[project @ 2003-02-19 15:54:05 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcSplice.lhs

diff --git a/ghc/compiler/typecheck/TcSplice.lhs b/ghc/compiler/typecheck/TcSplice.lhs
index b893dcc..d191fcd 100644 (file)
--- a/ghc/compiler/typecheck/TcSplice.lhs
+++ b/ghc/compiler/typecheck/TcSplice.lhs
@@ -25,7 +25,7 @@ import TcExpr         ( tcMonoExpr )
 import TcHsSyn         ( TcExpr, TypecheckedHsExpr, mkHsLet, zonkTopExpr )
 import TcSimplify      ( tcSimplifyTop )
 import TcType          ( TcType, openTypeKind, mkAppTy )
-import TcEnv           ( spliceOK, tcMetaTy )
+import TcEnv           ( spliceOK, tcMetaTy, tcWithTempInstEnv )
 import TcRnTypes       ( TopEnv(..) )
 import TcMType         ( newTyVarTy, zapToType )
 import Name            ( Name )
@@ -63,20 +63,49 @@ tcSpliceDecls e     = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e)
 
 %************************************************************************
 %*                                                                     *
-\subsection{Splicing an expression}
+\subsection{Quoting an expression}
 %*                                                                     *
 %************************************************************************
 
 \begin{code}
 tcBracket :: HsBracket Name -> TcM TcType
-tcBracket (ExpBr expr) 
+tcBracket brack
+  = getStage                           `thenM` \ level ->
+    case bracketOK level of {
+       Nothing         -> failWithTc (illegalBracket level) ;
+       Just next_level ->
+
+       -- Typecheck expr to make sure it is valid,
+       -- but throw away the results.  We'll type check
+       -- it again when we actually use it.
+    newMutVar []                       `thenM` \ pending_splices ->
+    getLIEVar                          `thenM` \ lie_var ->
+
+    setStage (Brack next_level pending_splices lie_var) (
+       getLIE (tc_bracket brack)
+    )                                  `thenM` \ (meta_ty, lie) ->
+    tcSimplifyBracket lie              `thenM_`  
+
+    unifyTauTy res_ty meta_ty          `thenM_`
+
+       -- Return the original expression, not the type-decorated one
+    readMutVar pending_splices         `thenM` \ pendings ->
+    returnM (HsBracketOut brack pendings)
+    }
+
+tc_bracket (ExpBr expr) 
   = newTyVarTy openTypeKind            `thenM` \ any_ty ->
     tcMonoExpr expr any_ty             `thenM_`
     tcMetaTy exprTyConName
        -- Result type is Expr (= Q Exp)
 
-tcBracket (DecBr decls)
-  = tcTopSrcDecls decls                        `thenM_`
+tc_bracket (DecBr decls)
+  = tcWithTempInstEnv (tcTopSrcDecls decls)    `thenM_`
+       -- Typecheck the declarations, dicarding any side effects
+       -- on the instance environment (which is in a mutable variable)
+       -- and the extended environment.  We'll get all that stuff
+       -- later, when we splice it in
+
     tcMetaTy decTyConName              `thenM` \ decl_ty ->
     tcMetaTy qTyConName                        `thenM` \ q_ty ->
     returnM (mkAppTy q_ty (mkListTy decl_ty))
@@ -364,6 +393,9 @@ showSplice what before after
                                    text "======>",
                                    nest 2 after])])
 
+illegalBracket level
+  = ptext SLIT("Illegal bracket at level") <+> ppr level
+
 illegalSplice level
   = ptext SLIT("Illegal splice at level") <+> ppr level