1. 20 Feb, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-02-20 18:33:50 by simonpj] · 56b5a8b8
      simonpj authored
      -------------------------------------
            Add Core Notes and the {-# CORE #-} pragma
      	-------------------------------------
      
      This is an idea of Hal Daume's. The key point is that Notes in Core
      are augmented thus:
      
        data Note
          = SCC CostCentre
          | ...
          | CoreNote String     -- NEW
      
      These notes can be injected via a Haskell-source pragma:
      
         f x = ({-# CORE "foo" #-} show) ({-# CORE "bar" #-} x)
      
      This wraps a (Note (CoreNote "foo")) around the 'show' variable,
      and a similar note around the argument to 'show'.
      
      These notes are basically ignored by GHC, but are emitted into
      External Core, where they may convey useful information.
      
      Exactly how code involving these notes is munged by the simplifier
      isn't very well defined.  We'll see how it pans out.  Meanwhile
      the impact on the rest of the compiler is minimal.
      56b5a8b8
  2. 06 Nov, 2002 1 commit
  3. 29 Oct, 2002 1 commit
  4. 23 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-23 14:30:00 by simonpj] · 203a687f
      simonpj authored
      ------------------------------------------------
      	Allow implicit-parameter bindings anywhere that
      		a normal binding group is allowed.
      	------------------------------------------------
      
      That is, you can have implicit parameters
      
      	* in a let binding
      	* in a where clause (but then you can't have non-implicit
      	  ones as well)
      	* in a let group in a list comprehension or monad do-notation
      
      The implementation is simple: just add IPBinds to the allowable forms of HsBinds,
      and remove the HsWith expression form altogether.   (It now comes in via the
      HsLet form.)
      
      It'a a nice generalisation really.  Needs a bit of documentation, which I'll do next.
      203a687f
  5. 18 Oct, 2002 1 commit
  6. 09 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-09 15:03:48 by simonpj] · 8c1b6bd7
      simonpj authored
      -----------------------------------
      	Lots more Template Haskell stuff
      	-----------------------------------
      
      At last!  Top-level declaration splices work!
      Syntax is
      
      	$(f x)
      
      not "splice (f x)" as in the paper.
      
      Lots jiggling around, particularly with the top-level plumbining.
      Note the new data type HsDecls.HsGroup.
      8c1b6bd7
  7. 27 Sep, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-09-27 08:20:43 by simonpj] · dbc254c3
      simonpj authored
      --------------------------------
              Implement recursive do-notation
      	--------------------------------
      
      This commit adds recursive do-notation, which Hugs has had for some time.
      
      	mdo { x <- foo y ;
      	      y <- baz x ;
      	      return (y,x) }
      
      turns into
      
      	do { (x,y) <- mfix (\~(x,y) -> do { x <- foo y;
      					    y <- baz x }) ;
      	     return (y,x) }
      
      This is all based on work by Levent Erkok and John Lanuchbury.
      
      The really tricky bit is in the renamer (RnExpr.rnMDoStmts) where
      we break things up into minimal segments.  The rest is easy, including
      the type checker.
      
      Levent laid the groundwork, and Simon finished it off. Needless to say,
      I couldn't resist tidying up other stuff, so there's no guaranteed I
      have not broken something.
      dbc254c3
  8. 26 Sep, 2002 1 commit
  9. 25 Sep, 2002 1 commit
  10. 17 Sep, 2002 1 commit
  11. 16 Sep, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-09-16 07:31:11 by simonpj] · deafae58
      simonpj authored
      --------------------------------
         Quantify over unbound type vars in RULE lhs's
      	--------------------------------
      
      -- We need to gather the type variables mentioned on the LHS so we can
      -- quantify over them.  Example:
      --   data T a = C
      --
      --   foo :: T a -> Int
      --   foo C = 1
      --
      --   {-# RULES "myrule"  foo C = 1 #-}
      --
      -- After type checking the LHS becomes (foo a (C a))
      -- and we do not want to zap the unbound tyvar 'a' to (), because
      -- that limits the applicability of the rule.  Instead, we
      -- want to quantify over it!
      
      This commit fixes the problem, discovered by Manuel.  It uses a
      free-variable finder for RULE lhs's (TcRule.ruleLhsTvs) which relies
      on the fact that the LHS of a rule can only take ver forms
      (c.f RnSource.validRuleLhs).
      deafae58
  12. 13 Sep, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-09-13 15:02:25 by simonpj] · 9af77fa4
      simonpj authored
      --------------------------------------
      	Make Template Haskell into the HEAD
      	--------------------------------------
      
      This massive commit transfers to the HEAD all the stuff that
      Simon and Tim have been doing on Template Haskell.  The
      meta-haskell-branch is no more!
      
      WARNING: make sure that you
      
        * Update your links if you are using link trees.
          Some modules have been added, some have gone away.
      
        * Do 'make clean' in all library trees.
          The interface file format has changed, and you can
          get strange panics (sadly) if GHC tries to read old interface files:
          e.g.  ghc-5.05: panic! (the `impossible' happened, GHC version 5.05):
      	  Binary.get(TyClDecl): ForeignType
      
        * You need to recompile the rts too; Linker.c has changed
      
      
      However the libraries are almost unaltered; just a tiny change in
      Base, and to the exports in Prelude.
      
