FEAT: included to-degrees and to-radians native functions

related to: Oldes/Rebol-issues#2408

src/core/n-math.c

@@ -490,6 +490,35 @@ enum {SINE, COSINE, TANGENT};
 	return R_ARG1;
 }
 
+/***********************************************************************
+**
+*/	REBNATIVE(to_radians)
+/*
+//	to-radians: native [
+//		"Converts degrees to radians"
+//		degrees [integer! decimal!] "Degrees to convert"
+//	]
+***********************************************************************/
+{
+	REBDEC degrees = AS_DECIMAL(D_ARG(1));
+	SET_DECIMAL(D_RET, degrees * pi1 / 180.0 );
+	return R_RET;
+}
+
+/***********************************************************************
+**
+*/	REBNATIVE(to_degrees)
+/*
+//	to-degrees: native [
+//		"Converts radians to degrees"
+//		radians [integer! decimal!] "Radians to convert"
+//	]
+***********************************************************************/
+{
+	REBDEC radians = AS_DECIMAL(D_ARG(1));
+	SET_DECIMAL(D_RET, radians * 180.0 / pi1 );
+	return R_RET;
+}
 
 /***********************************************************************
 **

src/tests/units/decimal-test.r3

@@ -65,5 +65,26 @@ Rebol [
 	--assert -1.0 = round/half-ceiling -1.5
 
 ===end-group===
+
+===start-group=== "to-degrees & to-radians"
+;@@ https://github.com/Oldes/Rebol-issues/issues/2408
+	--test-- "to-degrees to-radians"
+		foreach [d r] [
+			0   0.0
+			30	0.5235987756
+			45	0.7853981634
+			60	1.0471975512
+			90	1.5707963268
+			120	2.0943951024
+			135	2.3561944902
+			150	2.6179938780
+			180	3.1415926536
+			270	4.7123889804
+			360	6.2831853072
+		][
+			--assert r = round/to r: to-radians d 0.0000000001
+			--assert d = to-degrees r
+		]
+===end-group===
 
 ~~~end-file~~~