stream(Input) option. The hook must be
defined in the module user.
This can be used to load from unusual places as well as dealing with
Prolog code that is not represented as a Prolog source text (for example
some binary representation). For example, library library(http/http_load)
loads Prolog directly from an HTTP server. See also
prolog:open_source_hook/3,
which merely allows for changing how a physical file is opened.