Added Unlambda interpreter, currently without support for C,E,@,|,?

1 files changed, 68 insertions, 0 deletions

diff --git a/Unlambda/Interpreter.hs b/Unlambda/Interpreter.hs
new file mode 100644
index 0000000..170b2a7
--- /dev/null
+++ b/Unlambda/Interpreter.hs
@@ -0,0 +1,68 @@
+module Unlambda.Interpreter (
+    unlambda
+    ) where
+
+
+import Unlambda.Parser
+
+
+
+
+unlambda :: UnlambdaTerm -> IO UnlambdaTerm
+unlambda term = eval term
+
+
+
+eval :: UnlambdaTerm -> IO UnlambdaTerm
+eval term =
+    case term of
+        App f x -> do
+            t <- eval f
+            apply t x
+        _ -> return term
+
+
+
+apply :: UnlambdaTerm -> UnlambdaTerm -> IO UnlambdaTerm
+apply firstTerm secondTerm =
+    case firstTerm of
+        K -> eval secondTerm >>= return . Kpartial
+
+        Kpartial x -> eval secondTerm >> return x
+
+        S -> eval secondTerm >>= return . Spartial
+
+        Spartial x -> eval secondTerm >>= return . (Sapp x)
+
+        Sapp x y -> do
+            z <- eval secondTerm
+            result <- eval (App (App x z) (App y z))
+            return result
+
+        I -> eval secondTerm
+
+        V -> eval secondTerm >> return V
+
+        C -> return I --placeholder
+
+        D -> return (Promise secondTerm)
+
+        Promise x -> do
+            y <- eval secondTerm
+            result <- eval (App x y)
+            return result
+
+        Dot c -> putChar c >> eval secondTerm
+
+        R -> putChar '\n' >> eval secondTerm
+
+        E -> return I --placeholder
+
+        Reed -> return I --placeholder
+
+        Bar -> return I --placeholder
+
+        Compare c -> return I --placeholder
+
+        Continuation cont -> return I --placeholder
+