      
      NOTE: so far as TH itself is concerned, expression splices work
      fine, but declaration splices are not complete.
      
      
      		---------------
      		The main change
      		---------------
      
      The main structural change: renaming and typechecking have to be
      interleaved, because we can't rename stuff after a declaration splice
      until after we've typechecked the stuff before (and the splice
      itself).
      
      * Combine the renamer and typecheker monads into one
      	(TcRnMonad, TcRnTypes)
        These two replace TcMonad and RnMonad
      
      * Give them a single 'driver' (TcRnDriver).  This driver
        replaces TcModule.lhs and Rename.lhs
      
      * The haskell-src library package has a module
      	Language/Haskell/THSyntax
        which defines the Haskell data type seen by the TH programmer.
      
      * New modules:
      	hsSyn/Convert.hs 	converts THSyntax -> HsSyn
      	deSugar/DsMeta.hs 	converts HsSyn -> THSyntax
      
      * New module typecheck/TcSplice type-checks Template Haskell splices.
      
      		-------------
      		Linking stuff
      		-------------
      
      * ByteCodeLink has been split into
      	ByteCodeLink	(which links)
      	ByteCodeAsm	(which assembles)
      
      * New module ghci/ObjLink is the object-code linker.
      
      * compMan/CmLink is removed entirely (was out of place)
        Ditto CmTypes (which was tiny)
      
      * Linker.c initialises the linker when it is first used (no need to call
        initLinker any more).  Template Haskell makes it harder to know when
        and whether to initialise the linker.
      
      
      	-------------------------------------
      	Gathering the LIE in the type checker
      	-------------------------------------
      
      * Instead of explicitly gathering constraints in the LIE
      	tcExpr :: RenamedExpr -> TcM (TypecheckedExpr, LIE)
        we now dump the constraints into a mutable varabiable carried
        by the monad, so we get
      	tcExpr :: RenamedExpr -> TcM TypecheckedExpr
      
        Much less clutter in the code, and more efficient too.
        (Originally suggested by Mark Shields.)
      
      
      		-----------------
      		Remove "SysNames"
      		-----------------
      
      Because the renamer and the type checker were entirely separate,
      we had to carry some rather tiresome implicit binders (or "SysNames")
      along inside some of the HsDecl data structures.  They were both
      tiresome and fragile.
      
      Now that the typechecker and renamer are more intimately coupled,
      we can eliminate SysNames (well, mostly... default methods still
      carry something similar).
      
      		-------------
      		Clean up HsPat
      		-------------
      
      One big clean up is this: instead of having two HsPat types (InPat and
      OutPat), they are now combined into one.  This is more consistent with
      the way that HsExpr etc is handled; there are some 'Out' constructors
      for the type checker output.
      
      So:
      	HsPat.InPat	--> HsPat.Pat
      	HsPat.OutPat	--> HsPat.Pat
      	No 'pat' type parameter in HsExpr, HsBinds, etc
      
      	Constructor patterns are nicer now: they use
      		HsPat.HsConDetails
      	for the three cases of constructor patterns:
      		prefix, infix, and record-bindings
      
      	The *same* data type HsConDetails is used in the type
      	declaration of the data type (HsDecls.TyData)
      
      Lots of associated clean-up operations here and there.  Less code.
      Everything is wonderful.
      9af77fa4
  13. 29 Apr, 2002 1 commit
    • simonmar's avatar
      [project @ 2002-04-29 14:03:38 by simonmar] · b085ee40
      simonmar authored
      FastString cleanup, stage 1.
      
      The FastString type is no longer a mixture of hashed strings and
      literal strings, it contains hashed strings only with O(1) comparison
      (except for UnicodeStr, but that will also go away in due course).  To
      create a literal instance of FastString, use FSLIT("..").
      
      By far the most common use of the old literal version of FastString
      was in the pattern
      
      	  ptext SLIT("...")
      
      this combination still works, although it doesn't go via FastString
      any more.  The next stage will be to remove the need to use this
      special combination at all, using a RULE.
      
      To convert a FastString into an SDoc, now use 'ftext' instead of
      'ptext'.
      
      I've also removed all the FAST_STRING related macros from HsVersions.h
      except for SLIT and FSLIT, just use the relevant functions from
      FastString instead.
      b085ee40
  14. 24 Apr, 2002 1 commit
  15. 05 Apr, 2002 1 commit
    • sof's avatar
      [project @ 2002-04-05 15:18:25 by sof] · acc784b5
      sof authored
      Cleaned up the way the External Core front-end was
      integrated with the rest of the compiler;
      guided by detailed and helpful feedback from Simon PJ.
      
