Shell (zsh) function for getting the absolute path of its argument

abspath.zsh

function abspath() {
    # generate absolute path from relative path
    # $1     : relative filename
    # return : absolute path
    # From http://stackoverflow.com/a/23002317/514210
    if [[ -d "$1" ]]; then
        # dir
        (cd "$1"; pwd)
    elif [[ -f "$1" ]]; then
        # file
        if [[ $1 == */* ]]; then
            echo "$(cd "${1%/*}"; pwd)/${1##*/}"
        else
            echo "$(pwd)/$1"
        fi
    fi
}