In order to learn Prolog, I have implemented the cat
command in Prolog. I want to know if the code is idiomatic and what could be improved.
File args.pl
:
:- module(args, [withFilesOrUserInput/2]).
withFilesOrUserInput(StreamFunction, []) :-
call(StreamFunction, user_input).
withFilesOrUserInput(StreamFunction, [Filename]) :-
withFile(StreamFunction, Filename).
withFilesOrUserInput(StreamFunction, [Head|Tail]) :-
withFile(StreamFunction, Head),
withFilesOrUserInput(StreamFunction, Tail).
withFile(StreamFunction, Filename) :-
open(Filename, read, StreamIn),
call(StreamFunction, StreamIn),
close(StreamIn).
File cat.pl
:
:- use_module(args).
main(Argv) :-
prompt(_, ''),
withFilesOrUserInput(catStream, Argv).
catStream(Stream) :-
copy_stream_data(Stream, user_output),
flush_output(user_output).
Note: I'm using SWI-Prolog.