all: added primitives

src/BC/Primitives.hs

@@ -0,0 +1,26 @@
+module BC.Primitives where
+
+import BC.Types
+
+primitives :: [(String, Value)]
+primitives = map valuize primitivesList
+  where valuize (x, y) = (x, BNative y)
+
+
+primitivesList :: [(String, [Value] -> Value)]
+primitivesList = [ ("cos", pcos)
+                 , ("sqrt", psqrt)
+                 ]
+
+
+psqrt :: [Value] -> Value
+psqrt [BNum (BInt x)] = BNum $ BFloat $ sqrt $ fromIntegral x
+psqrt [BNum (BFloat x)] = BNum $ BFloat $ sqrt x
+psqrt [x] = BErr $ "Expected argument to be a number, got " ++ show x
+
+
+pcos :: [Value] -> Value
+pcos [BNum (BInt x)] = BNum $ BFloat $ cos $ fromIntegral x
+pcos [BNum (BFloat x)] = BNum $ BFloat $ cos x
+pcos [x] = BErr $ "Expected argument to be a number, got " ++ show x
+