Make builtinAdd2 polymorphic in numeric types

2 files changed, 17 insertions, 5 deletions

diff --git a/src/Builtins.hs b/src/Builtins.hs
index dc6b44c..1ac532a 100644
--- a/src/Builtins.hs
+++ b/src/Builtins.hs
@@ -16,14 +16,25 @@ builtinEnv = M.fromList [
     ("prepend", builtinPrepend)
     ]
 
+-- maybe make a builtinBinaryFunction?
+-- builtinAdd2 = builtinBinaryFunction (ASTInteger a) (ASTInteger b) (\a b -> a + b)
 builtinAdd2 :: AST
 builtinAdd2 =
-    let outer _ ast1 = do
-            (ASTInteger a) <- assertIsASTInteger ast1
-            let inner _ ast2 = do
-                    (ASTInteger b) <- assertIsASTInteger ast2
+    let outer :: LFunction
+        outer _ (ASTInteger a) = do
+            let inner :: LFunction
+                inner _ (ASTInteger b) =
                     return $ ASTInteger $ a + b
+                inner _ other = throwError $ LException $ "invalid argument to integer add: " ++ show other
+            return $ ASTFunction $ inner
+        outer _ (ASTDouble a) = do
+            let inner :: LFunction
+                inner _ (ASTDouble b) =
+                    return $ ASTDouble $ a + b
+                inner _ other = throwError $ LException $ "invalid argument to double add: " ++ show other
             return $ ASTFunction $ inner
+        outer _ other = throwError $ LException $ "non-numeric argument to add: " ++ show other
+
      in ASTFunction outer
 
 builtinSubtract2 :: AST
diff --git a/src/Types.hs b/src/Types.hs
index 08736cc..21a1ceb 100644
--- a/src/Types.hs
+++ b/src/Types.hs
@@ -5,6 +5,7 @@ import Control.Monad.Except
 import Control.Monad.Reader
 import qualified Data.Map as M
 import qualified Data.List as L
+import qualified Data.Char as C
 import Utils
 
 newtype LException = LException String
@@ -36,7 +37,7 @@ instance (Show AST) where
     show (ASTInteger n) = show n
     show (ASTDouble n) = show n
     show (ASTSymbol s) = s
-    show (ASTBoolean b) = show b
+    show (ASTBoolean b) = show b $> map C.toLower
     show (ASTString s) = show s
     show (ASTVector v) = "[" ++ L.intercalate " " (map show v) ++ "]"
     show (ASTFunctionCall v) = "(" ++ L.intercalate " " (map show v) ++ ")"