build defs.pl

thun/gnu-prolog/meta-defs.pl

@@ -0,0 +1,40 @@
+/*
+Definitions
+*/
+
+do :- assert_defs(`defs.txt`), print_defs, halt.
+
+joy_def(def(Def, Body)) --> symbol(Def), blanks, "==", joy_parse(Body).
+
+joy_defs --> blanks, joy_def(Def), {assert_def(Def)}, blanks, joy_defs.
+joy_defs --> [].
+
+assert_defs(DefsFile) :-
+    read_file_to_codes(DefsFile, Codes, []),
+    phrase(joy_defs, Codes).
+
+assert_def(def(Def, Body)) :-
+    retractall(def(Def, _)),
+    assertz(def(Def, Body)).
+
+
+
+read_file_to_codes(File, Codes, _) :-
+    open(File, read, Stream),
+    stream_to_codes(Stream, Codes),
+    close(Stream).
+
+
+stream_to_codes(Stream, Codes) :-
+    get_code(Stream, Code),
+    stream_to_codes(Code, Stream, Codes).
+
+stream_to_codes(-1,      _,         []) :- !.
+stream_to_codes(Ch, Stream, [Ch|Codes]) :- stream_to_codes(Stream, Codes).
+
+print_defs :-
+    findall(def(Name, Body), def(Name, Body), List),
+    maplist(print_def, List).
+
+print_def(Def) :- write(Def), write(`.`), nl.
+