1. 08 Apr, 2005 1 commit
  2. 31 Mar, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-03-31 15:16:53 by simonmar] · c1909a1b
      simonmar authored
      More hacking on the GHC API to get it into shape for VS
      
       - load now takes a LoadHowMuch argument, which is either
      	LoadAllTargets
      	LoadUpTo Module
      	LoadDependenciesOf Module
         which should be self-explanatory.  LoadDependenciesOf might go
         away in the future, it's necessary at the moment because it is
         used in the implementation of:
      
       - checkModule :: Session -> Module -> MessageHandler -> IO CheckResult
      
         which is currently the only way to get at the parsed & typechecked
         abstract syntax for a module.
      c1909a1b
  3. 30 Mar, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-03-30 16:24:04 by simonmar] · 6720aae4
      simonmar authored
      Add support for partial reloads in the GHC API.
      
      This is mainly for VS: when editing a file you don't want to
      continually reload the entire project whenever the current file
      changes, you want to reload up to and including the current file only.
      However, you also want to retain any other modules in the session that
      are still stable.
      
      I added a variant of :reload in GHCi to test this.  You can say
      ':reload M' to reload up to module M only.  This will bring M up to
      date, and throw away any invalidated modules from the session.
      6720aae4
  4. 22 Mar, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-03-22 17:13:12 by simonmar] · 069370a5
      simonmar authored
      A start on the GHC API:
      
      Flesh out the GHC module so that it can replace CompManager.  Now, the
      clients that used CompManager consume the GHC API instead (namely
      Main, DriverMkDepend, and InteractiveUI).  Main is significantly
      cleaner as a result.
      
      The interface needs more work: in particular, getInfo returns results
      in the form of IfaceDecls but we want to use full HsSyn and
      Id/DataCon/Class across the boundary instead.
      
      The interfaces for inspecting loaded modules are not yet implemented.
      069370a5
  5. 18 Mar, 2005 2 commits
    • simonpj's avatar
      [project @ 2005-03-18 17:16:00 by simonpj] · d5b3e9b5
      simonpj authored
      Fix stage-2 build
      d5b3e9b5
    • simonmar's avatar
      [project @ 2005-03-18 13:37:27 by simonmar] · d1c1b7d0
      simonmar authored
      Flags cleanup.
      
      Basically the purpose of this commit is to move more of the compiler's
      global state into DynFlags, which is moving in the direction we need
      to go for the GHC API which can have multiple active sessions
      supported by a single GHC instance.
      
      Before:
      
      $ grep 'global_var' */*hs | wc -l
           78
      
      After:
      
      $ grep 'global_var' */*hs | wc -l
           27
      
      Well, it's an improvement.  Most of what's left won't really affect
      our ability to host multiple sessions.
      
      Lots of static flags have become dynamic flags (yay!).  Notably lots
      of flags that we used to think of as "driver" flags, like -I and -L,
      are now dynamic.  The most notable static flags left behind are the
      "way" flags, eg. -prof.  It would be nice to fix this, but it isn't
      urgent.
      
      On the way, lots of cleanup has happened.  Everything related to
      static and dynamic flags lives in StaticFlags and DynFlags
      respectively, and they share a common command-line parser library in
      CmdLineParser.  The flags related to modes (--makde, --interactive
      etc.) are now private to the front end: in fact private to Main
      itself, for now.
      d1c1b7d0
  6. 08 Mar, 2005 1 commit
  7. 28 Feb, 2005 1 commit
  8. 25 Feb, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-02-25 13:06:31 by simonpj] · 8e67f550
      simonpj authored
      ---------------------------------------------
      Type signatures are no longer instantiated with skolem constants
      	---------------------------------------------
      
      	Merge to STABLE
      
      Consider
      
        p :: a
        q :: b
        (p,q,r) = (r,r,p)
      
      Here, 'a' and 'b' end up being the same, because they are both bound
      to the type for 'r', which is just a meta type variable.  So 'a' and 'b'
      can't be skolems.
      
      Sigh.  This commit goes back to an earlier way of doing things, by
      arranging that type signatures get instantiated with *meta* type
      variables; then at the end we must check that they have not been
      unified with types, nor with each other.
      
      This is a real bore.  I had to do quite a bit of related fiddling around
      to make error messages come out right.  Improved one or two.
      
