This library contains utilities that deal with streams, notably originating from non-built-in sources such as URLs, archives, windows, processes, etc.
The predicate open_any/5 
acts as a broker between applications that can process data from 
a stream and libraries that can create streams from diverse sources. 
Without this predicate, processing data inevitally follows the pattern 
below. As call_some_open_variation can be anything, this blocks 
us from writing predicates such as load_xml(From, DOM) that 
can operate on arbitrary input sources.
setup_call_cleanup(
    call_some_open_variation(Spec, In),
    process(In),
    close(In)).
Libraries that can open streams can install the hook iostream:open_hook/6 to make their functionality available through open_any/5.
Without loaded plugins, the open_any/5 
processes the following values for Specification. If no rule 
matches, open_any/5 
processes Specification as file(Specification).
library(uri) to be installed.
The typical usage scenario is given in the code below, where <process> processes the input.
setup_call_cleanup(
    open_any(Spec, read, In, Close, Options),
    <process>(In),
    Close).
Currently, the following libraries extend this predicate:
http and https 
schemes.
| Close | is unified to a goal that must be 
called to undo the side-effects of the action, e.g., typically the term close(Stream) | 
| Options0 | are the options passed to open_any/5 | 
| Options | are passed to the post processing filters that may be installed by open_any/5. |