1 files changed, 16 insertions, 2 deletions
diff --git a/Data/GraphQL.hs b/Data/GraphQL.hs
index 2da8a46..dfe9362 100644
--- a/Data/GraphQL.hs
+++ b/Data/GraphQL.hs
@@ -1,6 +1,7 @@
+-- | This module provides the functions to parse and execute @GraphQL@ queries.
 module Data.GraphQL where
 
-import Control.Applicative (Alternative, empty)
+import Control.Applicative (Alternative)
 
 import Data.Text (Text)
 
@@ -11,10 +12,23 @@ import Data.GraphQL.Execute
 import Data.GraphQL.Parser
 import Data.GraphQL.Schema
 
+import Data.GraphQL.Error
+
+-- | Takes a 'Schema' and text representing a @GraphQL@ request document.
+--   If the text parses correctly as a @GraphQL@ query the query is
+--   executed according to the given 'Schema'.
+--
+--   Returns the response as an @Aeson.@'Aeson.Value'.
 graphql :: (Alternative m, Monad m) => Schema m -> Text -> m Aeson.Value
 graphql = flip graphqlSubs $ const Nothing
 
+-- | Takes a 'Schema', a variable substitution function and text
+--   representing a @GraphQL@ request document.  If the text parses
+--   correctly as a @GraphQL@ query the substitution is applied to the
+--   query and the query is then executed according to the given 'Schema'.
+--
+--   Returns the response as an @Aeson.@'Aeson.Value'.
 graphqlSubs :: (Alternative m, Monad m) => Schema m -> Subs -> Text -> m Aeson.Value
 graphqlSubs schema f =
-    either (const empty) (execute schema f)
+    either parseError (execute schema f)
   . Attoparsec.parseOnly document