From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-users-return-20332-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 7872 invoked by alias); 22 Jul 2015 00:40:12 -0000
Mailing-List: contact zsh-users-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Users List <zsh-users.zsh.org>
List-Post: <mailto:zsh-users@zsh.org>
List-Help: <mailto:zsh-users-help@zsh.org>
X-Seq: 20332
Received: (qmail 19942 invoked from network); 22 Jul 2015 00:40:08 -0000
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW,
	SPF_HELO_PASS autolearn=ham autolearn_force=no version=3.4.0
X-Injected-Via-Gmane: http://gmane.org/
Mail-Followup-To: zsh-users@zsh.org
To: zsh-users@zsh.org
From: Emanuel Berg <embe8573@student.uu.se>
Subject: sound policy on global variables for "distributed" DWIM function
Date: Wed, 22 Jul 2015 02:37:17 +0200
Message-ID: <87fv4hm3ia.fsf@nl106-137-147.student.uu.se>
Mime-Version: 1.0
Content-Type: text/plain
X-Complaints-To: usenet@ger.gmane.org
X-Gmane-NNTP-Posting-Host: nl106-137-97.student.uu.se
Mail-Copies-To: never
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux)
Cancel-Lock: sha1:LCuFirJh3ZuGEtCPWQs9DhaGNOo=

I have put together a DWIM function to take
screenshots (or dumps), and it can be invoked in
X just as well as in the console with the wrapper
detecting which one and acting accordingly.

My question is, you see that the data item ".png"
appears in *both* specialized functions (dump-vt and
dump-x), but it is likely that if I ever were to
abandon PNG for some other format, I'd want that for
dumps both of the VTs and X.

So, do I put that data a global variable (and what is
the best way to do that?), or do I have a function
return that value and thus have two invocations but
only one data item, or do I do something else?

What is the rule of thumb?

Other comments on the code are also appreciated :)

#! /bin/zsh

# This file: http://user.it.uu.se/~embe8573/conf/.zsh/dump

dump-vt () {
    local file=$1.png
    local vt=$2
    case $# in
        (1) fbgrab $file              ;;
        (2) sudo fbgrab -c $vt $file
            sudo chown $USER $file    ;;
    esac
}

dump-emacs () { dump-vt $1 1 } # because Emacs runs in tty1

dump-x () {
    local file=$1.png
    local window_name=$2
    local window_id=`wmctrl -l | grep -i $window_name | cut -d " " -f1`
    case $# in
        (1) sleep 10; xwd -root                         ;;
        (2) wmctrl -a $window_name; xwd -id $window_id  ;;
    esac | convert - $file
}

dump () {
    if [[ $DISPLAY ]]; then
        dump-x $@
    else
        dump-vt $@
    fi
}

-- 
underground experts united
http://user.it.uu.se/~embe8573