feat: parse into a Document that keeps order and comments

Assisted-by: DeepSeek V4.1 Flash

cmd/interpres-decode/main.go

@@ -67,7 +67,7 @@ func Run(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 		fmt.Fprintln(stderr, "read stdin:", err)
 		return 2
 	}
-	tree, err := interpres.Parse(data)
+	tree, err := interpres.ParseMap(data)
 	if err != nil {
 		fmt.Fprintln(stderr, err)
 		return 1
@@ -108,7 +108,7 @@ func validatePaths(paths []string, stdin io.Reader, stderr io.Writer) int {
 			fmt.Fprintf(stderr, "interpres-decode: %s: %v\n", name, err)
 			return 2
 		}
-		if _, err := interpres.Parse(data); err != nil {
+		if _, err := interpres.ParseMap(data); err != nil {
 			fmt.Fprintf(stderr, "%s: %v\n", name, err)
 			valid = false
 		}
@@ -262,7 +262,7 @@ func decodeTagged(typ, val string) (any, error) {
 // parser and requiring the result to hold exactly that one statement, so a
 // value carrying a newline or a comment cannot smuggle a second one in.
 func parseAtom(val string) (any, error) {
-	tree, err := interpres.Parse([]byte("v = " + val + "\n"))
+	tree, err := interpres.ParseMap([]byte("v = " + val + "\n"))
 	if err != nil {
 		return nil, err
 	}