      Input files ending in ".hcr" are now assumed to contain
      external core -- still working on getting the renamer
      to slurp in interface files (implicitly) referred to
      in the Core source.
      acc784b5
  16. 01 Apr, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-04-01 08:23:30 by simonpj] · 9003a18c
      simonpj authored
      ------------------------------------
      	Change the treatment of the stupid
      	   context on data constructors
      	-----------------------------------
      
      Data types can have a context:
      
      	data (Eq a, Ord b) => T a b = T1 a b | T2 a
      
      and that makes the constructors have a context too
      (notice that T2's context is "thinned"):
      
      	T1 :: (Eq a, Ord b) => a -> b -> T a b
      	T2 :: (Eq a) => a -> T a b
      
      Furthermore, this context pops up when pattern matching
      (though GHC hasn't implemented this, but it is in H98, and
      I've fixed GHC so that it now does):
      
      	f (T2 x) = x
      gets inferred type
      	f :: Eq a => T a b -> a
      
      I say the context is "stupid" because the dictionaries passed
      are immediately discarded -- they do nothing and have no benefit.
      It's a flaw in the language.
      
      Up to now I have put this stupid context into the type of
      the "wrapper" constructors functions, T1 and T2, but that turned
      out to be jolly inconvenient for generics, and record update, and
      other functions that build values of type T (because they don't
      have suitable dictionaries available).
      
      So now I've taken the stupid context out.  I simply deal with
      it separately in the type checker on occurrences of a constructor,
      either in an expression or in a pattern.
      
      To this end
      
      * Lots of changes in DataCon, MkId
      
      * New function Inst.tcInstDataCon to instantiate a data constructor
      
      
      
      I also took the opportunity to
      
      * Rename
      	dataConId --> dataConWorkId
        for consistency.
      
      * Tidied up MkId.rebuildConArgs quite a bit, and renamed it
      	mkReboxingAlt
      
      * Add function DataCon.dataConExistentialTyVars, with the obvious meaning
      9003a18c
  17. 29 Mar, 2002 1 commit
    • sof's avatar
      [project @ 2002-03-29 21:39:36 by sof] · 76293b14
      sof authored
      Front end for External Core.
      
      Initial go at implementing a Core front end
      (enabled via -fcore); work in progress (renamer
      is currently not willing to slurp in & resolve
      imports.)
      76293b14
  18. 13 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-13 15:19:17 by simonpj] · 711e4d7a
      simonpj authored
      ----------------------------------
      	Do the Right Thing for TyCons where we
      	can't see all their constructors.
      	----------------------------------
      
      Inside a TyCon, three things can happen
      
      1. GHC knows all the constructors, and has them to hand.
         (Nowadays, there may be zero constructors.)
      
      2. GHC knows all the constructors, but has declined to slurp
         them all in, to avoid sucking in more declarations than
         necessary.  All we remember is the number of constructors,
         so we can get the return convention right.
      
      3. GHC doesn't know anything. This happens *only* for decls
         coming from .hi-boot files, where the programmer declines to
         supply a representation.
      
      Until now, these three cases have been conflated together.  Matters
      are worse now that a TyCon really can have zero constructors.  In
      fact, by confusing (3) with (1) we can actually generate bogus code.
      
      With this commit, the dataCons field of a TyCon is of type:
      
      data DataConDetails datacon
        = DataCons [datacon]	-- Its data constructors, with fully polymorphic types
      			-- A type can have zero constructors
      
        | Unknown		-- We're importing this data type from an hi-boot file
      			-- and we don't know what its constructors are
      
        | HasCons Int		-- In a quest for compilation speed we have imported
      			-- only the number of constructors (to get return
      			-- conventions right) but not the constructors themselves
      
      This says exactly what is going on.  There are lots of consequential small
      changes.
      711e4d7a
  19. 06 Feb, 2002 1 commit
    • keithw's avatar
      [project @ 2002-02-06 12:12:25 by keithw] · 37a47dd0
      keithw authored
      Merging the following onto the HEAD:
      
      |   1.61.2.1  +2 -4      fptools/ghc/compiler/rename/RnHsSyn.lhs
      |   1.135.2.1 +10 -0     fptools/ghc/compiler/rename/RnSource.lhs
      
      Original comment (keithw):
      
      Remove derivings FVs from tyClDeclFVs, because they aren't needed by
      interface files.  Instead, we return these FVs from
      finishSourceTyClDecl.
      37a47dd0
  20. 05 Feb, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-02-05 15:42:04 by simonpj] · e6601808
      simonpj authored
      ```------
      		Main.main
      		---------
      
      A bunch of related fixes concerning 'main'
      
      * Arrange that 'main' doesn't need to be defined in module Main;
        it can be imported.
      
      * The typechecker now injects a binding
      	Main.$main = PrelTopHandler.runMain main
      
        So the runtime system now calls Main.$main, not PrelMain.main.
        With z-encoding, this look like
      		Main_zdmain_closure
      
      * The function
        	PrelTopHandler.runMain :: IO a -> IO ()
        wraps the programmer's 'main' in an exception-cacthing wrapper.
      
      * PrelMain.hs and Main.hi-boot are both removed from lib/std, along
        with multiple lines of special case handling in lib/std/Makefile.
        This is a worthwhile cleanup.
      
