1 files changed, 76 insertions, 0 deletions
diff --git a/loader.pl b/loader.pl
new file mode 100644
index 0000000..3ba1c05
--- /dev/null
+++ b/loader.pl
@@ -0,0 +1,76 @@
+:- module(loader, []).
+
+load_module_from_file(File) :-
+	write('Loading file: '),
+	write(File),
+	nl,
+	( atom_concat(_, '.pl', File)
+	-> open(File, read, Stream)
+	; atom_concat(File, '.pl', File1),
+	  open(File1, read, Stream)
+	),
+	read_and_handle_terms(Stream, user, _),
+	close(Stream),
+	write('Loaded file: '),
+	write(File),
+	nl.
+
+read_and_handle_terms(Stream, Module0, Module) :-
+	( read_one_term(Stream, Term)
+	-> handle_term(Term, Module0, Module1),
+	   read_and_handle_terms(Stream, Module1, Module)
+	; Module = Module0
+	).
+
+read_one_term(Stream, Term) :-
+	consume_whitespace(Stream),
+	peek_char(Stream, NextCh),
+	NextCh \= end_of_file,
+	read_term(Stream, Term, []).
+
+whitespace(' ').
+whitespace('	').
+whitespace('
+').
+
+consume_whitespace(S) :-
+	peek_char(S, Ch),
+	( whitespace(Ch)
+	-> get_char(S, _), consume_whitespace(S)
+	; true
+	).
+
+handle_term(:- Directive, Module, NewModule) :-
+	!,
+	handle_directive(Directive, Module, NewModule).
+handle_term(Head :- Body, Module, Module) :-
+	!,
+	Module:assertz(Head :- Body).
+handle_term(Head --> Body, Module, Module) :-
+	!,
+	write('DCG RULE: '),
+	write(Head --> Body),
+	nl.
+handle_term(Head, Module, Module) :-
+	Module:assertz(Head).
+
+handle_directive(op(Priority, Specifier, Operator), Module, Module) :-
+	Module:op(Priority, Specifier, Operator).
+handle_directive(include(F), Module, NewModule) :-
+	open(F, read, S),
+	read_and_handle_terms(S, Module, NewModule),
+	close(S).
+handle_directive(ensure_loaded(F), Module, Module) :-
+	ensure_load(F).
+handle_directive(D, Module, Module) :-
+	write('Cannot handle directive: '),
+	write(D),
+	nl.
+
+ensure_loads(_) :- fail.
+
+ensure_load(F) :-
+	( ensure_loads(F)
+	-> true
+	; asserta(ensure_loads(F)), load_module_from_file(F)
+	).