ch05: Copy needed files from the examples

1 files changed, 48 insertions, 0 deletions

diff --git a/ch05/SimpleJSON.hs b/ch05/SimpleJSON.hs
new file mode 100644
index 0000000..d692168
--- /dev/null
+++ b/ch05/SimpleJSON.hs
@@ -0,0 +1,48 @@
+{-- snippet module --}
+module SimpleJSON
+    (
+      JValue(..)
+    , getString
+    , getInt
+    , getDouble
+    , getBool
+    , getObject
+    , getArray
+    , isNull
+    ) where
+{-- /snippet module --}
+
+{-- snippet JValue --}
+data JValue = JString String
+            | JNumber Double
+            | JBool Bool
+            | JNull
+            | JObject [(String, JValue)]
+            | JArray [JValue]
+              deriving (Eq, Ord, Show)
+{-- /snippet JValue --}
+
+{-- snippet getString --}
+getString :: JValue -> Maybe String
+getString (JString s) = Just s
+getString _           = Nothing
+{-- /snippet getString --}
+
+{-- snippet getters --}
+getInt (JNumber n) = Just (truncate n)
+getInt _           = Nothing
+
+getDouble (JNumber n) = Just n
+getDouble _           = Nothing
+
+getBool (JBool b) = Just b
+getBool _         = Nothing
+
+getObject (JObject o) = Just o
+getObject _           = Nothing
+
+getArray (JArray a) = Just a
+getArray _          = Nothing
+
+isNull v            = v == JNull
+{-- /snippet getters --}