Re: ``shopt -s extglob'' and ``function @() { true; }''

[Pierre Gaston]

On Fri, Mar 31, 2017 at 7:00 AM, Clark Wang <dearvoid@gmail.com> wrote:

There is a post on stackoverflow: http://stackoverflow.com/questions/43117707/bashs-strange-behavior-on-a-function-named/

The problem:

bash-4.4# shopt -s extglob
bash-4.4# function @() { echo foo; }
bash-4.4# @()
foo
bash-4.4# declare -f
@() ()
{
    echo foo
}
bash-4.4#
bash-4.4# unset -f '@()'
bash-4.4#
bash-4.4# shopt -s nullglob
bash-4.4# function @() { echo foo; }
bash-4.4# @()
bash-4.4# declare -f
@() ()
{
    echo foo
}
bash-4.4#

So when extglob is on, @() is handled as a glob pattern which makes sense. But the behavior after shopt -s nullglob indicates that the glob pattern @() is not filename-expanded for function @(). This looks kind of counter-intuitive to me.

Bug or feature?

-clark

 

​

Since the manual does not document special chars as allowed in function names, it can be whatever :D

"function" is a keyword not a builtin, so it can change the rules of parsing, like trying to parse a function name instead of performing the normal expansions (that's also why you can't do things like  var=foo; function $var { echo foo; } )

 I'm more surprised that @() runs the function at all. (It seems to hang my 4.3 bash here)