1. 31 Jul, 2008 1 commit
  2. 03 Oct, 2007 1 commit
  3. 04 Sep, 2007 1 commit
  4. 03 Sep, 2007 1 commit
  5. 01 Sep, 2007 1 commit
  6. 25 Apr, 2007 1 commit
    • simonpj@microsoft.com's avatar
      Retain inline-pragma information on unfoldings in interface files · d33c0b24
      simonpj@microsoft.com authored
      	WARNING: this patch changes interface-file formats slightly
      	 	 you will need to recompile your libraries
      
      Duncan Coutts wanted to export a function that has a NOINLNE pragma
      in a local let-defintion.  This works fine within a module, but was 
      not surviving across the interface-file serialisation.
      
      http://www.haskell.org/pipermail/glasgow-haskell-users/2007-March/012171.html
      
      Regardless of whether or not he's doing something sensible, it seems
      reasonable to try to retain local-binder IdInfo across interface files.
      This initial patch just retains inline-pragma info, on the grounds that
      other IdInfo can be re-inferred at the inline site.
      
      Interface files get a tiny bit bigger, but it seesm slight.
      
      d33c0b24
  7. 13 Nov, 2006 1 commit
    • Aaron Tomb's avatar
      Fix external core syntax (though not full compilation) · de777ba4
      Aaron Tomb authored
      This patch updates the External Core creator, pretty-printer, and parser to
      agree on a concrete syntax for External Core, including the constructs
      required by the change to System FC. Code to create valid ASTs from External
      Core files will come later, as will bits for renaming, typechecking, and
      desugaring.
      de777ba4
  8. 11 Oct, 2006 1 commit
    • Simon Marlow's avatar
      Interface file optimisation and removal of nameParent · b00b5bc0
      Simon Marlow authored
      This large commit combines several interrelated changes:
      
        - IfaceSyn now contains actual Names rather than the special
          IfaceExtName type.  The binary interface file contains
          a symbol table of Names, where each entry is a (package,
          ModuleName, OccName) triple.  Names in the IfaceSyn point
          to entries in the symbol table.
      
          This reduces the size of interface files, which should
          hopefully improve performance (not measured yet).
      
          The toIfaceXXX functions now do not need to pass around
          a function from Name -> IfaceExtName, which makes that
          code simpler.
      
        - Names now do not point directly to their parents, and the
          nameParent operation has gone away.  It turned out to be hard to
          keep this information consistent in practice, and the parent info
          was only valid in some Names.  Instead we made the following
          changes:
      
          * ImportAvails contains a new field 
                imp_parent :: NameEnv AvailInfo
            which gives the family info for any Name in scope, and
            is used by the renamer when renaming export lists, amongst
            other things.  This info is thrown away after renaming.
      
          * The mi_ver_fn field of ModIface now maps to
            (OccName,Version) instead of just Version, where the
            OccName is the parent name.  This mapping is used when
            constructing the usage info for dependent modules.
            There may be entries in mi_ver_fn for things that are not in
            scope, whereas imp_parent only deals with in-scope things.
      
          * The md_exports field of ModDetails now contains
            [AvailInfo] rather than NameSet.  This gives us
            family info for the exported names of a module.
      
      Also:
      
         - ifaceDeclSubBinders moved to IfaceSyn (seems like the
           right place for it).
      
         - heavily refactored renaming of import/export lists.
      
