1. 16 Dec, 2003 1 commit
  2. 10 Dec, 2003 2 commits
    • simonmar's avatar
      [project @ 2003-12-10 17:25:12 by simonmar] · c7b38930
      simonmar authored
      Cleanups:
      
      - Move the collect* functions from HsSyn into HsUtils.  Check that we
        have a clean separation of utilties over HsSyn, with the generic
        versions in HsUtils, and the specific versions in RdrHsSyn, RnHsSyn
        and TcHsSyn as appropriate.
      
      - Remove the RdrBinding data type, which was really just a nested list
        with O(1) append, and use OrdList instead.  This makes it much clearer
        that there's nothing strange going on.
      
      - Various other minor cleanups.
      c7b38930
    • simonmar's avatar
      [project @ 2003-12-10 14:15:16 by simonmar] · 55042138
      simonmar authored
      Add accurate source location annotations to HsSyn
      -------------------------------------------------
      
      Every syntactic entity in HsSyn is now annotated with a SrcSpan, which
      details the exact beginning and end points of that entity in the
      original source file.  All honest compilers should do this, and it was
      about time GHC did the right thing.
      
      The most obvious benefit is that we now have much more accurate error
      messages; when running GHC inside emacs for example, the cursor will
      jump to the exact location of an error, not just a line somewhere
      nearby.  We haven't put a huge amount of effort into making sure all
      the error messages are accurate yet, so there could be some tweaking
      still needed, although the majority of messages I've seen have been
      spot-on.
      
      Error messages now contain a column number in addition to the line
      number, eg.
      
         read001.hs:25:10: Variable not in scope: `+#'
      
      To get the full text span info, use the new option -ferror-spans.  eg.
      
         read001.hs:25:10-11: Variable not in scope: `+#'
      
      I'm not sure whether we should do this by default.  Emacs won't
      understand the new error format, for one thing.
      
      In a more elaborate editor setting (eg. Visual Studio), we can arrange
      to actually highlight the subexpression containing an error.  Eventually
      this information will be used so we can find elements in the abstract
      syntax corresponding to text locations, for performing high-level editor
      functions (eg. "tell me the type of this expression I just highlighted").
      
      Performance of the compiler doesn't seem to be adversely affected.
      Parsing is still quicker than in 6.0.1, for example.
      
      Implementation:
      
      This was an excrutiatingly painful change to make: both Simon P.J. and
      myself have been working on it for the last three weeks or so.  The
      basic changes are:
      
       - a new datatype SrcSpan, which represents a beginning and end position
         in a source file.
      
       - To reduce the pain as much as possible, we also defined:
      
            data Located e = L SrcSpan e
      
       - Every datatype in HsSyn has an equivalent Located version.  eg.
      
            type LHsExpr id = Located (HsExpr id)
      
         and pretty much everywhere we used to use HsExpr we now use
         LHsExpr.  Believe me, we thought about this long and hard, and
         all the other options were worse :-)
      
      
      Additional changes/cleanups we made at the same time:
      
        - The abstract syntax for bindings is now less arcane.  MonoBinds
          and HsBinds with their built-in list constructors have gone away,
          replaced by HsBindGroup and HsBind (see HsSyn/HsBinds.lhs).
      
        - The various HsSyn type synonyms have now gone away (eg. RdrNameHsExpr,
          RenamedHsExpr, and TypecheckedHsExpr are now HsExpr RdrName,
          HsExpr Name, and HsExpr Id respectively).
      
        - Utilities over HsSyn are now collected in a new module HsUtils.
          More stuff still needs to be moved in here.
      
        - MachChar now has a real Char instead of an Int.  All GHC versions that
          can compile GHC now support 32-bit Chars, so this was a simplification.
      55042138
  3. 03 Nov, 2003 1 commit
  4. 09 Oct, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-10-09 11:58:39 by simonpj] · 98688c6e
      simonpj authored
      -------------------------
      		GHC heart/lung transplant
      		-------------------------
      
      This major commit changes the way that GHC deals with importing
      types and functions defined in other modules, during renaming and
      typechecking.  On the way I've changed or cleaned up numerous other
      things, including many that I probably fail to mention here.
      
