Added types package

src/types/Is.go

@@ -0,0 +1,47 @@
+package types
+
+// Is returns true if the encountered type `a` can be converted into the expected type `b`.
+func Is(a Type, b Type) bool {
+	if a == b || b == Any || a == nil {
+		return true
+	}
+
+	aPointer, aIsPointer := a.(*Pointer)
+	bPointer, bIsPointer := b.(*Pointer)
+
+	if aIsPointer && bIsPointer && (bPointer.To == Any || aPointer.To == bPointer.To) {
+		return true
+	}
+
+	aArray, aIsArray := a.(*Array)
+
+	if aIsArray && bIsPointer && (bPointer.To == Any || aArray.Of == bPointer.To) {
+		return true
+	}
+
+	bArray, bIsArray := b.(*Array)
+
+	if aIsArray && bIsArray && (bArray.Of == Any || aArray.Of == bArray.Of) {
+		return true
+	}
+
+	if a == AnyInt {
+		switch b {
+		case Int64, Int32, Int16, Int8, UInt64, UInt32, UInt16, UInt8, AnyInt:
+			return true
+		default:
+			return false
+		}
+	}
+
+	if b == AnyInt {
+		switch a {
+		case Int64, Int32, Int16, Int8, UInt64, UInt32, UInt16, UInt8, AnyInt:
+			return true
+		default:
+			return false
+		}
+	}
+
+	return false
+}