         - Unfortunately external core is now broken, as it relied on
           IfaceSyn.  It requires some attention.
      b00b5bc0
  9. 05 Oct, 2006 1 commit
  10. 15 Sep, 2006 1 commit
    • chak@cse.unsw.edu.au.'s avatar
      Migrate cvs diff from fptools-assoc branch · afef3973
      chak@cse.unsw.edu.au. authored
      Wed Jul 26 17:46:55 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
        * Migrate cvs diff from fptools-assoc branch
        - Syntactic support for associated types
        - Renamer support for associated types
        - ATs are only allowed with -fglasgow-exts
        - Handle ATs in the type and class declaration kinding knot-tying exercise
      afef3973
  11. 04 Aug, 2006 1 commit
  12. 12 Sep, 2006 1 commit
  13. 25 Jul, 2006 1 commit
    • Simon Marlow's avatar
      Generalise Package Support · 61d2625a
      Simon Marlow authored
      This patch pushes through one fundamental change: a module is now
      identified by the pair of its package and module name, whereas
      previously it was identified by its module name alone.  This means
      that now a program can contain multiple modules with the same name, as
      long as they belong to different packages.
      
      This is a language change - the Haskell report says nothing about
      packages, but it is now necessary to understand packages in order to
      understand GHC's module system.  For example, a type T from module M
      in package P is different from a type T from module M in package Q.
      Previously this wasn't an issue because there could only be a single
      module M in the program.
      
      The "module restriction" on combining packages has therefore been
      lifted, and a program can contain multiple versions of the same
      package.
      
      Note that none of the proposed syntax changes have yet been
      implemented, but the architecture is geared towards supporting import
      declarations qualified by package name, and that is probably the next
      step.
      
      It is now necessary to specify the package name when compiling a
      package, using the -package-name flag (which has been un-deprecated).
      Fortunately Cabal still uses -package-name.
      
      Certain packages are "wired in".  Currently the wired-in packages are:
      base, haskell98, template-haskell and rts, and are always referred to
      by these versionless names.  Other packages are referred to with full
      package IDs (eg. "network-1.0").  This is because the compiler needs
      to refer to entities in the wired-in packages, and we didn't want to
      bake the version of these packages into the comiler.  It's conceivable
      that someone might want to upgrade the base package independently of
      GHC.
      
      Internal changes:
      
        - There are two module-related types:
      
              ModuleName      just a FastString, the name of a module
              Module          a pair of a PackageId and ModuleName
      
          A mapping from ModuleName can be a UniqFM, but a mapping from Module
          must be a FiniteMap (we provide it as ModuleEnv).
      
        - The "HomeModules" type that was passed around the compiler is now
          gone, replaced in most cases by the current package name which is
          contained in DynFlags.  We can tell whether a Module comes from the
          current package by comparing its package name against the current
          package.
      
        - While I was here, I changed PrintUnqual to be a little more useful:
          it now returns the ModuleName that the identifier should be qualified
          with according to the current scope, rather than its original
          module.  Also, PrintUnqual tells whether to qualify module names with
          package names (currently unused).
      
      Docs to follow.
      61d2625a
  14. 24 Jul, 2006 1 commit
  15. 05 Jun, 2006 1 commit
  16. 20 Apr, 2006 1 commit
  17. 07 Apr, 2006 1 commit
    • Simon Marlow's avatar
      Reorganisation of the source tree · 0065d5ab
      Simon Marlow authored
      Most of the other users of the fptools build system have migrated to
      Cabal, and with the move to darcs we can now flatten the source tree
      without losing history, so here goes.
      
      The main change is that the ghc/ subdir is gone, and most of what it
      contained is now at the top level.  The build system now makes no
      pretense at being multi-project, it is just the GHC build system.
      
      No doubt this will break many things, and there will be a period of
      instability while we fix the dependencies.  A straightforward build
      should work, but I haven't yet fixed binary/source distributions.
      Changes to the Building Guide will follow, too.
      0065d5ab
  18. 06 Jan, 2006 1 commit
    • simonmar's avatar
      [project @ 2006-01-06 16:30:17 by simonmar] · 9d7da331
      simonmar authored
      Add support for UTF-8 source files
      
      GHC finally has support for full Unicode in source files.  Source
      files are now assumed to be UTF-8 encoded, and the full range of
      Unicode characters can be used, with classifications recognised using
      the implementation from Data.Char.  This incedentally means that only
      the stage2 compiler will recognise Unicode in source files, because I
      was too lazy to port the unicode classifier code into libcompat.
      
