Collect imports from schema

src/preserves/private/preserves_schema_nim.nim

@@ -372,6 +372,22 @@ proc generateProcs(result: var seq[PNode]; name: string; sn: SchemaNode) =
         initRecordCall))
   else: discard
 
+proc collectRefImports(imports: PNode; sn: SchemaNode) =
+  case sn.kind
+  of snkRef:
+    if sn.refPath.len > 1:
+      imports.add ident(sn.refPath[0])
+  else:
+    for child in sn.items:
+      collectRefImports(imports, child)
+
+proc collectRefImports(imports: PNode; scm: Schema) =
+  if scm.embeddedType.contains {'.'}:
+    let m = split(scm.embeddedType, '.', 1 )[0]
+    imports.add ident(m)
+  for _, def in scm.definitions:
+    collectRefImports(imports, def)
+
 proc generateNimFile*(scm: Schema; path: string) =
   var
     knownTypes: TypeTable
@@ -441,11 +457,11 @@ proc generateNimFile*(scm: Schema; path: string) =
       generateProcs(procs, name, def)
   for typeDef in knownTypes.values:
     typeSection.add typeDef
-  var
-    imports = nkImportStmt.newNode.add(
-      ident"std/typetraits",
-      ident"preserves")
-    module = newNode(nkStmtList).add(
+  var imports = nkImportStmt.newNode.add(
+    ident"std/typetraits",
+    ident"preserves")
+  collectRefImports(imports, scm)
+  var module = newNode(nkStmtList).add(
       imports,
       typeSection,
       constSection

src/preserves/schemas.nim

@@ -75,6 +75,19 @@ proc add(a: SchemaNode; b: SchemaNode|seq[SchemaNode]): SchemaNode {.discardable
   a.nodes.add b
   a
 
+iterator items*(sn: SchemaNode): SchemaNode =
+  case sn.kind
+  of snkAny, snkAtom, snkLiteral, snkRef: discard
+  of snkAlt:
+    yield sn.altBranch
+  of snkEmbedded:
+    yield sn.embed
+  of snkNamed:
+    yield sn.pattern
+  else:
+    for i in 0..sn.nodes.high:
+      yield sn.nodes[i]
+
 proc `$`*(n: SchemaNode): string =
   case n.kind
   of snkOr: