Re: [Help-bash] make function local

[Linda Walsh]

Greg Wooledge wrote:
> The problem is, ALL function definitions (and un-definitions) are global.
---
yeah...
> If there was a "func" defined at the global scope, you've obliterated it.
> I don't understand why you don't understand this.
---
        I don't understand why you think I don't understand this.

	I showed an example where I wanted to use a local function in 
a stand-alone script -- there were no libraries involved.  There was 
no previous definition.  The function was deleted if it was called
once.  No other interactions were specified.

        I don't get why you toss in all sorts of other possible interactions
that I didn't specify nor that existed.  Sure, if I pull the plug from
the wall all of your examples on your website won't work.  So should
I question your examples because they don't work under all possible
circumstances?  That's ridiculous.  


> Doing trickery to make it LOOK LIKE you have a local function just leads
> to confusion.  The person who inherits this script from you after you're
> gone may think the function is local, when it isn't.
---
        I'm quite clear about how I use "throw-away" functions.

> So, what is the point of doing this convoluted trickery, when it
> accomplishes nothing (it doesn't create a local function, and it doesn't
> prevent contamination of the global function namespace)?  Just to
> see how "clever" you can be?
---
        No, as an example where a local function would be of use --
and the "clever trickery" (I said it as a "trite example") involved.


        If I wanted clever trickery, I'd use a function generator
that generated function names with a GUID ending -- then test if that
exists and repeat if there is a collision.  That would be more my idea
of clever trickery, since "Guids" are considered to be "Globally Unique"
(even though they really aren't), it would be as solid as a true local
functions as much as GUIDS are really globally unique -- sorta something
like:

sub uuid_name {
 my uuid=$(uuidgen)
 echo "${uuid//-/_}"
}

sub filterarray {
 my arrayname=${1:?}
 my filter=${2:?}
 my t=$(type -t "$filter")
 if [[ $t!=function && $t!=alias ]]; then
   my uname="F_$(uuid_name)"
   eval "sub $uname { $filter }"
 fi
}
---
Would be more my idea of "clever trickery" -- and would be just
as globally unique as GUID's are taken to be (regen GUID's until
you find one that doesn't collide (note the above code doesn't
loop on a test, but was a random scriplet written a year ago
to capture the idea of wrapping some 'filter' code in a sub
if it wasn't already an alias or a sub.

Of course, I'm sure you already thought of creating function
names on the fly using GUID's to ensure they don't collide
globally, tricky guy that you are...  ;-)