2 files changed, 11 insertions, 1 deletions
diff --git a/src/Language/GraphQL/AST/Parser.hs b/src/Language/GraphQL/AST/Parser.hs
index 274045d..41748b2 100644
--- a/src/Language/GraphQL/AST/Parser.hs
+++ b/src/Language/GraphQL/AST/Parser.hs
@@ -38,6 +38,7 @@ typeSystemDefinition = schemaDefinition
 typeDefinition :: Parser TypeDefinition
 typeDefinition = scalarTypeDefinition
     <|> objectTypeDefinition
+    <|> interfaceTypeDefinition
     <|> unionTypeDefinition
     <?> "TypeDefinition"
 
@@ -83,6 +84,15 @@ unionMemberTypes sepBy' = UnionMemberTypes
     <*> name `sepBy'` pipe
     <?> "UnionMemberTypes"
 
+interfaceTypeDefinition :: Parser TypeDefinition
+interfaceTypeDefinition = InterfaceTypeDefinition
+    <$> description
+    <* symbol "interface"
+    <*> name
+    <*> opt directives
+    <*> braces (many fieldDefinition)
+    <?> "InterfaceTypeDefinition"
+
 implementsInterfaces ::
     Foldable t =>
     (Parser Text -> Parser Text -> Parser (t NamedType)) ->
diff --git a/src/Language/GraphQL/Schema.hs b/src/Language/GraphQL/Schema.hs
index 8bdf605..661e452 100644
--- a/src/Language/GraphQL/Schema.hs
+++ b/src/Language/GraphQL/Schema.hs
@@ -94,7 +94,7 @@ resolveFieldValue f resolveRight fld@(Field _ _ args _) = do
             _ <- addErrMsg err
             return $ HashMap.singleton (aliasOrName fld) Aeson.Null
 
--- | Helper function to facilitate 'Argument' handling.
+-- | Helper function to facilitate error handling and result emitting.
 withField :: (MonadIO m, Aeson.ToJSON a)
     => CollectErrsT m a -> Field -> CollectErrsT m (HashMap Text Aeson.Value)
 withField v fld