      Major benefit: GHC should suck in many fewer interface files when
      compiling (esp with -O).  (You can see this with -ddump-rn-stats.)
      
      It's also some 1500 lines of code shorter than before.
      
      **	So expect bugs!  I can do a 3-stage bootstrap, and run
      **	the test suite, but you may be doing stuff I havn't tested.
      ** 	Don't update if you are relying on a working HEAD.
      
      
      In particular, (a) External Core and (b) GHCi are very little tested.
      
      	But please, please DO test this version!
      
      
      	------------------------
      		Big things
      	------------------------
      
      Interface files, version control, and importing declarations
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      * There is a totally new data type for stuff that lives in interface files:
      	Original names			IfaceType.IfaceExtName
      	Types				IfaceType.IfaceType
      	Declarations (type,class,id)	IfaceSyn.IfaceDecl
      	Unfoldings			IfaceSyn.IfaceExpr
        (Previously we used HsSyn for type/class decls, and UfExpr for unfoldings.)
        The new data types are in iface/IfaceType and iface/IfaceSyn.  They are
        all instances of Binary, so they can be written into interface files.
        Previous engronkulation concering the binary instance of RdrName has
        gone away -- RdrName is not an instance of Binary any more.  Nor does
        Binary.lhs need to know about the ``current module'' which it used to,
        which made it specialised to GHC.
      
        A good feature of this is that the type checker for source code doesn't
        need to worry about the possibility that we might be typechecking interface
        file stuff.  Nor does it need to do renaming; we can typecheck direct from
        IfaceSyn, saving a whole pass (module TcIface)
      
      * Stuff from interface files is sucked in *lazily*, rather than being eagerly
        sucked in by the renamer. Instead, we use unsafeInterleaveIO to capture
        a thunk for the unfolding of an imported function (say).  If that unfolding
        is every pulled on, TcIface will scramble over the unfolding, which may
        in turn pull in the interface files of things mentioned in the unfolding.
      
        The External Package State is held in a mutable variable so that it
        can be side-effected by this lazy-sucking-in process (which may happen
        way later, e.g. when the simplifier runs).   In effect, the EPS is a kind
        of lazy memo table, filled in as we suck things in.  Or you could think
        of it as a global symbol table, populated on demand.
      
      * This lazy sucking is very cool, but it can lead to truly awful bugs. The
        intent is that updates to the symbol table happen atomically, but very bad
        things happen if you read the variable for the table, and then force a
        thunk which updates the table.  Updates can get lost that way. I regret
        this subtlety.
      
        One example of the way it showed up is that the top level of TidyPgm
        (which updates the global name cache) to be much more disciplined about
        those updates, since TidyPgm may itself force thunks which allocate new
        names.
      
      * Version numbering in interface files has changed completely, fixing
        one major bug with ghc --make.  Previously, the version of A.f changed
        only if A.f's type and unfolding was textually different.  That missed
        changes to things that A.f's unfolding mentions; which was fixed by
        eagerly sucking in all of those things, and listing them in the module's
        usage list.  But that didn't work with --make, because they might have
        been already sucked in.
      
        Now, A.f's version changes if anything reachable from A.f (via interface
        files) changes.  A module with unchanged source code needs recompiling
        only if the versions of any of its free variables changes. [This isn't
        quite right for dictionary functions and rules, which aren't mentioned
        explicitly in the source.  There are extensive comments in module MkIface,
        where all version-handling stuff is done.]
      
      * We don't need equality on HsDecls any more (because they aren't used in
        interface files).  Instead we have a specialised equality for IfaceSyn
        (eqIfDecl etc), which uses IfaceEq instead of Bool as its result type.
        See notes in IfaceSyn.
      
      * The horrid bit of the renamer that tried to predict what instance decls
        would be needed has gone entirely.  Instead, the type checker simply
        sucks in whatever instance decls it needs, when it needs them.  Easy!
      
        Similarly, no need for 'implicitModuleFVs' and 'implicitTemplateHaskellFVs'
        etc.  Hooray!
      
      
      Types and type checking
      ~~~~~~~~~~~~~~~~~~~~~~~
      * Kind-checking of types is far far tidier (new module TcHsTypes replaces
        the badly-named TcMonoType).  Strangely, this was one of my
        original goals, because the kind check for types is the Right Place to
        do type splicing, but it just didn't fit there before.
      
