export PATH="${HOME}/.cargo/bin:$PATH"

prepend_path() {
    case ":${PATH:=$1}:" in   # adds the new directory if PATH is empty, returns PATH otherwise
        *:"$1":*)          ;; # already included, don't add to PATH
        *) PATH="$1:$PATH" ;; # prepend the new directory
    esac
}
export GOPATH="$HOME/code/go"

prepend_path "$HOME/.cargo/bin"
prepend_path "$GOPATH/bin"