1 files changed, 56 insertions, 0 deletions
diff --git a/inst/prelude.pl b/inst/prelude.pl
index fefed5f..cc0c940 100644
--- a/inst/prelude.pl
+++ b/inst/prelude.pl
@@ -3,3 +3,59 @@ member(X, [_|T]) :- member(X,T).
 
 append([], X, X).
 append([X|T], Y, [X|TY]) :- append(T,Y,TY).
+
+:- op(700, xfx, is),
+   op(700, xfx, <),
+   op(700, xfx, =<),
+   op(700, xfx, >),
+   op(700, xfx, >=),
+   op(700, xfx, =\=),
+   op(700, xfx, =:=),
+   op(500, yfx, +),
+   op(500, yfx, -),
+   op(500, yfx, /\),
+   op(500, yfx, \/),
+   op(500, yfx, xor),
+   op(400, yfx, *),
+   op(400, yfx, /),
+   op(400, yfx, div),
+   op(400, yfx, mod),
+   op(400, yfx, <<),
+   op(400, yfx, >>),
+   op(200, fy, -),
+   op(200, fy, +).
+
+X is A :- number(A), !, X=A.
+X is V :- var(V), !, stop('variable in arithmetics').
+R is Ax + Bx :- !, A is Ax, B is Bx, int2_add(A, B, R).
+R is Ax - Bx :- !, A is Ax, B is Bx, int2_sub(A, B, R).
+R is Ax * Bx :- !, A is Ax, B is Bx, int2_mul(A, B, R).
+R is Ax / Bx :- !, A is Ax, B is Bx, int2_div(A, B, R).
+R is Ax div Bx :- !, R is Ax / Bx.
+R is Ax mod Bx :- !, A is Ax, B is Bx, int2_mod(A, B, R).
+R is (+Ax) :- !, A is Ax, int1_abs(A, R).
+R is (-Ax) :- !, A is Ax, int1_neg(A, R).
+_ is _ :- stop('arithmetics needs numbers').
+
+Ax =:= Bx :- A is Ax, B is Bx, int2p_eq(A,B).
+Ax =\= Bx :- A is Ax, B is Bx, int2p_neq(A,B).
+Ax < Bx :- A is Ax, B is Bx, int2p_lt(A,B).
+Ax =< Bx :- A is Ax, B is Bx, int2p_leq(A,B).
+Ax > Bx :- A is Ax, B is Bx, int2p_lt(B,A).
+Ax >= Bx :- A is Ax, B is Bx, int2p_leq(B,A).
+zero(Ax) :- A is Ax, int1p_zero(A).
+
+gcd(X,Y,R) :- writeln(a), fail.
+gcd(X,Y,R) :- writeln(b), zero(Y), !, R=X.
+gcd(X,Y,R) :- writeln(c), X1 is X mod Y, gcd(Y,X1,R).
+gcd(X,Y,R) :- writeln(a), Y > X, writeln(wat), !, gcd(Y,X,R).
+gcd(X,Y,R) :- writeln(b), zero(Y), !, R=X.
+gcd(X,Y,R) :- writeln(c), X1 is X mod Y, gcd(Y,X1,R).
+
+test(X) :- writeln(there), zero(X), fail.
+test(X) :- writeln(here).
+
+test :- writeln(a), a=a, !, fail.
+test :- writeln(b).
+
+xxx :- test.