      * There's a new representation for newtypes in TypeRep.lhs.  Previously
        they were represented using "SourceTypes" which was a funny compromise.
        Now they have their own constructor in the Type datatype.  SourceType
        has turned back into PredType, which is what it used to be.
      
      * Instance decl overlap checking done lazily.  Consider
      	instance C Int b
      	instance C a Int
        These were rejected before as overlapping, because when seeking
        (C Int Int) one couldn't tell which to use.  But there's no problem when
        seeking (C Bool Int); it can only be the second.
      
        So instead of checking for overlap when adding a new instance declaration,
        we check for overlap when looking up an Inst.  If we find more than one
        matching instance, we see if any of the candidates dominates the others
        (in the sense of being a substitution instance of all the others);
        and only if not do we report an error.
      
      
      
      	------------------------
      	     Medium things
      	------------------------
      
      * The TcRn monad is generalised a bit further.  It's now based on utils/IOEnv.lhs,
        the IO monad with an environment.  The desugarer uses the monad too,
        so that anything it needs can get faulted in nicely.
      
      * Reduce the number of wired-in things; in particular Word and Integer
        are no longer wired in.  The latter required HsLit.HsInteger to get a
        Type argument.  The 'derivable type classes' data types (:+:, :*: etc)
        are not wired in any more either (see stuff about derivable type classes
        below).
      
      * The PersistentComilerState is now held in a mutable variable
        in the HscEnv.  Previously (a) it was passed to and then returned by
        many top-level functions, which was painful; (b) it was invariably
        accompanied by the HscEnv.  This change tidies up top-level plumbing
        without changing anything important.
      
      * Derivable type classes are treated much more like 'deriving' clauses.
        Previously, the Ids for the to/from functions lived inside the TyCon,
        but now the TyCon simply records their existence (with a simple boolean).
        Anyone who wants to use them must look them up in the environment.
      
        This in turn makes it easy to generate the to/from functions (done
        in types/Generics) using HsSyn (like TcGenDeriv for ordinary derivings)
        instead of CoreSyn, which in turn means that (a) we don't have to figure
        out all the type arguments etc; and (b) it'll be type-checked for us.
        Generally, the task of generating the code has become easier, which is
        good for Manuel, who wants to make it more sophisticated.
      
      * A Name now says what its "parent" is. For example, the parent of a data
        constructor is its type constructor; the parent of a class op is its
        class.  This relationship corresponds exactly to the Avail data type;
        there may be other places we can exploit it.  (I made the change so that
        version comparison in interface files would be a bit easier; but in
        fact it tided up other things here and there (see calls to
        Name.nameParent).  For example, the declaration pool, of declararations
        read from interface files, but not yet used, is now keyed only by the 'main'
        name of the declaration, not the subordinate names.
      
      * New types OccEnv and OccSet, with the usual operations.
        OccNames can be efficiently compared, because they have uniques, thanks
        to the hashing implementation of FastStrings.
      
      * The GlobalRdrEnv is now keyed by OccName rather than RdrName.  Not only
        does this halve the size of the env (because we don't need both qualified
        and unqualified versions in the env), but it's also more efficient because
        we can use a UniqFM instead of a FiniteMap.
      
        Consequential changes to Provenance, which has moved to RdrName.
      
      * External Core remains a bit of a hack, as it was before, done with a mixture
        of HsDecls (so that recursiveness and argument variance is still inferred),
        and IfaceExprs (for value declarations).  It's not thoroughly tested.
      
      
      	------------------------
      	     Minor things
      	------------------------
      
      * DataCon fields dcWorkId, dcWrapId combined into a single field
        dcIds, that is explicit about whether the data con is a newtype or not.
        MkId.mkDataConWorkId and mkDataConWrapId are similarly combined into
        MkId.mkDataConIds
      
      * Choosing the boxing strategy is done for *source* type decls only, and
        hence is now in TcTyDecls, not DataCon.
      
