FEAT: sqrt native which accepts only decimals

implements: Oldes/Rebol-issues#2433

Author: Oldes

src/core/n-math.c

@@ -301,6 +301,20 @@ enum {SINE, COSINE, TANGENT};
 	return R_RET;
 }
 
+/***********************************************************************
+**
+*/	REBNATIVE(sqrt)
+/*
+//	sqrt: native [
+//		{Returns the square root of a number.}
+//		value [decimal!]
+//	]
+***********************************************************************/
+{
+	SET_DECIMAL(D_RET, sqrt(VAL_DECIMAL(D_ARG(1))));
+	return R_RET;
+}
+
 #endif //!USE_NO_INFINITY
 
 /***********************************************************************

src/tests/units/decimal-test.r3

@@ -122,6 +122,14 @@ Rebol [
 	--test-- "square-root -1"
 	;@@ https://github.com/Oldes/Rebol-issues/issues/2431
 		--assert "1.#NaN" = mold try [square-root -1]
+	--test-- "sqrt"
+	;@@ https://github.com/Oldes/Rebol-issues/issues/2433
+		--assert all [
+			error? e: try [sqrt 4]
+			e/id = 'expect-arg
+			e/arg3 = integer!
+		]
+		--assert 2.0 = sqrt 4.0
 ===end-group===