# shellcheck shell=bash
#================================================================
#% SYNOPSIS
#+    current <cmd> [-f <flag>] [-r <regex>]
#%
#% OPTIONS
#%  -f  set command-line args to pass to <cmd>; single string.
#%      Default: [--version]
#%  -r  set regex used to extract version string from cmd output
#%      Default: [v?(\d+\.\d+\.\d+)]
#================================================================
current() {
    flag="--version"
    regex='v?(\d+\.\d+\.\d+)'
    declare -a args
    OPTIND=1
    while [ $OPTIND -le "$#" ]; do
        if getopts :f:r: opt; then
            case "$opt" in
                \?)
                    diag "$(red "error: called 'current' badly")"
                    ;;
                f) flag="$OPTARG" ;;
                r) regex="$OPTARG" ;;
            esac
        else
            args+=("${!OPTIND}")
            (( OPTIND++ ))
        fi
    done
    set -- "${args[@]}"

    cmd="$1"

    if command -v "$cmd" >/dev/null; then
        bash -c "$cmd $flag" | perl -ne 'm/'"$regex"'/ && print "$1\n"' || true
    else
        true
    fi
}