[project @ 2003-07-24 12:19:57 by ralf]

[ghc-base.git] / include / Typeable.h

diff --git a/include/Typeable.h b/include/Typeable.h
new file mode 100644 (file)
index 0000000..5486e1e
--- /dev/null
+++ b/include/Typeable.h
@@ -0,0 +1,25 @@
+/* ----------------------------------------------------------------------------
+ * Macros to help make Typeable instances.
+ * -------------------------------------------------------------------------- */
+
+#define INSTANCE_TYPEABLE0(tycon,tcname,str) \
+tcname = mkTyCon str; \
+instance Typeable tycon where { typeOf _ = mkAppTy tcname [] }
+
+#define INSTANCE_TYPEABLE1(tycon,tcname,str) \
+tcname = mkTyCon str; \
+instance Typeable a => Typeable (tycon a) where { \
+  typeOf x = mkAppTy tcname [typeOf ((undefined :: tycon a -> a) x) ] }
+
+#define INSTANCE_TYPEABLE2(tycon,tcname,str) \
+tcname = mkTyCon str; \
+instance (Typeable a, Typeable b) => Typeable (tycon a b) where { \
+  typeOf x = mkAppTy tcname [typeOf ((undefined :: tycon a b -> a) x), \
+                            typeOf ((undefined :: tycon a b -> b) x)] }
+
+#define INSTANCE_TYPEABLE3(tycon,tcname,str) \
+tcname = mkTyCon str; \
+instance (Typeable a, Typeable b, Typeable c) => Typeable (tycon a b c) where {\
+  typeOf a = mkAppTy tcname [typeOf ((undefined :: tycon a b c -> a) a), \
+                            typeOf ((undefined :: tycon a b c -> b) a), \
+                            typeOf ((undefined :: tycon a b c -> c) a)] }