[commit: ghc] master: Allow 'default' declarations in GHCi (520d82b)

[Simon Marlow]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/520d82b6ea81b39fcea6b4c06e40b38b85745599

>---------------------------------------------------------------

commit 520d82b6ea81b39fcea6b4c06e40b38b85745599
Author: Patrick Palka <patrick at parcs.ath.cx>
Date:   Sun Jul 8 12:49:22 2012 -0400

    Allow 'default' declarations in GHCi

>---------------------------------------------------------------

 compiler/main/HscMain.hs          |    5 ++++-
 compiler/main/HscTypes.lhs        |    4 ++++
 compiler/typecheck/TcRnDriver.lhs |    1 +
 ghc/InteractiveUI.hs              |    2 +-
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/compiler/main/HscMain.hs b/compiler/main/HscMain.hs
index 0b03e83..215a654 100644
--- a/compiler/main/HscMain.hs
+++ b/compiler/main/HscMain.hs
@@ -1510,6 +1510,8 @@ hscDeclsWithLocation hsc_env0 str source linenumber =
     let finsts = tcg_fam_insts tc_gblenv
         insts  = tcg_insts     tc_gblenv
 
+    let defaults = tcg_default tc_gblenv
+
     {- Desugar it -}
     -- We use a basically null location for iNTERACTIVE
     let iNTERACTIVELoc = ModLocation{ ml_hs_file   = Nothing,
@@ -1561,7 +1563,8 @@ hscDeclsWithLocation hsc_env0 str source linenumber =
 
     let ictxt1 = extendInteractiveContext icontext tythings
         ictxt  = ictxt1 { ic_sys_vars  = sys_vars ++ ic_sys_vars ictxt1,
-                          ic_instances = (insts, finsts) }
+                          ic_instances = (insts, finsts),
+                          ic_default   = defaults }
 
     return (tythings, ictxt)
 
diff --git a/compiler/main/HscTypes.lhs b/compiler/main/HscTypes.lhs
index adaa9a3..343df00 100644
--- a/compiler/main/HscTypes.lhs
+++ b/compiler/main/HscTypes.lhs
@@ -943,6 +943,9 @@ data InteractiveContext
              -- ^ The function that is used for printing results
              -- of expressions in ghci and -e mode.
 
+         ic_default :: Maybe [Type],
+             -- ^ The current default types, set by a 'default' declaration
+
 #ifdef GHCI
           ic_resume :: [Resume],
              -- ^ The stack of breakpoint contexts
@@ -987,6 +990,7 @@ emptyInteractiveContext dflags
                          ic_fix_env    = emptyNameEnv,
                          -- System.IO.print by default
                          ic_int_print  = printName,
+                         ic_default    = Nothing,
 #ifdef GHCI
                          ic_resume     = [],
 #endif
diff --git a/compiler/typecheck/TcRnDriver.lhs b/compiler/typecheck/TcRnDriver.lhs
index e3ec10a..0d00fb6 100644
--- a/compiler/typecheck/TcRnDriver.lhs
+++ b/compiler/typecheck/TcRnDriver.lhs
@@ -1197,6 +1197,7 @@ setInteractiveContext hsc_env icxt thing_inside
              -- setting tcg_field_env is necessary to make RecordWildCards work
              -- (test: ghci049)
         , tcg_fix_env      = ic_fix_env icxt
+        , tcg_default      = ic_default icxt
         }) $
 
         tcExtendGhciEnv visible_tmp_ids $ -- Note [GHCi temporary Ids]
diff --git a/ghc/InteractiveUI.hs b/ghc/InteractiveUI.hs
index 0dbd8ce..fd5337d 100644
--- a/ghc/InteractiveUI.hs
+++ b/ghc/InteractiveUI.hs
@@ -794,7 +794,7 @@ enqueueCommands cmds = do
 -- rather than a stmt.
 declPrefixes :: [String]
 declPrefixes = ["class ","data ","newtype ","type ","instance ", "deriving ",
-                "foreign "]
+                "foreign ", "default ", "default("]
 
 -- | Entry point to execute some haskell code from user
 runStmt :: String -> SingleStep -> GHCi Bool