toPreserves: unpack preservesTupleTail on records

preserves.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version = "20240116"
+version = "20240118"
 author        = "Emery Hemingway"
 description   = "data model and serialization format"
 license       = "Unlicense"

src/preserves.nim

@@ -417,9 +417,13 @@ proc toPreserves*[T](x: T): Value {.gcsafe.} =
           hasVariant = true
     elif T.hasCustomPragma(preservesRecord):
       result = Value(kind: pkRecord)
-      for k, v in x.fieldPairs:
-        var pr = fieldToPreserve(k, v)
-        result.record.add(pr)
+      for label, field in x.fieldPairs:
+        when x.dot(label).hasCustomPragma(preservesTupleTail):
+          for e in field.items:
+            result.record.add(toPreserves(e))
+        else:
+          var pr = fieldToPreserve(label, field)
+          result.record.add(pr)
       result.record.add(toSymbol(T.getCustomPragmaVal(preservesRecord)))
     elif T.hasCustomPragma(preservesTuple):
       result = initSequence(0)