module Modspace

# File lib/modspace.rb, line 12
def def_mod(*args, in_namespace: Object, in_class_of_instance: nil)
    normalised_args = expand_any_double_colon_namespace_args(args)

    parent_namespace = if !in_class_of_instance.nil?
        in_class_of_instance.class
    elsif !in_namespace.nil? # :in_namespace can be a module or class
        in_namespace
    else
        raise ArgumentError, "If in_class or for_instance non-nil is specified they must be non-nil."
    end

    defp_class_mod(parent_namespace, *normalised_args)
end

# File lib/modspace.rb, line 28
def defp_class_mod(parent_namespace, *args)
    nesting_list = *args

    return parent_namespace if nesting_list.empty?

    desired_nested_module_name = nesting_list.shift # mutates nested list (but it's local-only)

    # The desired nested module name may have already been defined elsewhere in the overall Ruby codebase.
    # If this is the case, we just reuse that constant definition.
    #
    # Note 1: if we don't do this then we will get the warning: "already initialized constant Foo"
    #
    # Note 2: The false passed to const_defined?() and const_get() methods prevent Ruby from looking up the
    # inheritance tree when searching for the desired nested module name.
    desired_nested_module = if parent_namespace.const_defined?(desired_nested_module_name, false)
        parent_namespace.const_get(desired_nested_module_name, false)
    else
        parent_namespace.const_set(desired_nested_module_name, Module.new)
    end

    defp_class_mod(desired_nested_module, *nesting_list)
end

# File lib/modspace.rb, line 52
def expand_any_double_colon_namespace_args(args_arr)
    args_arr.map{|arg| arg.split('::') }.flatten
end