drscheme:language:get-default-mixin in DrScheme Tools Functions
(drscheme:language:get-default-mixin) -> ((implementation?/c drscheme:language:language<%>) . ->d . (lambda (%) (subclass?/c %)))
This function can only be called in phase 2.
The result of this function is the composite of all of the
default-implementation arguments passed
to
drscheme:language:extend-language-interface.