      * Since we now pick up whatever 'main' is in scope, the ranamer gets
        in on the act (RnRnv.checkMain).  There is a little more info to
        get from the renamer to the typechecker, so I've defined a new type
        Rename.RnResult (c.f. TcModule.TcResult)
      
      * With GHCi, it's now a warning, not an error, to omit the binding
        of main (RnEnv.checkMain)
      
      * It would be easy to add a flag "-main-is foo"; the place to use
        that information is in RnEnv.checkMain.
      ```
      
      ----
      
      On the way I made a new type,
      	type HscTypes.FixityEnv = NameEnv Fixity
      and used it in various places I'd tripped over
      e6601808
  21. 04 Feb, 2002 1 commit
    • chak's avatar
      [project @ 2002-02-04 03:40:31 by chak] · 0299e1a1
      chak authored
      Foreign import/export declarations now conform to FFI Addendum Version 1.0
      
      * The old form of foreign declarations is still supported, but generates
        deprecation warnings.
      
      * There are some rather exotic old-style declarations which have become
        invalid as they are interpreted differently under the new scheme and there
        is no (easy) way to determine which style the programmer had in mind (eg,
        importing a C function with the name `wrapper' where the external name is
        explicitly given will not work in some situations - depends on whether an
        `unsafe' was specified and similar things).
      
      * Some "new" old-style forms have been introduced to make parsing a little bit
        easier (ie, avoid shift/reduce conflicts between new-style and old-style
        grammar rules), but they are few, arcane, and don't really hurt (and I won't
        tell what they are, you need to find that out by yourself ;-)
      
      * The FFI Addendum doesn't specify whether a header file that is requested for
        inclusion by multiple foreign declarations should be included only once or
        multiple times.  GHC at the moment includes an header as often as it appears
        in a foreign declaration.  For properly written headers, it doesn't make a
        difference anyway...
      
      * Library object specifications are currently silently ignored.  The feature
        was mainly requested for external calls in .NET (ie, calls which invoke C
        routines when Haskell is compiled to ILX), but those don't seem to be
        supported yet.
      
      * Foreign label declarations are currently broken, but they were already
        broken before I started messing with the stuff.
      
      The code is moderately tested.  All modules in lib/std/ and hslibs/lang/
      (using old-style declarations) still compile fine and I have run a couple of
      tests on the different forms of new-style declarations.
      0299e1a1
  22. 20 Dec, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-12-20 11:19:05 by simonpj] · 91c750cb
      simonpj authored
      ---------------------------------------------
      	More type system extensions (for John Hughes)
      	---------------------------------------------
      
      1.  Added a brand-new extension that lets you derive ARBITRARY CLASSES
      for newtypes.  Thus
      
      	newtype Age = Age Int deriving( Eq, Ord, Shape, Ix )
      
      The idea is that the dictionary for the user-defined class Shape Age
      is *identical* to that for Shape Int, so there is really no deriving
      work to do.   This saves you writing the very tiresome instance decl:
      
      	instance Shape Age where
      	   shape_op1 (Age x) = shape_op1 x
      	   shape_op2 (Age x1) (Age x2) = shape_op2 x1 x2
      	   ...etc...
      
      It's more efficient, too, becuase the Shape Age dictionary really
      will be identical to the Shape Int dictionary.
      
      There's an exception for Read and Show, because the derived instance
      *isn't* the same.
      
      There is a complication where higher order stuff is involved.  Here is
      the example John gave:
      
         class StateMonad s m | m -> s where ...
      
         newtype Parser tok m a = Parser (State [tok] (Failure m) a)
      			  deriving( Monad, StateMonad )
      
      Then we want the derived instance decls to be
      
         instance Monad (State [tok] (Failure m)) => Monad (Parser tok m)
         instance StateMonad [tok] (State [tok] (Failure m))
      	 => StateMonad [tok] (Parser tok m)
      
      John is writing up manual entry for all of this, but this commit
      implements it.   I think.
      
      
      2.  Added -fallow-incoherent-instances, and documented it.  The idea
      is that sometimes GHC is over-protective about not committing to a
      particular instance, and the programmer may want to say "commit anyway".
      Here's the example:
      
          class Sat a where
            dict :: a
      
          data EqD a = EqD {eq :: a->a->Bool}
      
          instance Sat (EqD a) => Eq a where
            (==) = eq dict
      
          instance Sat (EqD Integer) where
            dict = EqD{eq=(==)}
      
          instance Eq a => Sat (EqD a) where
            dict = EqD{eq=(==)}
      
          class Collection c cxt | c -> cxt where
            empty :: Sat (cxt a) => c a
            single :: Sat (cxt a) => a -> c a
            union :: Sat (cxt a) => c a -> c a -> c a
            member :: Sat (cxt a) => a -> c a -> Bool
      
          instance Collection [] EqD where
            empty = []
            single x = [x]
            union = (++)
            member = elem
      
      It's an updated attempt to model "Restricted Data Types", if you
      remember my Haskell workshop paper. In the end, though, GHC rejects
      the program (even with fallow-overlapping-instances and
      fallow-undecideable-instances), because there's more than one way to
      construct the Eq instance needed by elem.
      
