From effc285ff0be62636148d66bb4bf0002baaf14e8 Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Wed, 18 Jan 2006 10:49:32 +0000
Subject: [PATCH] [project @ 2006-01-18 10:49:32 by simonmar] Implement :main
 (see ticket #662)

Patch from Volker Stolz, minor mods by me

When matching commands, we now look for (a) an exact match, and (b)
the first prefix match we find in the list.  This is so that :module
can still be abbreviated by :m, to avoid surprise.

Docs still to do.
---
 ghc/compiler/ghci/InteractiveUI.hs |   23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/ghc/compiler/ghci/InteractiveUI.hs b/ghc/compiler/ghci/InteractiveUI.hs
index 112e672..dd4343f 100644
--- a/ghc/compiler/ghci/InteractiveUI.hs
+++ b/ghc/compiler/ghci/InteractiveUI.hs
@@ -104,6 +104,7 @@ builtin_commands = [
   ("info",      keepGoing info),
   ("load",	keepGoingPaths loadModule_),
   ("module",	keepGoing setContext),
+  ("main",	keepGoing runMain),
   ("reload",	keepGoing reloadModule),
   ("check",	keepGoing checkModule),
   ("set",	keepGoing setCmd),
@@ -138,6 +139,7 @@ helpText =
  "   :info [<name> ...]          display information about the given names\n" ++
  "   :load <filename> ...        load module(s) and their dependents\n" ++
  "   :module [+/-] [*]<mod> ...  set the context for expression evaluation\n" ++
+ "   :main [<arguments> ...]     run the main function with the given arguments\n" ++
  "   :reload                     reload the current module set\n" ++
  "\n" ++
  "   :set <option> ...           set options\n" ++
@@ -487,14 +489,13 @@ specialCommand ('!':str) = shellEscape (dropWhile isSpace str)
 specialCommand str = do
   let (cmd,rest) = break isSpace str
   cmds <- io (readIORef commands)
-  case [ (s,f) | (s,f) <- cmds, prefixMatch cmd s ] of
-     []      -> io (hPutStr stdout ("unknown command ':" ++ cmd ++ "'\n" 
+  -- look for exact match first, then the first prefix match
+  case [ (s,f) | (s,f) <- cmds, cmd == s ] of
+     (_,f):_ -> f (dropWhile isSpace rest)
+     [] -> case [ (s,f) | (s,f) <- cmds, prefixMatch cmd s ] of
+     		[] -> io (hPutStr stdout ("unknown command ':" ++ cmd ++ "'\n" 
 		                    ++ shortHelpText) >> return False)
-     [(_,f)] -> f (dropWhile isSpace rest)
-     cs      -> io (hPutStrLn stdout ("prefix " ++ cmd ++ 
-			    	      " matches multiple commands (" ++ 
-	         	     	       foldr1 (\a b -> a ++ ',':b) (map fst cs)
-					 ++ ")") >> return False)
+     		(_,f):_ -> f (dropWhile isSpace rest)
 
 -----------------------------------------------------------------------------
 -- To flush buffers for the *interpreted* computation we need
@@ -579,6 +580,12 @@ pprInfo exts (thing, fixity, insts)
 -----------------------------------------------------------------------------
 -- Commands
 
+runMain :: String -> GHCi ()
+runMain args = do
+  let ss = concat $ intersperse "," (map (\ s -> ('"':s)++"\"") (toArgs args))
+  runCommand $ '[': ss ++ "] `System.Environment.withArgs` main"
+  return ()
+
 addModule :: [FilePath] -> GHCi ()
 addModule files = do
   io (revertCAFs)			-- always revert CAFs on load/add.
@@ -624,7 +631,7 @@ defineMacro s = do
   case maybe_hv of
      Nothing -> return ()
      Just hv -> io (writeIORef commands --
-		    ((macro_name, keepGoing (runMacro hv)) : cmds))
+		    (cmds ++ [(macro_name, keepGoing (runMacro hv))]))
 
 runMacro :: GHC.HValue{-String -> IO String-} -> String -> GHCi ()
 runMacro fun s = do
-- 
1.7.10.4