Add documentation examples

automaton/automaton.cabal

@@ -104,6 +104,20 @@ test-suite automaton-test
     tasty-hunit ^>=0.10,
     tasty-quickcheck >=0.10 && <0.12,
 
+executable UserSawtooth
+  import: opts
+  hs-source-dirs: examples
+  main-is: UserSawtooth.hs
+  build-depends:
+    automaton
+
+executable ForeverSawtooth
+  import: opts
+  hs-source-dirs: examples
+  main-is: ForeverSawtooth.hs
+  build-depends:
+    automaton
+
 flag dev
   description: Enable warnings as errors. Active on ci.
   default: False

automaton/examples/ForeverSawtooth.hs

@@ -0,0 +1,13 @@
+-- base
+import Control.Arrow ((>>>))
+import Control.Monad (guard)
+
+-- automaton
+import Data.Automaton
+import Data.Automaton.Trans.Except
+
+sawtooth :: Automaton IO a Int
+sawtooth = forever $ try $ count >>> throwOnMaybe (\n -> guard (n > 10))
+
+main :: IO ()
+main = reactimate $ sawtooth >>> arrM print

automaton/examples/UserSawtooth.hs

@@ -0,0 +1,18 @@
+-- base
+import Control.Arrow ((>>>))
+import Control.Monad (guard)
+
+-- automaton
+import Data.Automaton
+import Data.Automaton.Trans.Except
+
+userSawtooth :: Int -> Automaton IO a Int
+userSawtooth nMax = safely $ do
+  try $ count >>> throwOnMaybe (\n -> guard (n > nMax))
+  nMax' <- once_ $ do
+    putStrLn "Maximum reached, please enter next nMax:"
+    readLn
+  safe $ userSawtooth nMax'
+
+main :: IO ()
+main = reactimate $ userSawtooth 10 >>> arrM print