      Yet all the ways are equivalent! So GHC is being a bit over-protective
      of me, really: I know what I'm doing and I would LIKE it to pick an
      arbitrary one. Maybe a flag fallow-incoherent-instances would be a
      useful thing to add?
      91c750cb
  23. 11 Dec, 2001 1 commit
  24. 06 Dec, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-12-06 10:45:42 by simonpj] · 61fae1d3
      simonpj authored
      --------------------------
      	Fix the instance-decl wart
      	--------------------------
      
      This commit implements the (proposed) H98 rule for
      resolving the class-method name in an instance decl.
      
      	module M( C( op1, op2 ) ) where
      		-- NB: op3 not exported
      	  class C a where
      	    op1, op2, op3 :: a -> a
      
      
      	module N where
      	  import qualified M as P( C )
      	  import qualified M as Q hiding( op2 )
      
      	  instance P.C Int where
      	    op1 x = x
      	    -- op2, op3 both illegal here
      
      The point is that
        a) only methods that can be named are legal
           in the instance decl
      	(so op2, op3 are not legal)
        b) but it doesn't matter *how* they can be named
      	(in this case Q.op1 is in scope, though
      	the class is called P.C)
      
      The AvailEnv carries the information about what's in scope,
      so we now have to carry it around in the monad, so that
      instance decl bindings can see it.  Quite simple really.
      
      Same deal for export lists. E.g.
      
      	module N( P.C( op1 ) ) where
      	  import qualified M as P( C )
      	  import qualified M as Q hiding( op2 )
      
      Actually this is what GHC has always implemented!
      61fae1d3
  25. 29 Nov, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-11-29 13:47:09 by simonpj] · 32a89583
      simonpj authored
      ------------------------------
      	Add linear implicit parameters
      	------------------------------
      
      Linear implicit parameters are an idea developed by Koen Claessen,
      Mark Shields, and Simon PJ, last week.  They address the long-standing
      problem that monads seem over-kill for certain sorts of problem, notably:
      
      	* distributing a supply of unique names
      	* distributing a suppply of random numbers
      	* distributing an oracle (as in QuickCheck)
      
      
      Linear implicit parameters are just like ordinary implicit parameters,
      except that they are "linear" -- that is, they cannot be copied, and
      must be explicitly "split" instead.  Linear implicit parameters are
      written '%x' instead of '?x'.  (The '/' in the '%' suggests the
      split!)
      
      For example:
      
          data NameSupply = ...
      
          splitNS :: NameSupply -> (NameSupply, NameSupply)
          newName :: NameSupply -> Name
      
          instance PrelSplit.Splittable NameSupply where
      	split = splitNS
      
      
          f :: (%ns :: NameSupply) => Env -> Expr -> Expr
          f env (Lam x e) = Lam x' (f env e)
      		    where
      		      x'   = newName %ns
      		      env' = extend env x x'
          ...more equations for f...
      
      Notice that the implicit parameter %ns is consumed
      	once by the call to newName
      	once by the recursive call to f
      
      So the translation done by the type checker makes
      the parameter explicit:
      
          f :: NameSupply -> Env -> Expr -> Expr
          f ns env (Lam x e) = Lam x' (f ns1 env e)
      		       where
      	 		 (ns1,ns2) = splitNS ns
      			 x' = newName ns2
      			 env = extend env x x'
      
      Notice the call to 'split' introduced by the type checker.
      How did it know to use 'splitNS'?  Because what it really did
      was to introduce a call to the overloaded function 'split',
      ndefined by
      
      	class Splittable a where
      	  split :: a -> (a,a)
      
      The instance for Splittable NameSupply tells GHC how to implement
      split for name supplies.  But we can simply write
      
      	g x = (x, %ns, %ns)
      
      and GHC will infer
      
      	g :: (Splittable a, %ns :: a) => b -> (b,a,a)
      
      The Splittable class is built into GHC.  It's defined in PrelSplit,
      and exported by GlaExts.
      
      Other points:
      
      * '?x' and '%x' are entirely distinct implicit parameters: you
        can use them together and they won't intefere with each other.
      
      * You can bind linear implicit parameters in 'with' clauses.
      
      * You cannot have implicit parameters (whether linear or not)
        in the context of a class or instance declaration.
      
      
      Warnings
      ~~~~~~~~
      The monomorphism restriction is even more important than usual.
      Consider the example above:
      
          f :: (%ns :: NameSupply) => Env -> Expr -> Expr
          f env (Lam x e) = Lam x' (f env e)
      		    where
      		      x'   = newName %ns
      		      env' = extend env x x'
      
      If we replaced the two occurrences of x' by (newName %ns), which is
      usually a harmless thing to do, we get:
      
          f :: (%ns :: NameSupply) => Env -> Expr -> Expr
          f env (Lam x e) = Lam (newName %ns) (f env e)
      		    where
      		      env' = extend env x (newName %ns)
      
      But now the name supply is consumed in *three* places
      (the two calls to newName,and the recursive call to f), so
      the result is utterly different.  Urk!  We don't even have
      the beta rule.
      
      Well, this is an experimental change.  With implicit
      parameters we have already lost beta reduction anyway, and
      (as John Launchbury puts it) we can't sensibly reason about
      Haskell programs without knowing their typing.
      