      * WiredIn names are distinguished by their n_sort field, not by their location,
        which was rather strange
      
      * Define Maybes.mapCatMaybes :: (a -> Maybe b) -> [a] -> [b]
        and use it here and there
      
      * Much better pretty-printing of interface files (--show-iface)
      
      Many, many other small things.
      
      
      	------------------------
      	     File changes
      	------------------------
      * New iface/ subdirectory
      * Much of RnEnv has moved to iface/IfaceEnv
      * MkIface and BinIface have moved from main/ to iface/
      * types/Variance has been absorbed into typecheck/TcTyDecls
      * RnHiFiles and RnIfaces have vanished entirely.  Their
        work is done by iface/LoadIface
      * hsSyn/HsCore has gone, replaced by iface/IfaceSyn
      * typecheck/TcIfaceSig has gone, replaced by iface/TcIface
      * typecheck/TcMonoType has been renamed to typecheck/TcHsType
      * basicTypes/Var.hi-boot and basicTypes/Generics.hi-boot have gone altogether
      98688c6e
  5. 23 Sep, 2003 1 commit
  6. 23 Jun, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-06-23 10:35:15 by simonpj] · d28ba8c8
      simonpj authored
      -------------------
      	Dealing with 'main'
      	-------------------
      
      1.  In GHC 6.0, a module with no "module Main ... where" header
          elicited an error "main is not in scope" if 'main' is not defined.  We
          don't want this behaviour in GHCi.  This happened because the parser
          expanded the (absent) header to "module Main( main ) where", and the
          'main' in the export list isn't.
      
      Solution: elaborate HsModule to record whether the 'module ..." header was
      given explicitly by the user or not.
      
      
      2.  Add a -main-is flag, and document it, so that you can have a 'main' function
      that is not Main.main.  Summary of changes
      
      * The -main-is flag nominates what the main function is to be (see the documentation).
      	No -main-is flag 	says that the main function is Main.main
      	-main-is Foo.baz	says that the main function is Foo.baz
      	-main-is Foo		says that the main function is Foo.main
      	-main-is baz		says that the main function is Main.baz
      
        Let's say  you say -main-is Foo.baz
      
      * TcRnDriver injects the extra definition
      	$Mian.main :: IO t
      	$Main.main = baz
        in the module Foo.   Note the naming, which is a bit different than before;
        previously the extra defn was for Main.$main.  The RTS invokes zdMain_main_closure.
      
      * CodeGen injects an extra initialisation block into module Foo, thus
      	stginit_zdMain {
      		stginit_Foo
      	}
        That ensures that the RTS can initialise stginit_zdMain.
      d28ba8c8
  7. 02 Jun, 2003 1 commit
  8. 06 May, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-05-06 10:25:32 by simonpj] · e4abae1d
      simonpj authored
      -------------------------------------
      		Main module exports
      	-------------------------------------
      
      Make it so that
      
         	    module Main where ....
      
      exports everything defined in Main, as the report says it should.
      e4abae1d
  9. 21 Feb, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-02-21 13:27:53 by simonpj] · 84ed91ab
      simonpj authored
      -------------------------------------
      	Improve the "unused binding" warnings
      	-------------------------------------
      
      We've had a succession of hacks for reporting warnings for
      unused bindings.  Consider
      
      	module M( f ) where
      
       	f x = x
      
      	g x = g x + h x
      	h x = x
      
      Here, g mentions itself and h, but is not itself mentioned. So
      really both g and h are dead code.  We've been getting this wrong
      for ages, and every hack so far has failed on some simple programs.
      
      This commit does a much better job.  The renamer applied to a bunch
      of bindings returns a NameSet.DefUses, which is a dependency-ordered
      lists of def/use pairs.  It's documented in NameSet.
      Given this, we can work out precisely what is not used, in a nice
      tidy way.
      
      It's less convenient in the case of type and class declarations, because
      the strongly-connected-component analysis can span module boundaries.
      So things are pretty much as they were for these.
      
      
      As usual, there was a lot of chuffing around tidying things up.
      I havn't tested it at all thoroughly yet.
      
      Various unrelated import-decl-pruning has been done too.
      84ed91ab
  10. 12 Feb, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-02-12 15:01:31 by simonpj] · 42b63073
      simonpj authored
      -------------------------------------
        Big upheaval to the way that constructors are named
      	-------------------------------------
      
      This commit enshrines the new story for constructor names.  We could never
      really get External Core to work nicely before, but now it does.
      
