Slightly more rigourous (and faster!) floating point comparisons usin…

…g ULP. Updated tests/trig.cog to use an 'Almost==' operator

src/runtime.h

@@ -967,9 +967,12 @@ static ptrdiff_t compare_blocks(BLOCK b1, BLOCK b2)
 
 static ptrdiff_t compare_numbers(NUMBER n1, NUMBER n2)
 {
-	double diff = n1 - n2;
-	if (fabs(diff) <= 0.5e-14 * fabs(n1)) return 0;
-	else return diff > 0 ? 1 : -1;
+	// Floating point maths is rather difficult.
+	// This solution is usually better than the naive comparison that most languages use.
+	// But if correctness is important one should implement their own comparison operator.
+	// Def Exact== as ( Let N1 ; Let N2 ; Both <= N1 N2 and <= N2 N1 );
+	ptrdiff_t diff = *(uint64_t*)&n1 - *(uint64_t*)&n2;
+	return diff / 2;
 }
 
 static ptrdiff_t compare_strings(STRING s1, STRING s2)

tests/trig.cog

@@ -1,89 +1,91 @@
-Print If == 1 Sind 90
+Def Almost== as ( Let N ; Let M ; < 0.0000000000001 Abs - N M );
+
+Print If Almost== 1 Sind 90
       "PASS: Degree sin"
 else
       "FAIL: Degree sin";
 
-Print If == 1 Cosd 360
+Print If Almost== 1 Cosd 360
       "PASS: Degree cos"
 else
       "FAIL: Degree cos";
 
-Print If == / Cosd 90 Sind 90 Tand 90
+Print If Almost== / Cosd 90 Sind 90 Tand 90
       "PASS: Degree tan"
 else
       "FAIL: Degree tan";
 
-Print If == 1 Sin / 2 3.14159265358979323846
+Print If Almost== 1 Sin / 2 3.14159265358979323846
       "PASS: Radian sin"
 else
       "FAIL: Radian sin";
 
-Print If == 1 Cos 0
+Print If Almost== 1 Cos 0
       "PASS: Radian cos"
 else
       "FAIL: Radian cos";
 
-Print If == / Cos 90 Sin 90 Tan 90
+Print If Almost== / Cos 90 Sin 90 Tan 90
       "PASS: Radian tan"
 else
       "FAIL: Radian tan";
 
-Print If == 30 Asind 0.5
+Print If Almost== 30 Asind 0.5
       "PASS: Degree arcsin"
 else
       "FAIL: Degree arcsin";
 
-Print If == 60 Acosd 0.5
+Print If Almost== 60 Acosd 0.5
       "PASS: Degree arccos"
 else
       "FAIL: Degree arccos";
 
-Print If == 26.565051177078 Atand 0.5
+Print If Almost== 26.565051177078 Atand 0.5
       "PASS: Degree arctan"
 else
       "FAIL: Degree arctan";
 
-Print If == 0.5235987755983 Asin 0.5
+Print If Almost== 0.5235987755983 Asin 0.5
       "PASS: Radian arcsin"
 else
       "FAIL: Radian arcsin";
 
-Print If == 1.0471975511966 Acos 0.5
+Print If Almost== 1.0471975511966 Acos 0.5
       "PASS: Radian arccos"
 else
       "FAIL: Radian arccos";
 
-Print If == 10 Tan Atan 10
+Print If Almost== 10 Tan Atan 10
       "PASS: Radian arctan"
 else
       "FAIL: Radian arctan";
 
-Print If == 0.17542037193601015 Sinhd 10
+Print If Almost== 0.17542037193601015 Sinhd 10
       "PASS: Degree hyperbolic sin"
 else
       "FAIL: Degree hyperbolic sin";
 
-Print If == 1.0001523125762564 Coshd 1
+Print If Almost== 1.0001523125762564 Coshd 1
       "PASS: Degree hyperbolic cos"
 else
       "FAIL: Degree hyperbolic cos";
 
-Print If == 0.17278206351636377 Tanhd 10
+Print If Almost== 0.17278206351636377 Tanhd 10
       "PASS: Degree hyperbolic tan"
 else
       "FAIL: Degree hyperbolic tan";
 
-Print If == 74.20321057778875 Sinh 5
+Print If Almost== 74.20321057778875 Sinh 5
       "PASS: Radian hyperbolic sin"
 else
       "FAIL: Radian hyperbolic sin";
 
-Print If == 74.20994852478785 Cosh 5
+Print If Almost== 74.20994852478785 Cosh 5
       "PASS: Radian hyperbolic cos"
 else
       "FAIL: Radian hyperbolic cos";
 
-Print If == Tanh 8 / Cosh 8 Sinh 8
+Print If Almost== Tanh 8 / Cosh 8 Sinh 8
       "PASS: Radian hyperbolic tan"
 else
       "FAIL: Radian hyperbolic tan";