-stdin_to_codes(Codes) :-
- % Pass in and discard atom 'code' to prime stdin_to_codes/2.
- stdin_to_codes(code, [code|Codes]).
-
-stdin_to_codes(-1, []) :- !.
-stdin_to_codes(Code, [Code|Codes]) :-
- get_code(NextCode),
- stdin_to_codes(NextCode, Codes).
+text_to_expression(Text, Expression) :-
+ phrase(joy_lex(Tokens), Text), !,
+ phrase(joy_parse(Expression), Tokens).
-%
-%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_lex(Ls) --> blank, !, joy_lex(Ls).
+joy_lex( Ls ) --> blank, !, joy_lex(Ls).
joy_lex([]) --> [].
-% Then parse the tokens converting them to Prolog values and building up
-% the list structures (if any.)
-
joy_parse([J|Js]) --> joy_term(J), !, joy_parse(Js).
joy_parse([]) --> [].
+
joy_term(list(J)) --> [lbracket], !, joy_parse(J), [rbracket].
-joy_term(Token) --> [tok(Codes)], {joy_token(Token, Codes)}.
+joy_term(Term) --> [tok(Codes)], { joy_term(Term, Codes) }.
-joy_token(int(I), Codes) :- numeric(Codes), atom_codes(I, Codes), !.
-joy_token(bool(true), "true") :- !.
-joy_token(bool(false), "false") :- !.
-joy_token(symbol(S), Codes) :- atom_codes(S, Codes).
-text_to_expression(Text, Expression) :-
- phrase(joy_lex(Tokens), Text), !,
- phrase(joy_parse(Expression), Tokens).
+joy_term( int(I), Codes) :- numeric(Codes), !, atom_codes(I, Codes).
+joy_term( bool(true), "true") :- !.
+joy_term(bool(false), "false") :- !.
+joy_term( symbol(S), Codes) :- atom_codes(S, Codes).
+
% Apologies for all the (green, I hope) cuts. The strength of the Joy
% syntax is that it's uninteresting.
digit(Code) :- between(0'0, 0'9, Code).
+
+% TODO: code golf this into something more efficient.
blank --> [9].
blank --> [10].
blank --> [11].
blank --> [227, 128, 128].
+stdin_to_codes(Codes) :- stdin_to_codes(code, [code|Codes]).
+% Pass in and discard atom 'code' to prime stdin_to_codes/2.
+
+stdin_to_codes(-1, []) :- !.
+stdin_to_codes(Code, [Code|Codes]) :-
+ get_code(NextCode),
+ stdin_to_codes(NextCode, Codes).
+
+
:- initialization((
stdin_to_codes(Codes),
text_to_expression(Codes, Expr),