      Also a small unrelated fix to make
      	:i (:+)
      print with parens in ghci.  Sorry this got mixed up in the same commit.
      8e67f550
  9. 23 Feb, 2005 2 commits
  10. 15 Feb, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-02-15 12:15:25 by simonmar] · bb764eda
      simonmar authored
      ghc -e 'System.Exit.exitWith (System.Exit.ExitFailure 99)'
      
      should just exit 99, rather than printing out the exception.  Also
      while I'm here, make all other exceptions cause 'ghc -e' to exit(1),
      which is probably what we want.
      bb764eda
  11. 04 Feb, 2005 1 commit
  12. 28 Jan, 2005 2 commits
    • simonpj's avatar
      [project @ 2005-01-28 17:44:55 by simonpj] · c51fdf44
      simonpj authored
      Arrange that when seeking instance decls in GHCi, in response
      to a :info command, we only print ones whose types are in scope
      unqualified.  This eliminates an alarmingly long list when
      simply typing ':info Show', say.
      
      On the way, I reorganised a bit.  GHCi printing happens by
      converting a TyThing to an IfaceDecl, and printing that.
      I now arrange to generate unqualifed IfaceExtNames directly
      during this conversion, based on what is in scope.  Previously
      it was done during the pretty-printing part via the UserStyle.
      But this is nicer.
      c51fdf44
    • simonmar's avatar
      [project @ 2005-01-28 12:55:17 by simonmar] · 153b9cb9
      simonmar authored
      Rationalise the BUILD,HOST,TARGET defines.
      
      Recall that:
      
        - build is the platform we're building on
        - host is the platform we're running on
        - target is the platform we're generating code for
      
      The change is that now we take these definitions as applying from the
      point of view of the particular source code being built, rather than
      the point of view of the whole build tree.
      
      For example, in RTS and library code, we were previously testing the
      TARGET platform.  But under the new rule, the platform on which this
      code is going to run is the HOST platform.  TARGET only makes sense in
      the compiler sources.
      
      In practical terms, this means that the values of BUILD, HOST & TARGET
      may vary depending on which part of the build tree we are in.
      
      Actual changes:
      
       - new file: includes/ghcplatform.h contains platform defines for
         the RTS and library code.
      
       - new file: includes/ghcautoconf.h contains the autoconf settings
         only (HAVE_BLAH).  This is so that we can get hold of these
         settings independently of the platform defines when necessary
         (eg. in GHC).
      
       - ghcconfig.h now #includes both ghcplatform.h and ghcautoconf.h.
      
       - MachRegs.h, which is included into both the compiler and the RTS,
         now has to cope with the fact that it might need to test either
         _TARGET_ or _HOST_ depending on the context.
      
       - the compiler's Makefile now generates
           stage{1,2,3}/ghc_boot_platform.h
         which contains platform defines for the compiler.  These differ
         depending on the stage, of course: in stage2, the HOST is the
         TARGET of stage1.  This was wrong before.
      
       - The compiler doesn't get platform info from Config.hs any more.
         Previously it did (sometimes), but unless we want to generate
         a new Config.hs for each stage we can't do this.
      
       - GHC now helpfully defines *_{BUILD,HOST}_{OS,ARCH} automatically
         in CPP'd Haskell source.
      
       - ghcplatform.h defines *_TARGET_* for backwards compatibility
         (ghcplatform.h is included by ghcconfig.h, which is included by
         config.h, so code which still #includes config.h will get the TARGET
         settings as before).
      
       - The Users's Guide is updated to mention *_HOST_* rather than
         *_TARGET_*.
      
       - coding-style.html in the commentary now contains a section on
         platform defines.  There are further doc updates to come.
      
      Thanks to Wolfgang Thaller for pointing me in the right direction.
      153b9cb9
  13. 26 Jan, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-01-26 12:58:09 by simonmar] · 66797dc0
      simonmar authored
      fileLoop: catch InvalidArgument and behave as for EOF (i.e. terminate
      the session).  This means that the user can close stdin to end a GHCi
      session, but it also means that the tests that run programs which use
      getContents inside GHCi won't crash because stdin has been closed.
      66797dc0
  14. 18 Jan, 2005 1 commit
    • simonpj's avatar
      [project @ 2005-01-18 12:18:11 by simonpj] · ac80e0de
      simonpj authored
      ------------------------
          Reorganisation of hi-boot files
        	------------------------
      
      The main point of this commit is to arrange that in the Compilation
      Manager's dependendency graph, hi-boot files are proper nodes. This
      is important to make sure that we compile everything in the right
      order.  It's a step towards hs-boot files.
      
      * The fundamental change is that CompManager.ModSummary has a new
        field, ms_boot :: IsBootInterface
      
        I also tided up CompManager a bit.  No change to the Basic Plan.
      
        ModSummary is now exported abstractly from CompManager (was concrete)
      
      * Hi-boot files now have import declarations.  The idea is they are
        compulsory, so that the dependency analyser can find them
      
      * I changed an invariant: the Compilation Manager used to ensure that
        hscMain was given a HomePackageTable only for the modules 'below' the
        one being compiled.  This was really only important for instances and
        rules, and it was a bit inconvenient.  So I moved the filter to the
        compiler itself: see HscTypes.hptInstances and hptRules.
      
