+:- dynamic(def/2).
% For number_codes/2 we want to just fail if the codes do not represent an integer.
% gprolog.html#number-atom%2F2
:- set_prolog_flag(syntax_error, fail).
+joy(InputString, StackIn, StackOut) :-
+ text_to_expression(InputString, Expression),
+ !,
+ thun(Expression, StackIn, StackOut).
+
+
joy_lex([tok(Token)|Ls]) --> chars(Token), !, joy_lex(Ls).
joy_lex([ lbracket|Ls]) --> "[", !, joy_lex(Ls).
joy_lex([ rbracket|Ls]) --> "]", !, joy_lex(Ls).
joy_term(list(J)) --> [lbracket], !, joy_parse(J), [rbracket].
joy_term(Token) --> [tok(Codes)], {joy_token(Token, Codes)}.
-joy_token(int(I), Codes) :- write(Codes) ,number_codes(I, Codes), !.
+joy_token(int(I), Codes) :- number_codes(I, Codes), !.
joy_token(bool(true), "true") :- !.
joy_token(bool(false), "false") :- !.
joy_token(symbol(S), Codes) :- atom_codes(S, Codes).
blank --> [226, 128, 175].
blank --> [226, 129, 159].
blank --> [227, 128, 128].
+
+
+thun([], S, S).
+thun([Term|E], Si, So) :- thun(Term, E, Si, So).
+
+thun(A, [], S, [A|S]) :- var(A), !.
+thun(A, [T|E], S, So) :- var(A), !, thun(T, E, [A|S], So).
+
+thun(int(A), [], B, [int(A)|B]).
+thun(int(C), [A|B], D, E) :- thun(A, B, [int(C)|D], E).
+
+thun(bool(A), [], B, [bool(A)|B]).
+thun(bool(C), [A|B], D, E) :- thun(A, B, [bool(C)|D], E).
+
+thun(list(A), [], B, [list(A)|B]).
+thun(list(C), [A|B], D, E) :- thun(A, B, [list(C)|D], E).
+
+thun(symbol(A), [], B, C) :- func(A, B, C).
+thun(symbol(A), [C|D], B, F) :- func(A, B, E), thun(C, D, E, F).
+
+thun(symbol(Combo), E, Si, So) :- combo(Combo, Si, S, E, Eo), thun(Eo, S, So).
+
+thun(symbol(D), [], Si, So) :- def(D, [DH| E]), thun(DH, E, Si, So).
+thun(symbol(D), [H|E0], Si, So) :- def(D, [DH|DE]),
+ append(DE, [H|E0], E), /* ................. */ thun(DH, E, Si, So).
+
+% Some error handling.
+
+thun(symbol(Unknown), _, _, _) :-
+ \+ def(Unknown, _),
+ \+ func(Unknown, _, _),
+ \+ combo(Unknown, _, _, _, _),
+ write('Unknown: '),
+ write(Unknown),
+ fail.
+
+
+func(swap, [A, B|S], [B, A|S]).
+func(dup, [A|S], [A, A|S]).
+func(pop, [_|S], S ).
+
+func(cons, [list(A), B |S], [list([B|A])|S]).
+func(concat, [list(A), list(B)|S], [list(C)|S]) :- append(B, A, C).
+
+func(swaack, [list(R)|S], [list(S)|R]).
+func(stack, S , [list(S)|S]).
+func(clear, _ , []).
+func(first, [list([X|_])|S], [ X |S]).
+func(rest, [list([_|X])|S], [list(X)|S]).
+
+func(bool, [ int(0)|S], [bool(false)|S]).
+func(bool, [ list([])|S], [bool(false)|S]).
+func(bool, [bool(false)|S], [bool(false)|S]).
+
+func(bool, [ int(N)|S], [bool(true)|S]) :- N #\= 0.
+func(bool, [list([_|_])|S], [bool(true)|S]).
+func(bool, [ bool(true)|S], [bool(true)|S]).
+
+func( + , [int(A), int(B)|S], [int(A + B)|S]).
+func( - , [int(A), int(B)|S], [int(B - A)|S]).
+func( * , [int(A), int(B)|S], [int(A * B)|S]).
+func( / , [int(A), int(B)|S], [int(B div A)|S]).
+func('%', [int(A), int(B)|S], [int(B mod A)|S]).
+
+func( add , [int(A), int(B)|S], [int(A + B)|S]).
+func( sub , [int(A), int(B)|S], [int(B - A)|S]).
+func( mul , [int(A), int(B)|S], [int(A * B)|S]).
+func( div , [int(A), int(B)|S], [int(B div A)|S]).
+func( mod, [int(A), int(B)|S], [int(B mod A)|S]).
+
+
+combo(i, [list(P)|S], S, Ei, Eo) :- append(P, Ei, Eo).
+combo(dip, [list(P), X|S], S, Ei, Eo) :- append(P, [X|Ei], Eo).
+
+combo(branch, [list(T), list(_), bool(true)|S], S, Ei, Eo) :- append(T, Ei, Eo).
+combo(branch, [list(_), list(F), bool(false)|S], S, Ei, Eo) :- append(F, Ei, Eo).
+
+combo(loop, [list(_), bool(false)|S], S, E, E ).
+combo(loop, [list(B), bool(true)|S], S, Ei, Eo) :- append(B, [list(B), symbol(loop)|Ei], Eo).
+
+
+joy_def(Codes) :-
+ text_to_expression(Codes, [symbol(Name)|Body]),
+ assert_def(Name, Body).
+
+assert_def(Symbol, Body) :-
+ ( % Don't let this "shadow" functions or combinators.
+ \+ func(Symbol, _, _),
+ \+ combo(Symbol, _, _, _, _)
+ ) -> ( % Replace any existing defs of this name.
+ retractall(def(Symbol, _)),
+ assertz(def(Symbol, Body))
+ ) ; true.
+
+joydef("enstacken stack [clear] dip").
\ No newline at end of file