      Of course, none of this is throughly tested, either.
      32a89583
  26. 08 Nov, 2001 1 commit
    • sof's avatar
      [project @ 2001-11-08 19:20:55 by sof] · 56883a7f
      sof authored
      rnHsForeignDecl: 'foreign import's (incl 'f.e.d's) _define_ local toplevel
      names, so better use RnEnv.lookupTopBndrRn and not RnEnv.lookupOccRn to
      resolve the name.
      
      As was, declaring ForeignImports with the same name as an imported entity
      wasn't permitted.
      56883a7f
  27. 31 Oct, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-10-31 15:22:53 by simonpj] · 61bfd5dd
      simonpj authored
      ------------------------------------------
      	Improved handling of scoped type variables
      	------------------------------------------
      
      The main effect of this commit is to allow scoped type variables
      in pattern bindings, thus
      
      	(x::a, y::b) = e
      
      This was illegal, but now it's ok.  a and b have the same scope
      as x and y.
      
      
      On the way I beefed up the info inside a type variable
      (TcType.TyVarDetails; c.f. IdInfo.GlobalIdDetails) which
      helps to improve error messages. Hence the wide ranging changes.
      Pity about the extra loop from Var to TcType, but can't be helped.
      61bfd5dd
  28. 26 Sep, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-09-26 15:12:33 by simonpj] · e0d750be
      simonpj authored
      ------------------
      		Simon's big commit
      		------------------
      
      This commit, which I don't think I can sensibly do piecemeal, consists
      of the things I've been doing recently, mainly directed at making
      Manuel, George, and Marcin happier with RULES.
      
      
      Reogranise the simplifier
      ~~~~~~~~~~~~~~~~~~~~~~~~~
      1. The simplifier's environment is now an explicit parameter.  This
      makes it a bit easier to figure out where it is going.
      
      2. Constructor arguments can now be arbitrary expressions, except
      when the application is the RHS of a let(rec).  This makes it much
      easier to match rules like
      
      	RULES
      	    "foo"  f (h x, g y) = f' x y
      
      In the simplifier, it's Simplify.mkAtomicArgs that ANF-ises a
      constructor application where necessary.  In the occurrence analyser,
      there's a new piece of context info (OccEncl) to say whether a
      constructor app is in a place where it should be in ANF.  (Unless
      it knows this it'll give occurrence info which will inline the
      argument back into the constructor app.)
      
      3. I'm experimenting with doing the "float-past big lambda" transformation
      in the full laziness pass, rather than mixed in with the simplifier (was
      tryRhsTyLam).
      
      4.  Arrange that
      	case (coerce (S,T) (x,y)) of ...
      will simplify.  Previous it didn't.
      A local change to CoreUtils.exprIsConApp_maybe.
      
      5. Do a better job in CoreUtils.exprEtaExpandArity when there's an
      error function in one branch.
      
      
      Phase numbers, RULES, and INLINE pragmas
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      1.  Phase numbers decrease from N towards zero (instead of increasing).
      This makes it easier to add new earlier phases, which is what users want
      to do.
      
      2.  RULES get their own phase number, N, and are disabled in phases before N.
      
      e.g. 	{-# RULES "foo" [2] forall x y.  f (x,y) = f' x y #-}
      
      Note the [2], which says "only active in phase 2 and later".
      
      3.  INLINE and NOINLINE pragmas have a phase number to.  This is now treated
      in just the same way as the phase number on RULE; that is, the Id is not inlined
      in phases earlier than N.  In phase N and later the Id *may* be inlined, and
      here is where INLINE and NOINLINE differ: INLNE makes the RHS look small, so
      as soon as it *may* be inlined it probably *will* be inlined.
      
      The syntax of the phase number on an INLINE/NOINLINE pragma has changed to be
      like the RULES case (i.e. in square brackets).  This should also make sure
      you examine all such phase numbers; many will need to change now the numbering
      is reversed.
      
      Inlining Ids is no longer affected at all by whether the Id appears on the
      LHS of a rule.  Now it's up to the programmer to put a suitable INLINE/NOINLINE
      pragma to stop it being inlined too early.
      
      
      Implementation notes:
      
      *  A new data type, BasicTypes.Activation says when a rule or inline pragma
      is active.   Functions isAlwaysActive, isNeverActive, isActive, do the
      obvious thing (all in BasicTypes).
      
      * Slight change in the SimplifierSwitch data type, which led to a lot of
      simplifier-specific code moving from CmdLineOpts to SimplMonad; a Good Thing.
      
      * The InlinePragma in the IdInfo of an Id is now simply an Activation saying
      when the Id can be inlined.  (It used to be a rather bizarre pair of a
      Bool and a (Maybe Phase), so this is much much easier to understand.)
      
      * The simplifier has a "mode" environment switch, replacing the old
      black list.  Unfortunately the data type decl has to be in
      CmdLineOpts, because it's an argument to the CoreDoSimplify switch
      
          data SimplifierMode = SimplGently | SimplPhase Int
      
      Here "gently" means "no rules, no inlining".   All the crucial
      inlining decisions are now collected together in SimplMonad
      (preInlineUnconditionally, postInlineUnconditionally, activeInline,
      activeRule).
      
