From 27e11b20b06f2f2dbfb56c0998a63169b4b8abc4 Mon Sep 17 00:00:00 2001
From: Joris
Date: Wed, 8 Nov 2017 23:47:26 +0100
Subject: Use a better project structure

---
 server/src/Validation.hs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 server/src/Validation.hs

(limited to 'server/src/Validation.hs')

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
-- 
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