[project @ 2004-09-30 10:35:15 by simonpj]

------------------------------------
	Add Generalised Algebraic Data Types
	------------------------------------

This rather big commit adds support for GADTs.  For example,

    data Term a where
 	  Lit :: Int -> Term Int
	  App :: Term (a->b) -> Term a -> Term b
	  If  :: Term Bool -> Term a -> Term a
	  ..etc..

    eval :: Term a -> a
    eval (Lit i) = i
    eval (App a b) = eval a (eval b)
    eval (If p q r) | eval p    = eval q
    		    | otherwise = eval r


Lots and lots of of related changes throughout the compiler to make
this fit nicely.

One important change, only loosely related to GADTs, is that skolem
constants in the typechecker are genuinely immutable and constant, so
we often get better error messages from the type checker.  See
TcType.TcTyVarDetails.

There's a new module types/Unify.lhs, which has purely-functional
unification and matching for Type. This is used both in the typechecker
(for type refinement of GADTs) and in Core Lint (also for type refinement).

1 files changed, 3 insertions, 10 deletions

diff --git a/ghc/compiler/HsVersions.h b/ghc/compiler/HsVersions.h
index 0bd9c142c4..8852fd8adc 100644
--- a/ghc/compiler/HsVersions.h
+++ b/ghc/compiler/HsVersions.h
@@ -64,23 +64,16 @@ name = Util.global (value) :: IORef (ty); \
 #define ASSERT(e) if (not (e)) then (assertPanic __FILE__ __LINE__) else
 #define ASSERT2(e,msg) if (not (e)) then (assertPprPanic __FILE__ __LINE__ (msg)) else
 #define WARN( e, msg ) (warnPprTrace (e) __FILE__ __LINE__ (msg))
-#define ASSERTM(e) ASSERT(e) do
+#define ASSERTM(mbool) do { bool <- mbool; ASSERT(bool) return () }
+#define ASSERTM2(mbool,msg) do { bool <- mbool; ASSERT2(bool,msg) return () }
 #else
 #define ASSERT(e)      if False then error "ASSERT"  else
 #define ASSERT2(e,msg) if False then error "ASSERT2" else
 #define ASSERTM(e)
+#define ASSERTM2(e)
 #define WARN(e,msg)    if False then error "WARN"    else
 #endif
 
--- temporary usage assertion control KSW 2000-10
-#ifdef DO_USAGES
-#define UASSERT(e) ASSERT(e)
-#define UASSERT2(e,msg) ASSERT2(e,msg)
-#else
-#define UASSERT(e)
-#define UASSERT2(e,msg)
-#endif
-
 -- This #ifndef lets us switch off the "import FastString"
 -- when compiling FastString itself
 #ifndef COMPILING_FAST_STRING