implement filter codec

pkg/utils/pointers/pointers.go

@@ -0,0 +1,23 @@
+package pointers
+
+import (
+	"time"
+
+	"next.orly.dev/pkg/encoders/timestamp"
+)
+
+// PointerToValue is a generic interface (type constraint) to refer to any
+// pointer to almost any kind of common type of value.
+//
+// see the utils/values package for a set of methods to accept these values and
+// return the correct type pointer to them.
+type PointerToValue interface {
+	~*uint | ~*int | ~*uint8 | ~*uint16 | ~*uint32 | ~*uint64 | ~*int8 | ~*int16 | ~*int32 |
+		~*int64 | ~*float32 | ~*float64 | ~*string | ~*[]string | ~*time.Time | ~*time.Duration |
+		~*[]byte | ~*[][]byte | ~*timestamp.T
+}
+
+// Present determines whether there is a value for a PointerToValue type.
+func Present[V PointerToValue](i V) bool {
+	return i != nil
+}