#!/bin/bash
# no bashisms so it can be used in debian profile run by dash
# --start adds to start of path, which will give it highest priority
# --ifexists will add to path only if the directory exists
path_add() {
    local found x y z ifexists start loop
    ifexists=false
    start=false
    loop=true
    # portable substring matching is ugly http://mywiki.wooledge.org/BashFAQ/041
    while $loop; do
        case $1 in
            --*)
                if [ "$1" = --start ]; then
                    start=true
                elif [ "$1" = --ifexists ]; then
                    ifexists=true
                fi
                shift
                ;;
            *)
                loop=false
                ;;
        esac
    done
    for x in "$@"; do
        found=false
        IFS=:
        for y in $PATH; do
            [ "$x" = "$y" ] && found=true
        done
        unset IFS
        if ! $found; then
            if ! $ifexists || [ -d "$x" ]; then
                if [ ! "$PATH" ]; then
                    PATH="$x"
                elif $start; then
                    PATH="$x:$PATH"
                else
                    PATH="$PATH:$x"
                fi
            fi
        fi
    done
}