#!/bin/sh
####
#### Some years ago, I started using ratpoison.  At the time, I used
#### GUI applications, and ratpoison was quite buggy.  Ratpoison would
#### crash, taking the X server and all my GUI apps with it.
####
#### What I needed was a little script that would start ratpoison and
#### then just sit there.  When ratpoison terminated, it would start a
#### new ratpoison process and wait again.  Here it is::
####
####    $@
####    $0 $@
####
#### Sometimes I would exit ratpoison legitimately with the :quit
#### command; I didn't want it to be restarted in that case.  So I
#### modified the program to::
####
####    $@ ||
####    $0 $@
####
#### I noticed that after a few crashes, I had a bunch of sh processes
#### nested like a set of russian dolls.  So I changed it to ::
####
####    $@ ||
####    exec $0 $@
####
#### One time, I managed to make ratpoison crash a few milliseconds
#### after starting (the default font didn't exist).  The loop was too
#### tight; it hogged all the RAM.  I put in a short delay between
#### loops::
####
####    if ! $@
####    then sleep 1
####         exec $0 $@
####    fi
####
#### Then I decided it would be best if it *asked* the user whether or
#### not the program should be restarted.  And here it is:

restartp () {                   # succeeds iff user chooses yes
    t="Run \`$1' again?"
    m="Shell command \`$1' failed with code $2.  Run it again?"
    if [[ -n "$DISPLAY" ]]
    then                        # use X11 popup prompt
       if zenity --version
       then zenity --title="$t" --question --text="$m"
       elif gmessage --version
       then gmessage -buttons Yes:0,No:1 -default Yes "$m"
       elif Xdialog --version
       then Xdialog --title "$t" --yesno "$m" 6 "$(expr length "$m")"
       elif xmessage -help
       then xmessage -buttons Yes:0,No:1 -default Yes "$m"
       else return 0            # give up and assume yes
       fi >/dev/null 2>&1
    elif [[ -t 0 && -t 1 ]]
    then                        # use stdio prompt
       printf "%s [Y/n] " "$m"
       read response
       case "$response" in
           [nN]*) return 1;;
       esac
    else return 0               # assume yes
    fi
}

"$@"                            # run command
case $? in
    0)  exit 0;;                # command succeded
    126)                        # command not executable
        echo >&2 "$0: $1: Permission denied"
        exit 126;;
    127)                        # command not in $PATH
        echo >&2 "$0: $1: command not found"
        exit 127;;
    *)  if restartp "$1" "$?"   # failed; try again?
        then sleep 1
            exec "$0" "$@"
        fi;;
esac