      * Module Packages.hs now defines
          data PackageIdH
          = HomePackage 		-- The "home" package is the package
       				-- curently being compiled
          | ExtPackage PackageId	-- An "external" package is any other package
      
         It was just a Maybe type before, so this makes it a bit clearer.
      
      * I tried to add a bit better location info to the IfM monad, so that
        errors in interfaces come with a slightly more helpful error message.
        See the if_loc field in TcRnTypes --- and follow-on consequences
      
      * Changed Either to Maybes.MaybeErr in a couple of places (more perspicuous)
      ac80e0de
  15. 12 Jan, 2005 2 commits
  16. 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
  17. 12 Nov, 2004 1 commit
  18. 13 Oct, 2004 1 commit
  19. 11 Oct, 2004 1 commit
  20. 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
  21. 20 Aug, 2004 1 commit
    • simonmar's avatar
      [project @ 2004-08-20 15:02:40 by simonmar] · fcbc4b62
      simonmar authored
      Hack to work around bug on Windows reported by Levent Erkok
      <levent.erkok@intel.com>:
      
      Prelude> let x=x in x
      *** Exception: <<loop>>
      Prelude> 3
      Fail: thread blocked indefinitely
      
      Details in the comment.
      
      MERGE TO STABLE
      fcbc4b62
  22. 16 Aug, 2004 1 commit
    • simonpj's avatar
      [project @ 2004-08-16 09:53:47 by simonpj] · 4e325538
      simonpj authored
      -------------------------------
      	Add instance information to :i
       	Get rid of the DeclPool
      	-------------------------------
      
      
      1.  Add instance information to :info command.  GHCi now prints out
          which instances a type or class belongs to, when you use :i
      
      2.  Tidy up printing of unqualified names in user output.
          Previously Outputable.PrintUnqualified was
      	type PrintUnqualified = Name -> Bool
          but it's now
      	type PrintUnqualified = ModuleName -> OccName -> Bool
          This turns out to be tidier even for Names, and it's now also usable
          when printing IfaceSyn stuff in GHCi, eliminating a grevious hack.
      
      3.  On the way to doing this, Simon M had the great idea that we could
          get rid of the DeclPool holding pen, which held declarations read from
          interface files but not yet type-checked.   We do this by eagerly
          populating the TypeEnv with thunks what, when poked, do the type
          checking.   This is just a logical continuation of lazy import
          mechanism we've now had for some while.
      
      The InstPool and RulePool still exist, but I plan to get rid of them in
      the same way.  The new scheme does mean that more rules get sucked in than
      before, because previously the TypeEnv was used to mean "this thing was needed"
      and hence to control which rules were sucked in.  But now the TypeEnv is
      populated more eagerly => more rules get sucked in.  However this problem
      will go away when I get rid of the Inst and Rule pools.
      
      I should have kept these changes separate, but I didn't.  Change (1)
      affects mainly
      	TcRnDriver, HscMain, CompMan, InteractiveUI
      whereas change (3) is more wide ranging.
      4e325538
  23. 13 Aug, 2004 1 commit
  24. 12 Aug, 2004 2 commits
  25. 09 Aug, 2004 1 commit
  26. 30 Jul, 2004 1 commit
  27. 21 Jul, 2004 2 commits
    • simonpj's avatar
      [project @ 2004-07-21 10:07:29 by simonpj] · 1004a5a3
      simonpj authored
      Add location information to :i command
      1004a5a3
    • simonpj's avatar
      [project @ 2004-07-21 09:25:42 by simonpj] · 10ab808b
      simonpj authored
      -------------------------------
             Sort out the :i command for GHCi
      	-------------------------------
      
      The :info command has been broken in the HEAD for some time, since the new IfaceSyn
      story.  This commit sorts it out, and makes it nicer than before. For example, when
      you :i a record selector, you get a cut-down data type declaration, so you can see
      the context.
      10ab808b
  28. 27 May, 2004 1 commit
  29. 05 Apr, 2004 2 commits
  30. 01 Feb, 2004 1 commit
  31. 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
  32. 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
  33. 23 Sep, 2003 1 commit
    • simonmar's avatar
      [project @ 2003-09-23 14:32:57 by simonmar] · abbc5a0b
      simonmar authored
      - Convert many of the optimisation options into dynamic options (that is,
        they can be mentioned in {-# OPTIONS #-} pragmas).
      
      - Add a new way to specify constructor-field unboxing on a selective
        basis.  To tell the compiler to unbox a constructor field, do this:
      
            data T = T !!Int
      
        and GHC will store that field unboxed if possible.  If it isn't possible
        (say, because the field has a sum type) then the annotation is ignored.
      
        The -funbox-strict-fields flag is now a dynamic flag, and has the same
        effect as replacing all the '!' annotations with '!!'.
      abbc5a0b