      
      Specialisation
      ~~~~~~~~~~~~~~
      1.  Only dictionary *functions* are made INLINE, not dictionaries that
      have no parameters.  (This inline-dictionary-function thing is Marcin's
      idea and I'm still not sure whether it's a good idea.  But it's definitely
      a Bad Idea when there are no arguments.)
      
      2.  Be prepared to specialise an INLINE function: an easy fix in
      Specialise.lhs
      
      But there is still a problem, which is that the INLINE wins
      at the call site, so we don't use the specialised version anyway.
      I'm still unsure whether it makes sense to SPECIALISE something
      you want to INLINE.
      
      
      
      
      
      Random smaller things
      ~~~~~~~~~~~~~~~~~~~~~~
      
      * builtinRules (there was only one, but may be more) in PrelRules are now
        incorporated.   They were being ignored before...
      
      * OrdList.foldOL -->  OrdList.foldrOL, OrdList.foldlOL
      
      * Some tidying up of the tidyOpenTyVar, tidyTyVar functions.  I've
        forgotten exactly what!
      e0d750be
  29. 23 Aug, 2001 2 commits
    • simonpj's avatar
      [project @ 2001-08-23 15:05:52 by simonpj] · f62fd70d
      simonpj authored
      More instance-gate fiddling.  This must be one of the most
      tiremsome bits of the entire compiler, and I appear to be
      incapable of modifying it without getting it wrong at least
      once.
      
      Still, this commit does tidy things up a bit.
      
      * The type renamers (rnHsType, etc) have moved from RnSource
        into a new module RnTypes.
      
      * This breaks a couple of loops, and lets us nuke RnSource.hi-boot.
        Hurrah!
      
      Simon
      f62fd70d
    • simonpj's avatar
      [project @ 2001-08-23 09:54:45 by simonpj] · 98bf5734
      simonpj authored
      --------------------------------------------------
      	Be a bit more liberal when slurping instance decls
      	--------------------------------------------------
      
      Functional dependencies have (as usual) made things more complicated
      
      Suppose an interface file contains
      	interface A where
      	  class C a b | a->b where op :: a->b
      	  instance C Foo Baz where ...
      
      Now we are compiling
      	module B where
      	  import A
      	  t = op (v::Foo)
      
      Should we slurp the instance decl, even though Baz is nowhere mentioned
      in module B?  YES!  Because of the fundep, the (C Foo ?) part is enough to
      select this instance decl, and the Baz part follows.
      
      Rather than take fundeps into account "properly", we just slurp
      if C is visible and *any one* of the Names in the types
      This is a slightly brutal approximation, but most instance decls
      are regular H98 ones and it's perfect for them.
      
      Changes:
      
        HscTypes:
      	generalise the types of GatedDecl a bit
      
        RnHiFiles.loadInstDecl, RnHiFiles.loadRule, RnIfaces.selectGated:
      	the meat of the solution
      
        RdrName, OccName etc:
      	some consequential wibbles
      98bf5734
  30. 14 Aug, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-08-14 06:35:56 by simonpj] · 2767767f
      simonpj authored
      1. Arrange that w/w records unfoldings
         And that the simplifier preserves them
      
      2. Greatly improve structure of checking user types in the typechecker
         Main changes:
      	TcMType.checkValidType checks for a valid type
      	TcMonoType.tcHsSigType uses checkValidType
      	Type and class decls use TcMonoType.tcHsType (which does not
      		check for validity) inside the knot in TcTyClsDecls,
      		and then runs TcTyDecls.checkValidTyCon
      		or TcClassDcl.checkValidClass to check for validity
      		once the knot is tied
      2767767f
  31. 23 Jul, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-07-23 10:54:46 by simonpj] · f6cd95ff
      simonpj authored
      ---------------------------------
      	Switch to the new demand analyser
      	---------------------------------
      
      This commit makes the new demand analyser the main beast,
      with the old strictness analyser as a backup.  When
      DEBUG is on, the old strictness analyser is run too, and the
      results compared.
      
      WARNING: this isn't thorougly tested yet, so expect glitches.
      Delay updating for a few days if the HEAD is mission critical
      for you.
      
      But do try it out.  I'm away for 2.5 weeks from Thursday, so
      it would be good to shake out any glaring bugs before then.
      f6cd95ff
  32. 11 Jun, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-06-11 12:24:51 by simonpj] · 2c6d73e2
      simonpj authored
      --------------------------------------
      	Tidy up and improve "pattern contexts"
      	--------------------------------------
      
      In various places (renamer, typechecker, desugarer) we need to know
      what the context of a pattern match is (case expression, function defn,
      let binding, etc).  This commit tidies up the story quite a bit.  I
      think it represents a net decrease in code, and certainly it improves the
      error messages from:
      
      	f x x = 3
      
      Prevsiously we got a message like "Conflicting bindings for x in a pattern match",
      but not it says "..in a defn of function f".
      
