Use a better project structure

1 files changed, 23 insertions, 0 deletions

diff --git a/server/src/Validation.hs b/server/src/Validation.hs
new file mode 100644
index 0000000..1f332c9
--- /dev/null
+++ b/server/src/Validation.hs
@@ -0,0 +1,23 @@
+module Validation
+  ( nonEmpty
+  , number
+  ) where
+
+import Data.Text (Text)
+import qualified Data.Text as T
+
+nonEmpty :: Text -> Maybe Text
+nonEmpty str =
+  if T.null str
+   then Nothing
+   else Just str
+
+number :: (Int -> Bool) -> Text -> Maybe Int
+number numberForm str =
+  case reads (T.unpack str) :: [(Int, String)] of
+    (num, _) : _ ->
+      if numberForm num
+        then Just num
+        else Nothing
+    _ ->
+      Nothing