Write a calculator

It's pretty nice. It works for what I want. I don't think I have any
complaints about its functionality. I'll add new functions as I need
them. Haskell is actually really easy to program in. I wonder actually
if this would have been easier in Python. I think no.

1 files changed, 34 insertions, 0 deletions

diff --git a/main.hs b/main.hs
new file mode 100644
index 0000000..3c3d457
--- /dev/null
+++ b/main.hs
@@ -0,0 +1,34 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+import Graphics.UI.Gtk
+import qualified Control.Monad.IO.Class as Cl
+import qualified RealCalc
+
+main :: IO ()
+main = do _ <- initGUI
+          w <- windowNew
+          windowSetKeepAbove w True
+          set w [ windowDecorated := False, windowTypeHint := WindowTypeHintDock, windowResizable := False ]
+          grid <- gridNew
+          input <- entryNew
+          output <- labelNew (Nothing :: Maybe String)
+          gridAttach grid input 0 0 1 1
+          gridAttach grid output 0 1 1 1
+          containerAdd w grid
+          _ <- w `on` deleteEvent $ do
+            Cl.liftIO mainQuit
+            return False
+          _ <- input `on` keyReleaseEvent $ do
+            k <- eventKeyName
+            let quit = Cl.liftIO mainQuit
+            case k of
+              "Escape" -> quit
+              "Return" -> quit
+              _ -> return ()
+            s <- Cl.liftIO $ entryGetText input
+            case RealCalc.calculate s of
+              Nothing -> return ()
+              Just r -> Cl.liftIO $ labelSetText output r
+            return False
+          widgetShowAll w
+          mainGUI