do not _invoke_ @configurable functions when defining default arguments in (@configurable) functions

Invoking functions to obtain values for default arguments should NOT be done when those functions are @configurable, i.e. when the arguments of the called function are bindable -- as this way those functions will be invoked pre-maturely, i.e. prior to the relevant bind being executed, resulting in the wrong values being used when the function which calls them is invoked in a way which uses the default values...