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

diff --git a/compiler/typecheck/TcSplice.lhs b/compiler/typecheck/TcSplice.lhs
index a99bf8b..e23155d 100644 (file)
--- a/compiler/typecheck/TcSplice.lhs
+++ b/compiler/typecheck/TcSplice.lhs
@@ -91,6 +91,18 @@ tcSpliceDecls e     = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e)
 %*                                                                     *
 %************************************************************************
 
+Note [Handling brackets]
+~~~~~~~~~~~~~~~~~~~~~~~~
+Source:                f = [| Just $(g 3) |]
+  The [| |] part is a HsBracket
+
+Typechecked:   f = [| Just ${s7}(g 3) |]{s7 = g Int 3}
+  The [| |] part is a HsBracketOut, containing *renamed* (not typechecked) expression
+  The "s7" is the "splice point"; the (g Int 3) part is a typechecked expression
+
+Desugared:     f = do { s7 <- g Int 3
+                      ; return (ConE "Data.Maybe.Just" s7) }
+
 \begin{code}
 tcBracket :: HsBracket Name -> BoxyRhoType -> TcM (LHsExpr TcId)
 tcBracket brack res_ty