      Additionally, the following synonyms for keywords are now recognised:
      
        forall symbol 	(U+2200)	forall
        right arrow   	(U+2192)	->
        left arrow   		(U+2190)	<-
        horizontal ellipsis 	(U+22EF)	..
      
      there are probably more things we could add here.
      
      This will break some source files if Latin-1 characters are being used.
      In most cases this should result in a UTF-8 decoding error.  Later on
      if we want to support more encodings (perhaps with a pragma to specify
      the encoding), I plan to do it by recoding into UTF-8 before parsing.
      
      Internally, there were some pretty big changes:
      
        - FastStrings are now stored in UTF-8
      
        - Z-encoding has been moved right to the back end.  Previously we
          used to Z-encode every identifier on the way in for simplicity,
          and only decode when we needed to show something to the user.
          Instead, we now keep every string in its UTF-8 encoding, and
          Z-encode right before printing it out.  To avoid Z-encoding the
          same string multiple times, the Z-encoding is cached inside the
          FastString the first time it is requested.
      
          This speeds up the compiler - I've measured some definite
          improvement in parsing at least, and I expect compilations overall
          to be faster too.  It also cleans up a lot of cruft from the
          OccName interface.  Z-encoding is nicely hidden inside the
          Outputable instance for Names & OccNames now.
      
        - StringBuffers are UTF-8 too, and are now represented as
          ForeignPtrs.
      
        - I've put together some test cases, not by any means exhaustive,
          but there are some interesting UTF-8 decoding error cases that
          aren't obvious.  Also, take a look at unicode001.hs for a demo.
      9d7da331
  19. 12 Nov, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-11-12 21:41:12 by simonpj] · 87998beb
      simonpj authored
      Better TH -> HsSyn conversion
      
      	Merge to stable (attempt)
      
      This commit monad-ises the TH syntax -> HS syntax conversion.
      This means that error messages can be reported in a more civilised
      way.  It also ensures that the entire structure is converted eagerly.
      That means that any exceptions buried inside it are triggered 
      during conversion, and caught by the exception handler in TcSplice.
      Before, they could be triggered later, and looked like comiler
      crashes.
      87998beb
  20. 14 Oct, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-10-14 11:22:41 by simonpj] · 36436bc6
      simonpj authored
      Add record syntax for GADTs
      	~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      Atrijus Tang wanted to add record syntax for GADTs and existential
      types, so he and I worked on it a bit at ICFP.  This commit is the
      result.  Now you can say
      
       data T a where
        T1 { x :: a }           	 :: T [a]
        T2 { x :: a, y :: Int } 	 :: T [a]
        forall b. Show b =>
       	T3 { naughty :: b, ok :: Int } :: T Int
        T4 :: Eq a => a -> b -> T (a,b)
      
      Here the constructors are declared using record syntax.
      
      Still to come after this commit:
        - User manual documentation
        - More regression tests
        - Some missing cases in the parser (e.g. T3 won't parse)
      Autrijus is going to do these.
      
      
      Here's a quick summary of the rules.  (Atrijus is going to write
      proper documentation shortly.)
      
      Defnition: a 'vanilla' constructor has a type of the form
      	forall a1..an. t1 -> ... -> tm -> T a1 ... an
      No existentials, no context, nothing.  A constructor declared with
      Haskell-98 syntax is vanilla by construction.  A constructor declared
      with GADT-style syntax is vanilla iff its type looks like the above.
      (In the latter case, the order of the type variables does not matter.)
      
      * You can mix record syntax and non-record syntax in a single decl
      
      * All constructors that share a common field 'x' must have the
        same result type (T [a] in the example).
      
      * You can use field names without restriction in record construction
        and record pattern matching.
      
      * Record *update* only works for data types that only have 'vanilla'
        constructors.
      