      WARNING: the tidy up had a more global effect than I originally expected,
      so it's possible that some other error messages look a bit peculiar.  They
      should be easy to fix, but tell us!
      2c6d73e2
  33. 24 May, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-05-24 13:59:09 by simonpj] · cbdeae8f
      simonpj authored
      ------------------------------------------------------
      	More stuff towards generalising 'foreign' declarations
      	------------------------------------------------------
      
      This is the second step towards generalising 'foreign' declarations to
      handle langauges other than C.  Now I can handle
      
        foreign import dotnet type T
        foreign import dotnet "void Foo.Baz.f( T )" f :: T -> IO ()
      
      
      
      			** WARNING **
      	I believe that all the foreign stuff for C should
      	work exactly as before, but I have not tested it
      	thoroughly.  Sven, Manuel, Marcin: please give it a
      	whirl and compare old with new output.
      
      
      Lots of fiddling around with data types.  The main changes are
      
      * HsDecls.lhs
      	The ForeignDecl type and its friends
      	Note also the ForeignType constructor to TyClDecl
      
      * ForeignCall.lhs
      	Here's where the stuff that survives right through
      	compilation lives
      
      * TcForeign.lhs DsForeign.lhs
      	Substantial changes driven by the new data types
      
      * Parser.y ParseIface.y RnSource
      	Just what you'd expect
      cbdeae8f
  34. 22 May, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-05-22 13:43:14 by simonpj] · f16228e4
      simonpj authored
      -------------------------------------------
      	Towards generalising 'foreign' declarations
      	-------------------------------------------
      
      This is a first step towards generalising 'foreign' declarations to
      handle langauges other than C.  Quite a lot of files are touched,
      but nothing has really changed.  Everything should work exactly as
      before.
      
      	But please be on your guard for ccall-related bugs.
      
      Main things
      
      Basic data types: ForeignCall.lhs
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * Remove absCSyn/CallConv.lhs
      
      * Add prelude/ForeignCall.lhs.  This defines the ForeignCall
        type and its variants
      
      * Define ForeignCall.Safety to say whether a call is unsafe
        or not (was just a boolean).  Lots of consequential chuffing.
      
      * Remove all CCall stuff from PrimOp, and put it in ForeignCall
      
      
      Take CCallOp out of the PrimOp type (where it was always a glitch)
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * Add IdInfo.FCallId variant to the type IdInfo.GlobalIdDetails,
      	along with predicates Id.isFCallId, Id.isFCallId_maybe
      
      * Add StgSyn.StgOp, to sum PrimOp with FCallOp, because it
        *is* useful to sum them together in Stg and AbsC land.  If
        nothing else, it minimises changes.
      
      
      Also generally rename "CCall" stuff to "FCall" where it's generic
      to all foreign calls.
      f16228e4
  35. 18 May, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-05-18 08:46:18 by simonpj] · b4775e5e
      simonpj authored
      -----------------------------
      	Get unbox-strict-fields right
      	-----------------------------
      
      The problem was that when a library was compiled *without* -funbox-strict-fields,
      and the main program was compiled *with* that flag, we were wrongly treating
      the fields of imported data types as unboxed.
      
      To fix this I added an extra constructor to StrictnessMark to express whether
      the "!" annotation came from an interface file (don't fiddle) or a source
      file (decide whether to unbox).
      
      On the way I tided things up:
      
      * StrictnessMark moves to Demand.lhs, and doesn't have the extra DataCon
        fields that kept it in DataCon before.
      
      * HsDecls.BangType has one constructor, not three, with a StrictnessMark field.
      
      * DataCon keeps track of its strictness signature (dcRepStrictness), but not
        its "user strict marks" (which were never used)
      
      * All the functions, like getUniquesDs, that used to take an Int saying how
        many uniques to allocate, now return an infinite list. This saves arguments
        and hassle.  But it involved touching quite a few files.
      
      * rebuildConArgs takes a list of Uniques to use as its unique supply.  This
        means I could combine DsUtils.rebuildConArgs with MkId.rebuildConArgs
        (hooray; the main point of the previous change)
      
      
      I also tidied up one or two error messages
      b4775e5e
  36. 03 May, 2001 1 commit
  37. 30 Apr, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-04-30 10:51:18 by simonpj] · e7b69c55
      simonpj authored
      -----------------------------
      	Better filtering for warnings
      	-----------------------------
      
      * Add Opt_WarnMisc, to enable warnings not otherwise covered by Opt_Warn*
        in the renamer
      
      * Add RnMonad.ifOptRn :: DynFlag -> RnM d a -> RnM d ()
        and use it many places instead of the clumsy direct code
      e7b69c55
  38. 05 Apr, 2001 2 commits
    • simonpj's avatar
      [project @ 2001-04-05 11:54:37 by simonpj] · 197a5ee7
      simonpj authored
      Make type synonyms work right in H98
      197a5ee7
    • simonpj's avatar
      [project @ 2001-04-05 11:31:26 by simonpj] · 11197236
      simonpj authored
      --------------------------------
      	Better grouping for ty/cls decls
      	--------------------------------
      
      When finding mutually-recursive groups of type and class decls,
      we shouldn't include classes mentioned in a deriving clause as
      edges. E.g.
      
      	class Eq a where ...
      
      	data Bool = True | False deriving( Eq )
      
      Eq and Bool are not mutually recursive.
      
      The edges are computed by RnHsSyn.tyClDeclFVs, so we remove the
      derivings from there.
      
      There a consequential fix in RnSource.rnSourceDecl
      11197236