nix-env "default nix expression" / "active nix expression" / top-level

nix-defexpr.zsh

_nix_build_defexpr () {
    local -a result
    local -a queue=($1)
    setopt local_options null_glob
    while [[ ${#queue} > 0 ]]; do
        local current=$queue[1]
        shift queue
        if [[ -e $current/default.nix ]]; then
            result+=($current)
        else
            queue+=($current/*)
        fi
    done

    local nix_expr="{\n"
    for p in $result; do
        nix_expr+="$(basename $p) = import $p {};"
        nix_expr+="\n"
    done
    nix_expr+="}"

    echo $nix_expr
}