      * Consider the field 'naughty', which uses a type variable that does
        not appear in the result type ('b' in the example).  You can use the
        field 'naughty' in pattern matching and construction, but NO
        SELECTOR function is generated for 'naughty'.  [An attempt to use
        'naughty' as a selector function will elicit a helpful error
        message.]
      
      * Data types declared in GADT syntax cannot have a context. So this
      is illegal:
      	data (Monad m) => T a where
      		  ....
      
      * Constructors in GADT syntax can have a context (t.g. T3, T4 above)
        and that context is stored in the constructor and made available
        when the constructor is pattern-matched on.  WARNING: not competely
        implemented yet, but that's the plan.
      
      
      
      Implementation notes
      ~~~~~~~~~~~~~~~~~~~~
      - Data constructors (even vanilla ones) no longer share the type
        variables of their parent type constructor.
      
      - HsDecls.ConDecl has changed quite a bit
      
      - TyCons don't record the field labels and type any more (doesn't
        make sense for existential fields)
      
      - GlobalIdDetails records which selectors are 'naughty', and hence
        don't have real code.
      36436bc6
  21. 04 May, 2005 1 commit
  22. 26 Nov, 2004 1 commit
    • simonmar's avatar
      [project @ 2004-11-26 16:19:45 by simonmar] · ef5b4b14
      simonmar authored
      Further integration with the new package story.  GHC now supports
      pretty much everything in the package proposal.
      
        - GHC now works in terms of PackageIds (<pkg>-<version>) rather than
          just package names.  You can still specify package names without
          versions on the command line, as long as the name is unambiguous.
      
        - GHC understands hidden/exposed modules in a package, and will refuse
          to import a hidden module.  Also, the hidden/eposed status of packages
          is taken into account.
      
        - I had to remove the old package syntax from ghc-pkg, backwards
          compatibility isn't really practical.
      
        - All the package.conf.in files have been rewritten in the new syntax,
          and contain a complete list of modules in the package.  I've set all
          the versions to 1.0 for now - please check your package(s) and fix the
          version number & other info appropriately.
      
        - New options:
      
      	-hide-package P    sets the expose flag on package P to False
      	-ignore-package P  unregisters P for this compilation
      
      	For comparison, -package P sets the expose flag on package P
              to True, and also causes P to be linked in eagerly.
      
              -package-name is no longer officially supported.  Unofficially, it's
      	a synonym for -ignore-package, which has more or less the same effect
      	as -package-name used to.
      
      	Note that a package may be hidden and yet still be linked into
      	the program, by virtue of being a dependency of some other package.
      	To completely remove a package from the compiler's internal database,
              use -ignore-package.
      
      	The compiler will complain if any two packages in the
              transitive closure of exposed packages contain the same
              module.
      
      	You *must* use -ignore-package P when compiling modules for
              package P, if package P (or an older version of P) is already
              registered.  The compiler will helpfully complain if you don't.
      	The fptools build system does this.
      
         - Note: the Cabal library won't work yet.  It still thinks GHC uses
           the old package config syntax.
      
      Internal changes/cleanups:
      
         - The ModuleName type has gone away.  Modules are now just (a
           newtype of) FastStrings, and don't contain any package information.
           All the package-related knowledge is in DynFlags, which is passed
           down to where it is needed.
      
         - DynFlags manipulation has been cleaned up somewhat: there are no
           global variables holding DynFlags any more, instead the DynFlags
           are passed around properly.
      
         - There are a few less global variables in GHC.  Lots more are
           scheduled for removal.
      
         - -i is now a dynamic flag, as are all the package-related flags (but
           using them in {-# OPTIONS #-} is Officially Not Recommended).
      
