Ticket #2986: ghci-info-no-instances.patch

compiler/ghci/InteractiveUI.hs

@@ -211 +211 @@
  "   :edit                       edit last module\n" ++
  "   :etags [<file>]             create tags file for Emacs (default: \"TAGS\")\n" ++
  "   :help, :?                   display this list of commands\n" ++
- "   :info [<name> ...]          display information about the given names\n" ++
+ "   :info [-][<name> ...]       display information about the given names\n" ++
  "   :kind <type>                show the kind of <type>\n" ++
  "   :load [*]<module> ...       load module(s) and their dependents\n" ++
  "   :main [<arguments> ...]     run the main function with the given arguments\n" ++
@@ -876 +876 @@
 help _ = io (putStr helpText)
 
 info :: String -> GHCi ()
-info "" = ghcError (CmdLineError "syntax: ':i <thing-you-want-info-about>'")
+info "" = ghcError (CmdLineError "syntax: ':i [-]<thing-you-want-info-about>'")
+info "-"= ghcError (CmdLineError "syntax: ':i [-]<thing-you-want-info-about>'")
 info s  = handleSourceError GHC.printExceptionAndWarnings $ do
-             { let names = words s
-             ; dflags <- getDynFlags
+             { dflags <- getDynFlags
              ; let pefas = dopt Opt_PrintExplicitForalls dflags
              ; mapM_ (infoThing pefas) names }
   where
+    (wantInstances, names) = case s of
+                                '-' : s'-> (False, words s')
+                                _       -> (True, words s)
     infoThing pefas str = do
         names     <- GHC.parseName str
         mb_stuffs <- mapM GHC.getInfo names
@@ -891 +894 @@
         liftIO $
           putStrLn (showSDocForUser unqual $
                      vcat (intersperse (text "") $
-                           map (pprInfo pefas) filtered))
+                           map (pprInfo pefas wantInstances) filtered))
 
   -- Filter out names whose parent is also there Good
   -- example is '[]', which is both a type and data
@@ -902 +905 @@
   where
     implicits = mkNameSet [getName t | x <- xs, t <- implicitTyThings (get_thing x)]
 
-pprInfo :: PrintExplicitForalls -> (TyThing, Fixity, [GHC.Instance]) -> SDoc
-pprInfo pefas (thing, fixity, insts)
+pprInfo :: PrintExplicitForalls -> Bool -> (TyThing, Fixity, [GHC.Instance]) -> SDoc
+pprInfo pefas wantInstances (thing, fixity, insts)
   =  pprTyThingInContextLoc pefas thing
   $$ show_fixity fixity
-  $$ vcat (map GHC.pprInstance insts)
+  $$ if wantInstances then vcat (map GHC.pprInstance insts) else empty
   where
     show_fixity fix 
         | fix == GHC.defaultFixity = empty