      The story is laid out in detail in the Commentary
      	ghc/docs/comm/the-beast/data-types.html
      so I will not repeat it here.
      
      	[Manuel: the commentary isn't being updated, apparently.]
      
      However, the net effect is that in Core and in External Core, contructors look
      like constructors, and the way things are printed is all consistent.
      
      It is a fairly pervasive change (which is why it has been so long postponed),
      but I hope the question is now finally closed.
      
      All the libraries compile etc, and I've run many tests, but doubtless there will
      be some dark corners.
      42b63073
  11. 10 Jan, 2003 1 commit
  12. 09 Jan, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-01-09 16:15:51 by simonpj] · ba580284
      simonpj authored
      --------------------------
      	Fix export-calculation bug
      	--------------------------
      
      Ross points out that in
       	module M where
       	import List as M
       	sort = "foo"
      
      there is no conflict in the export list. GHC used to treat this
      like
      
      	module M( module M ) where ...
      
      which is wrong, wrong, wrong.
      
      Now fixed.   Test in modules/mod200.hs
      
      Some other small tidying up (notably in GRE.gre_parent).
      ba580284
  13. 06 Nov, 2002 1 commit
  14. 05 Nov, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-11-05 11:42:48 by simonpj] · c4d85183
      simonpj authored
      ------------------
      		Fix module exports
      		------------------
      
      GHC was doing the wrong thing when it came to detecting conflicts
      on exports from 'module M' items.  This commit fixes it.
      
      There's a test in rename/should_fail/rnfail040
      c4d85183
  15. 25 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-25 15:23:03 by simonpj] · 4ef18ea2
      simonpj authored
      ------------------------
      	More dependency fiddling
      	------------------------
      
      	WARNING: Interface file format has changed (again)
      		 You need to 'make clean' in all library code
      
      * Orphan modules are now kept separately
        Home-package dependencies now contain only home-package dependencies!
        See HscTypes.Dependencies
      
      * Linker now uses the dependencies to do dynamic linking
      
      Result: Template Haskell should work even without --make (not yet tested)
      4ef18ea2
  16. 24 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-24 14:17:46 by simonpj] · e0445ffa
      simonpj authored
      ------------------------------------------
      	1. New try and module and package dependencies
      	2. OrigNameCache always contains final info
      	------------------------------------------
      
      These things nearly complete sorting out the incremental
      linking problem that started us off!
      
      1. This commit separates two kinds of information:
      
        (a) HscTypes.Dependencies:
      	What (i)  home-package modules, and
      	     (ii) other packages
            this module depends on, transitively.
      
            That is, to link the module, it should be enough
            to link the dependent modules and packages (plus
            any C stubs etc).
      
            Along with this info we record whether the dependent module
            is (a) a boot interface or (b) an orphan module.  So in
            fact (i) can contain non-home-package modules, namely the
            orphan ones in other packages (sigh).
      
        (b) HscTypes.Usage:
            What version of imported things were used to
            actually compile the module.  This info is used for
            recompilation control only.
      
      
      
      2. The Finder now returns a correct Module (incl package indicator)
      first time, so we can install the absolutely final Name in the
      OrigNameCache when we first come across an occurrence of that name,
      even if it's only an occurrence in an unfolding in some other interface
      file.  This is much tidier.
      
      As a result Module.lhs is much cleaner
      	No DunnoYet
      	No mkVanillaModule
      ALl very joyful stuff.
      e0445ffa
  17. 11 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-11 14:46:02 by simonpj] · cbb5beb0
      simonpj authored
      ------------------------------------------
      	Implement reification for Template Haskell
      	------------------------------------------
      
      This is entirely un-tested, but I don't think it'll break non-TH stuff.
      
