diff --git a/preserves.nimble b/preserves.nimble
index 29d948f..0f5f150 100644
--- a/preserves.nimble
+++ b/preserves.nimble
@@ -1,6 +1,6 @@
 # Package
 
-version = "20230514"
+version = "20230516"
 author        = "Emery Hemingway"
 description   = "data model and serialization format"
 license       = "Unlicense"
diff --git a/src/preserves/preserves_schema_nim.nim b/src/preserves/preserves_schema_nim.nim
index 44b64d0..f4fa01f 100644
--- a/src/preserves/preserves_schema_nim.nim
+++ b/src/preserves/preserves_schema_nim.nim
@@ -116,23 +116,23 @@ proc ident(`ref`: Ref): PNode =
 proc deref(loc: Location; r: Ref): (Location, Definition) =
   result[0] = loc
   if r.module == @[]:
-    result[1] = loc.bundle.modules[loc.schemaPath].data.definitions[r.name]
+    result[1] = loc.bundle.modules[loc.schemaPath].field0.definitions[r.name]
   else:
     result[0].schemaPath = r.module
-    result[1] = loc.bundle.modules[r.module].data.definitions[r.name]
+    result[1] = loc.bundle.modules[r.module].field0.definitions[r.name]
 
 proc hasEmbeddedType(scm: Schema): bool =
-  case scm.data.embeddedType.orKind
+  case scm.field0.embeddedType.orKind
   of EmbeddedtypenameKind.false: false
   of EmbeddedtypenameKind.Ref: true
 
 proc embeddedIdentString(scm: Schema): string =
-  case scm.data.embeddedType.orKind
+  case scm.field0.embeddedType.orKind
   of EmbeddedtypenameKind.false:
     "E"
   of EmbeddedtypenameKind.Ref:
-    doAssert $scm.data.embeddedType.ref.name != ""
-    $scm.data.embeddedType.ref.name
+    doAssert $scm.field0.embeddedType.ref.name != ""
+    $scm.field0.embeddedType.ref.name
 
 proc embeddedIdent(scm: Schema): PNode =
   ident(embeddedIdentString(scm))
@@ -213,8 +213,8 @@ proc attrs(loc: Location; pat: Pattern; seen: RefSet): Attributes =
     attrs(loc, pat.compoundPattern, seen)
 
 proc attrs(loc: Location; orDef: DefinitionOr; seen: RefSet): Attributes =
-  result = attrs(loc, orDef.data.pattern0, seen) + attrs(loc, orDef.data.pattern1, seen)
-  for p in orDef.data.patternN:
+  result = attrs(loc, orDef.field0.pattern0, seen) + attrs(loc, orDef.field0.pattern1, seen)
+  for p in orDef.field0.patternN:
     result = result + attrs(loc, p, seen)
 
 proc attrs(loc: Location; def: Definition; seen: RefSet): Attributes =
@@ -222,9 +222,9 @@ proc attrs(loc: Location; def: Definition; seen: RefSet): Attributes =
   of DefinitionKind.or: result = attrs(loc, def.or, seen)
   of DefinitionKind.and:
     result =
-      attrs(loc, def.and.data.pattern0, seen) +
-      attrs(loc, def.and.data.pattern1, seen)
-    for p in def.and.data.patternN:
+      attrs(loc, def.and.field0.pattern0, seen) +
+      attrs(loc, def.and.field0.pattern1, seen)
+    for p in def.and.field0.patternN:
       result = result + attrs(loc, p, seen)
   of DefinitionKind.Pattern:
     result = attrs(loc, def.pattern, seen)
@@ -277,8 +277,8 @@ proc isSimple(pat: Pattern): bool =
 proc isLiteral(loc: Location; na: NamedAlternative): bool = isLiteral(loc, na.pattern)
 
 proc isSymbolEnum(loc: Location; orDef: DefinitionOr): bool =
-  result = isLiteral(loc, orDef.data.pattern0) and isLiteral(loc, orDef.data.pattern1)
-  for na in orDef.data.patternN:
+  result = isLiteral(loc, orDef.field0.pattern0) and isLiteral(loc, orDef.field0.pattern1)
+  for na in orDef.field0.patternN:
     if not result: break
     result = isLiteral(loc, na)
 
