clean up the code a bit

debug.go

@@ -12,7 +12,11 @@ import (
 	"text/tabwriter"
 )
 
-// TODO: delete me
+// debugging tools for dynamo developers
+// disabled by default, use `go build -tags debug` to enable
+// warning: not covered by API stability guarantees
+
+// DumpType dumps a description of x's typedef to stdout.
 func DumpType(x any) {
 	plan, err := typedefOf(reflect.TypeOf(x))
 	if err != nil {

decodefunc.go

@@ -182,7 +182,7 @@ func decodeMap(decodeKey func(reflect.Value, string) error) func(plan *typedef,
 			for name, av := range item {
 				vp := new(V)
 				decodeKey(kp, name)
-				decodeAttr(av, vp) // TODO fix order
+				decodeAttr(av, vp) // TODO: make argument order consistent
 				out[*kp] = *vp
 			}
 	*/

encode.go

@@ -72,7 +72,7 @@ func marshalSliceNoOmit(values []interface{}) ([]*dynamodb.AttributeValue, error
 	return avs, nil
 }
 
-func encodeItem(fields []fieldMeta, rv reflect.Value) (Item, error) {
+func encodeItem(fields []structField, rv reflect.Value) (Item, error) {
 	item := make(Item, len(fields))
 	for _, field := range fields {
 		fv := dig(rv, field.index)

encodefunc.go

@@ -106,6 +106,22 @@ func encodeType(rt reflect.Type, flags encodeFlags) (encodeFunc, error) {
 	return nil, fmt.Errorf("dynamo marshal: unsupported type %s", rt.String())
 }
 
+func encodePtr(rt reflect.Type, flags encodeFlags) (encodeFunc, error) {
+	elem, err := encodeType(rt.Elem(), flags)
+	if err != nil {
+		return nil, err
+	}
+	return func(rv reflect.Value, flags encodeFlags) (*dynamodb.AttributeValue, error) {
+		if rv.IsNil() {
+			if flags&flagNull != 0 {
+				return nullAV, nil
+			}
+			return nil, nil
+		}
+		return elem(rv.Elem(), flags)
+	}, nil
+}
+
 func encode2[T any](fn func(T, encodeFlags) (*dynamodb.AttributeValue, error)) func(rv reflect.Value, flags encodeFlags) (*dynamodb.AttributeValue, error) {
 	target := reflect.TypeOf((*T)(nil)).Elem()
 	interfacing := target.Kind() == reflect.Interface
@@ -133,7 +149,7 @@ func encodeString(rv reflect.Value, flags encodeFlags) (*dynamodb.AttributeValue
 	s := rv.String()
 	if len(s) == 0 {
 		if flags&flagAllowEmpty != 0 {
-			return &dynamodb.AttributeValue{S: &s}, nil
+			return emptyS, nil
 		}
 		if flags&flagNull != 0 {
 			return nullAV, nil
@@ -158,20 +174,40 @@ var encodeTextMarshaler = encode2[encoding.TextMarshaler](func(x encoding.TextMa
 	return &dynamodb.AttributeValue{S: &str}, nil
 })
 
-func encodePtr(rt reflect.Type, flags encodeFlags) (encodeFunc, error) {
-	elem, err := encodeType(rt.Elem(), flags)
-	if err != nil {
-		return nil, err
+func encodeBytes(rt reflect.Type, flags encodeFlags) encodeFunc {
+	if rt.Kind() == reflect.Array {
+		size := rt.Len()
+		return func(rv reflect.Value, flags encodeFlags) (*dynamodb.AttributeValue, error) {
+			if rv.IsZero() {
+				switch {
+				case flags&flagNull != 0:
+					return nullAV, nil
+				case flags&flagAllowEmpty != 0:
+					return emptyB, nil
+				}
+				return nil, nil
+			}
+			data := make([]byte, size)
+			reflect.Copy(reflect.ValueOf(data), rv)
+			return &dynamodb.AttributeValue{B: data}, nil
+		}
 	}
+
 	return func(rv reflect.Value, flags encodeFlags) (*dynamodb.AttributeValue, error) {
 		if rv.IsNil() {
 			if flags&flagNull != 0 {
 				return nullAV, nil
 			}
 			return nil, nil
 		}
-		return elem(rv.Elem(), flags)
-	}, nil
+		if rv.Len() == 0 {
+			if flags&flagAllowEmpty != 0 {
+				return emptyB, nil
+			}
+			return nil, nil
+		}
+		return &dynamodb.AttributeValue{B: rv.Bytes()}, nil
+	}
 }
 
 func encodeStruct(rt reflect.Type) (encodeFunc, error) {