         - make -j now appears to work under fptools/libraries/.  Probably
           wouldn't take much to get it working for a whole build.
      ef5b4b14
  23. 01 Oct, 2004 1 commit
  24. 30 Sep, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-09-30 10:35:15 by simonpj] · 23f40f0e
      simonpj authored
      ------------------------------------
      	Add Generalised Algebraic Data Types
      	------------------------------------
      
      This rather big commit adds support for GADTs.  For example,
      
          data Term a where
       	  Lit :: Int -> Term Int
      	  App :: Term (a->b) -> Term a -> Term b
      	  If  :: Term Bool -> Term a -> Term a
      	  ..etc..
      
          eval :: Term a -> a
          eval (Lit i) = i
          eval (App a b) = eval a (eval b)
          eval (If p q r) | eval p    = eval q
          		    | otherwise = eval r
      
      
      Lots and lots of of related changes throughout the compiler to make
      this fit nicely.
      
      One important change, only loosely related to GADTs, is that skolem
      constants in the typechecker are genuinely immutable and constant, so
      we often get better error messages from the type checker.  See
      TcType.TcTyVarDetails.
      
      There's a new module types/Unify.lhs, which has purely-functional
      unification and matching for Type. This is used both in the typechecker
      (for type refinement of GADTs) and in Core Lint (also for type refinement).
      23f40f0e
  25. 30 Dec, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-12-30 16:29:17 by simonpj] · f714e6b6
      simonpj authored
      ----------------------------
              Re-do kind inference (again)
      	----------------------------
      
         [WARNING: interface file binary representation has
         (as usual) changed slightly; recompile your libraries!]
      
      Inspired by the lambda-cube, for some time GHC has used
      	type Kind = Type
      That is, kinds were represented by the same data type as types.
      
      But GHC also supports unboxed types and unboxed tuples, and these
      complicate the kind system by requiring a sub-kind relationship.
      Notably, an unboxed tuple is acceptable as the *result* of a
      function but not as an *argument*.  So we have the following setup:
      
      		 ?
      		/ \
      	       /   \
      	      ??   (#)
      	     /  \
                  *   #
      
      where	*    [LiftedTypeKind]   means a lifted type
      	#    [UnliftedTypeKind] means an unlifted type
      	(#)  [UbxTupleKind]     means unboxed tuple
      	??   [ArgTypeKind]      is the lub of *,#
      	?    [OpenTypeKind]	means any type at all
      
      In particular:
      
        error :: forall a:?. String -> a
        (->)  :: ?? -> ? -> *
        (\(x::t) -> ...)	Here t::?? (i.e. not unboxed tuple)
      
      All this has beome rather difficult to accommodate with Kind=Type, so this
      commit splits the two.
      
        * Kind is a distinct type, defined in types/Kind.lhs
      
        * IfaceType.IfaceKind disappears: we just re-use Kind.Kind
      
        * TcUnify.unifyKind is a distinct unifier for kinds
      
        * TyCon no longer needs KindCon and SuperKindCon variants
      
        * TcUnify.zapExpectedType takes an expected Kind now, so that
          in TcPat.tcMonoPatBndr we can express that the bound variable
          must have an argTypeKind (??).
      
      The big change is really that kind inference is much more systematic and
      well behaved.  In particular, a kind variable can unify only with a
      "simple kind", which is built from * and (->).  This deals neatly
      with awkward questions about how we can combine sub-kinding with type
      inference.
      
      Lots of small consequential changes, especially to the kind-checking
      plumbing in TcTyClsDecls.  (We played a bit fast and loose before, and
      now we have to be more honest, in particular about how kind inference
      works for type synonyms.  They can have kinds like (* -> #), so
      
      This cures two long-standing SourceForge bugs
      
      * 753777 (tcfail115.hs), which used erroneously to pass,
        but crashed in the code generator
            type T a = Int -> (# Int, Int #)
            f :: T a -> T a
            f t = \x -> case t x of r -> r
      
      * 753780 (tc167.hs), which used erroneously to fail
            f :: (->) Int# Int#
      
      
      Still, the result is not entirely satisfactory.  In particular
      
      * The error message from tcfail115 is pretty obscure
      
      * SourceForge bug 807249 (Instance match failure on openTypeKind)
        is not fixed.  Alas.
      f714e6b6
  26. 10 Dec, 2003 1 commit
    • 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
  27. 21 Oct, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-10-21 12:54:17 by simonpj] · 1bade0c9
      simonpj authored
      1. A tiresome change to HsType, to keep a record of whether or not
         the HsForAll was originally explicitly-quantified.  This is
         solely so that the type checker can print out messages that
         show the source code the programmer wrote.  Tiresome but
         easy.
      