      Implements
      	reifyDecl T :: Dec	-- Data type T
      	reifyDecl C :: Dec	-- Class C
      	reifyType f :: Typ	-- Function f
      
      I hope.
      cbb5beb0
  18. 09 Oct, 2002 3 commits
  19. 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
  20. 25 Sep, 2002 1 commit
  21. 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
  22. 05 Apr, 2002 1 commit
  23. 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
  24. 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
  25. 12 Dec, 2001 1 commit
  26. 07 Dec, 2001 3 commits
    • simonpj's avatar
      [project @ 2001-12-07 17:33:26 by simonpj] · 8cc5cc27
      simonpj authored
      ----------------------------
      	More jiggling in the renamer
      	----------------------------
      
      I was a little hasty before.  (Thanks Sigbjorn for finding
      this.)  This commit tidies up the handling of AvailEnvs.
      Principally:
      
        * filterImports now deals completely with hiding
          (before it handed off part of the job to mkGlobalRdrEnv)
      
        * The AvailEnv in an ExportAvails does not have class ops and
          data constructors in its domain.  This makes plusExportAvails
          more efficient, but the main thing is that it collects things
          up right.  (Previously, if we had
      	import M( C )
      	import M( op )
          then we got an AvailEnv which had C |-> AvailTC C [C]
          (no 'op').
      
        * In Rename, we do need a "filled-out" version of the overall
          AvailEnv, full_avail_env, which we construct on the spot in 'rename'.
      8cc5cc27
    • sof's avatar
      [project @ 2001-12-07 08:12:53 by sof] · c5ba8422
      sof authored
      mkExportAvails: computing the AvailEnv is rather delicate
      c5ba8422
    • sof's avatar
      [project @ 2001-12-07 07:37:43 by sof] · 24279879
      sof authored
      Tidyup - previous instance-decl commit fell a bit short:
      
       * RnEnv.lookupInstDeclBndr unceremoniously fell over when passed
         an out-of-scope class name.
      
       * the AvailEnv carried around didn't common up type/class info
         (i.e.,  AvailTCs), but rather type/class and method/label names,
         causing the renamer to (semi)randomly report instance methods as
         being out-of-scope in the presence of multiple imports for a module.
      
       * didn't support 'hiding' of class / method names (for the purposes
         of checking instance decls).
      24279879
  27. 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
  28. 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
  29. 12 Jul, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-07-12 14:51:28 by simonpj] · 6d1815b0
      simonpj authored
      Fix the module import story to match what the Revised
      Haskell Report says
      
      1. 	Don't import qualified names of things that aren't imported
      
      2.	Fix a bug that meant
      		import A hiding( D )
      	where D is a data constructor, didn't work.
      	[The fix is to use IEVar not IEThingAbs in the
      	want_hiding case of get_item in RnNames.filterImports
      6d1815b0
  30. 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
  31. 30 Apr, 2001 2 commits
    • panne's avatar
      [project @ 2001-04-30 13:50:59 by panne] · c66b73ec
      panne authored
      o=>O:-)
      c66b73ec
    • 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
  32. 08 Mar, 2001 1 commit
    • simonpj's avatar
      [project @ 2001-03-08 12:07:38 by simonpj] · 51a571c0
      simonpj authored
      --------------------
      	A major hygiene pass
      	--------------------
      
      1. The main change here is to
      
      	Move what was the "IdFlavour" out of IdInfo,
      	and into the varDetails field of a Var
      
         It was a mess before, because the flavour was a permanent attribute
         of an Id, whereas the rest of the IdInfo was ephemeral.  It's
         all much tidier now.
      
         Main places to look:
      
      	   Var.lhs	Defn of VarDetails
      	   IdInfo.lhs	Defn of GlobalIdDetails
      
         The main remaining infelicity is that SpecPragmaIds are right down
         in Var.lhs, which seems unduly built-in for such an ephemeral thing.
         But that is no worse than before.
      
      
      2. Tidy up the HscMain story a little.  Move mkModDetails from MkIface
         into CoreTidy (where it belongs more nicely)
      
         This was partly forced by (1) above, because I didn't want to make
         DictFun Ids into a separate kind of Id (which is how it was before).
         Not having them separate means we have to keep a list of them right
         through, rather than pull them out of the bindings at the end.
      
      3. Add NameEnv as a separate module (to join NameSet).
      
      4. Remove unnecessary {-# SOURCE #-} imports from FieldLabel.
      51a571c0
  33. 01 Mar, 2001 1 commit
  34. 28 Feb, 2001 1 commit