Lose the eval and things work, no new security hole.

Oh, and you need to quote the $@ to "$@" if you want to preserve empty
elements -- whether you do or not depends on what you're mapping across,
but I tend to think "present but empty" is distinct from "not present".

-Phil