      2. Improve reporting of kind errors.
      1bade0c9
  28. 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
  29. 19 Aug, 2003 1 commit
    • krc's avatar
      [project @ 2003-08-19 22:04:54 by krc] · a465e8bd
      krc authored
      Added correct parsing of external calls. External calls are assumed to be
      static C calls, but this assumption should always hold since compiling to
      External Core will fail for programs that contain any other kind of
      external call.
      
      Added correct parsing of the null-pointer literal (0::GHCziPrim.Addrzh) --
      this caused an "unknown integer literal type" error before.
      a465e8bd
  30. 11 Jul, 2003 1 commit
  31. 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
  32. 11 Mar, 2003 1 commit
  33. 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
  34. 11 Dec, 2002 1 commit
  35. 10 Dec, 2002 1 commit
  36. 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
  37. 27 May, 2002 1 commit
  38. 21 May, 2002 1 commit
  39. 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
  40. 11 Apr, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-04-11 12:03:29 by simonpj] · a7b95beb
      simonpj authored
      -------------------
      	Mainly derived Read
      	-------------------
      
      This commit is a tangle of several things that somehow got wound up
      together, I'm afraid.
      
      
      The main course
      ~~~~~~~~~~~~~~~
      Replace the derived-Read machinery with Koen's cunning new parser
      combinator library.   The result should be
      	* much smaller code sizes from derived Read
      	* faster execution of derived Read
      
      WARNING: I have not thoroughly tested this stuff; I'd be glad if you did!
      	 All the hard work is done, but there may be a few nits.
      
      The Read class gets two new methods, not exposed
      in the H98 inteface of course:
        class Read a where
          readsPrec    :: Int -> ReadS a
          readList     :: ReadS [a]
          readPrec     :: ReadPrec a		-- NEW
          readListPrec :: ReadPrec [a]	-- NEW
      
      There are the following new libraries:
      
        Text.ParserCombinators.ReadP		Koens combinator parser
        Text.ParserCombinators.ReadPrec	Ditto, but with precedences
      
        Text.Read.Lex				An emasculated lexical analyser
      					that provides the functionality
      					of H98 'lex'
      
      TcGenDeriv is changed to generate code that uses the new libraries.
      The built-in instances of Read (List, Maybe, tuples, etc) use the new
      libraries.
      
      
      Other stuff
      ~~~~~~~~~~~
      1. Some fixes the the plumbing of external-core generation. Sigbjorn
      did most of the work earlier, but this commit completes the renaming and
      typechecking plumbing.
      
      2. Runtime error-generation functions, such as GHC.Err.recSelErr,
      GHC.Err.recUpdErr, etc, now take an Addr#, pointing to a UTF8-encoded
      C string, instead of a Haskell string.  This makes the *calls* to these
      functions easier to generate, and smaller too, which is a good thing.
      
      In particular, it means that MkId.mkRecordSelectorId doesn't need to
      be passed "unpackCStringId", which was GRUESOME; and that in turn means
      that tcTypeAndClassDecls doesn't need to be passed unf_env, which is
      a very worthwhile cleanup.   Win/win situation.
      
      3.  GHC now faithfully translates do-notation using ">>" for statements
      with no binding, just as the report says.  While I was there I tidied
      up HsDo to take a list of Ids instead of 3 (but now 4) separate Ids.
      Saves a bit of code here and there.  Also introduced Inst.newMethodFromName
      to package a common idiom.
      a7b95beb