@@ -351,7 +351,7 @@ proc typeIdent(loc: Location; sp: SimplePattern): TypeSpec =
     result = TypeSpec(node: ident(sp.ref), attrs: attrs(loc, sp))
     result.node = parameterize(scm, result)
   of SimplepatternKind.embedded:
-    case scm.data.embeddedType.orKind
+    case scm.field0.embeddedType.orKind
     of EmbeddedtypenameKind.false:
       result = typeIdent(loc, sp.embedded.interface)
     of EmbeddedtypenameKind.Ref:
@@ -613,9 +613,9 @@ proc nimTypeOf(loc: Location; known: var TypeTable; orDef: DefinitionOr; name: s
     let ty = nkEnumTy.newNode.add newEmpty()
     proc add (na: NamedAlternative) =
       ty.add na.variantLabel.ident.accQuote
-    add(orDef.data.pattern0)
-    add(orDef.data.pattern1)
-    for na in orDef.data.patternN:
+    add(orDef.field0.pattern0)
+    add(orDef.field0.pattern1)
+    for na in orDef.field0.patternN:
       add(na)
     ty
   if isSymbolEnum(loc, orDef):
@@ -664,9 +664,9 @@ proc nimTypeOf(loc: Location; known: var TypeTable; orDef: DefinitionOr; name: s
         nn(nkDotExpr,
           enumIdent, na.variantLabel.ident.accQuote),
         branchRecList)
-    addCase(orDef.data.pattern0)
-    addCase(orDef.data.pattern1)
-    for na in orDef.data.patternN: addCase(na)
+    addCase(orDef.field0.pattern0)
+    addCase(orDef.field0.pattern1)
+    for na in orDef.field0.patternN: addCase(na)
     result.node = nn(nkObjectTy,
       newEmpty(),
       newEmpty(),
@@ -725,20 +725,20 @@ proc collectRefImports(imports: var StringSet; loc: Location; pat: Pattern) =
 proc collectRefImports(imports: var StringSet; loc: Location; def: Definition) =
   case def.orKind
   of DefinitionKind.or:
-    collectRefImports(imports, loc, def.or.data.pattern0.pattern)
-    collectRefImports(imports, loc, def.or.data.pattern1.pattern)
-    for na in def.or.data.patternN:
+    collectRefImports(imports, loc, def.or.field0.pattern0.pattern)
+    collectRefImports(imports, loc, def.or.field0.pattern1.pattern)
+    for na in def.or.field0.patternN:
       collectRefImports(imports, loc, na.pattern)
   of DefinitionKind.and:
-    collectRefImports(imports, loc, def.and.data.pattern0.pattern)
-    collectRefImports(imports, loc, def.and.data.pattern1.pattern)
-    for np in def.and.data.patternN:
+    collectRefImports(imports, loc, def.and.field0.pattern0.pattern)
+    collectRefImports(imports, loc, def.and.field0.pattern1.pattern)
+    for np in def.and.field0.patternN:
       collectRefImports(imports, loc, np.pattern)
   of DefinitionKind.Pattern:
     collectRefImports(imports, loc, def.pattern)
 
 proc collectRefImports(imports: var StringSet; loc: Location; scm: Schema) =
-  for _, def in scm.data.definitions:
+  for _, def in scm.field0.definitions:
     collectRefImports(imports, loc, def)
 
 proc mergeType(x: var PNode; y: PNode) =
@@ -760,7 +760,7 @@ proc renderNimBundle*(bundle: Bundle): Table[string, string] =
       typeSection = newNode nkTypeSection
       procs: seq[PNode]
       unembeddableType, embeddableType: PNode
-    for name, def in scm.data.definitions.pairs:
+    for name, def in scm.field0.definitions.pairs:
       if isLiteral(loc, def):
         generateConstProcs(procs, scm, string name, def)
       else:
diff --git a/src/preserves/schema.nim b/src/preserves/schema.nim
index 69dd44d..4fc1e81 100644
--- a/src/preserves/schema.nim
+++ b/src/preserves/schema.nim
@@ -130,21 +130,21 @@ type
   
   DefinitionKind* {.pure.} = enum
     `or`, `and`, `Pattern`
-  DefinitionOrData* {.preservesTuple.} = ref object
+  DefinitionOrField0* {.preservesTuple.} = ref object
     `pattern0`*: NamedAlternative
     `pattern1`*: NamedAlternative
     `patternN`* {.preservesTupleTail.}: seq[NamedAlternative]
 
   DefinitionOr* {.preservesRecord: "or".} = ref object
-    `data`*: DefinitionOrData
+    `field0`*: DefinitionOrField0
 
-  DefinitionAndData* {.preservesTuple.} = ref object
+  DefinitionAndField0* {.preservesTuple.} = ref object
     `pattern0`*: NamedPattern
     `pattern1`*: NamedPattern
     `patternN`* {.preservesTupleTail.}: seq[NamedPattern]
 
   DefinitionAnd* {.preservesRecord: "and".} = ref object
-    `data`*: DefinitionAndData
+    `field0`*: DefinitionAndField0
 
   `Definition`* {.preservesOr.} = ref object
     case orKind*: DefinitionKind
@@ -162,13 +162,13 @@ type
     `variantLabel`*: string
     `pattern`*: Pattern
 
-  SchemaData* {.preservesDictionary.} = ref object
-    `version`* {.preservesLiteral: "1".}: bool
+  SchemaField0* {.preservesDictionary.} = ref object
+    `version`* {.preservesLiteral: "1".}: tuple[]
     `embeddedType`*: EmbeddedTypeName
     `definitions`*: Definitions
 
   Schema* {.preservesRecord: "schema".} = ref object
-    `data`*: SchemaData
+    `field0`*: SchemaField0
 
   PatternKind* {.pure.} = enum
     `SimplePattern`, `CompoundPattern`
diff --git a/src/preserves/schemaparse.nim b/src/preserves/schemaparse.nim
index 52fc2fa..6f1d00c 100644
--- a/src/preserves/schemaparse.nim
+++ b/src/preserves/schemaparse.nim
@@ -12,7 +12,7 @@ type
   Value = Preserve[void]
   Stack = seq[tuple[node: Value, pos: int]]
   ParseState = object
-    schema: SchemaData
+    schema: SchemaField0
     stack: Stack
     directory: string
 
@@ -289,9 +289,9 @@ proc parsePreservesSchema*(text: string; directory = getCurrentDir()): Schema =
   ## Schemas in binary encoding should instead be parsed as Preserves
   ## and converted to `Schema` with `fromPreserve` or `preserveTo`.
   assert directory != ""
-  var p = ParseState(schema: SchemaData(), directory: directory)
+  var p = ParseState(schema: SchemaField0(), directory: directory)
   match(text, p)
-  Schema(data: p.schema)
+  Schema(field0: p.schema)
 
 when isMainModule:
   import std/streams