1. 30 Oct, 2003 1 commit
  2. 23 Oct, 2003 1 commit
  3. 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
  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. 15 Aug, 2003 1 commit
  6. 24 Jun, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-06-24 07:58:18 by simonpj] · 16e4ce4c
      simonpj authored
      ----------------------------------------------
      	Add support for Ross Paterson's arrow notation
      	----------------------------------------------
      
      Ross Paterson's ICFP'01 paper described syntax to support John Hughes's
      "arrows", rather as do-notation supports monads.  Except that do-notation is
      relatively modest -- you can write monads by hand without much trouble --
      whereas arrow-notation is more-or-less essential for writing arrow programs.
      It desugars to a massive pile of tuple construction and selection!
      
      For some time, Ross has had a pre-processor for arrow notation, but the
      resulting type error messages (reported in terms of the desugared code)
      are impenetrable.  This commit integrates the syntax into GHC.  The
      type error messages almost certainly still require tuning, but they should
      be better than with the pre-processor.
      
      Main syntactic changes (enabled with -farrows)
      
         exp ::= ... | proc pat -> cmd
      
         cmd ::= exp1 -<  exp2   |  exp1 >-  exp2
      	|  exp1 -<< exp2   |  exp1 >>- exp2
      	| \ pat1 .. patn -> cmd
      	| let decls in cmd
      	| if exp then cmd1 else cmd2
      	| do { cstmt1 .. cstmtn ; cmd }
      	| (| exp |) cmd1 .. cmdn
      	| cmd1 qop cmd2
      	| case exp of { calts }
      
         cstmt :: = let decls
      	 |   pat <- cmd
      	 |   rec { cstmt1 .. cstmtn }
      	 |   cmd
      
      New keywords and symbols:
      	proc rec
      	-<   >-   -<<   >>-
      	(|  |)
      
      The do-notation in cmds was not described in Ross's ICFP'01 paper; instead
      it's in his chapter in The Fun of Programming (Plagrave 2003).
      
      The four arrow-tail forms (-<) etc cover
        (a) which order the pices come in (-<  vs  >-), and
        (b) whether the locally bound variables can be used in the
      		arrow part (-<  vs  -<<) .
      In previous presentations, the higher-order-ness (b) was inferred,
      but it makes a big difference to the typing required so it seems more
      consistent to be explicit.
      
      The 'rec' form is also available in do-notation:
        * you can use 'rec' in an ordinary do, with the obvious meaning
        * using 'mdo' just says "infer the minimal recs"
      
      
      Still to do
      ~~~~~~~~~~~
      Top priority is the user manual.
      
      The implementation still lacks an implementation of
      the case form of cmd.
      
      
      Implementation notes
      ~~~~~~~~~~~~~~~~~~~~
      Cmds are parsed, and indeed renamed, as expressions.  The type checker
      distinguishes the two.
      16e4ce4c
  7. 08 Jun, 2003 1 commit
  8. 06 Jun, 2003 1 commit
  9. 21 May, 2003 2 commits
    • igloo's avatar
      [project @ 2003-05-21 18:07:13 by igloo] · 9b5fb22b
      igloo authored
      The Great Renaming. I hope I've kept everything in sync - and all the tests
      pass. Now datatypes follow the
      
      data Foo = <a kind of Foo>Foo
               | <another kind of Foo>Foo
      
      convention and the smart constructors can be uniformly created by
      lowercasing the first letter of the constructor.
      9b5fb22b
    • igloo's avatar
      [project @ 2003-05-21 02:58:39 by igloo] · a011a71c
      igloo authored
      Added support for newtypes to TH and altered a test for them.
      a011a71c
  10. 19 May, 2003 1 commit
    • simonpj's avatar
      [project @ 2003-05-19 15:10:40 by simonpj] · 20555469
      simonpj authored
      --------------------------
      	Minor Template Haskell bug
      	--------------------------
      
      This bug meant that spliced-in class declarations yielded a 'op not in scope',
      where op was the class operation.  Thanks to Andre Pang for spotting this.
      
      Some consequential tidying up in parsing too.
      20555469
  11. 04 May, 2003 1 commit
  12. 25 Apr, 2003 1 commit
  13. 22 Apr, 2003 1 commit
    • igloo's avatar
      [project @ 2003-04-22 20:39:59 by igloo] · c21fbf92
      igloo authored
      Order declarations in reifications in order of source line number.
      The bugs still there but it bites less often now...
      
      Also remove the type parameterisation and do some type renaming as
      discussed on the template-haskell list.
      c21fbf92
  14. 16 Mar, 2003 1 commit
  15. 18 Feb, 2003 1 commit
    • igloo's avatar
      [project @ 2003-02-18 16:23:35 by igloo] · cdb01ba2
      igloo authored
      Support strictness annotations on data declarations and support the record
      and infix constructors. Also tweaked the pretty printer a bit.
      cdb01ba2
  16. 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
  17. 06 Feb, 2003 2 commits
    • simonpj's avatar
      [project @ 2003-02-06 17:37:50 by simonpj] · 406a82d9
      simonpj authored
      Deal with TForall in cvtType
      406a82d9
    • simonpj's avatar
      [project @ 2003-02-06 17:15:50 by simonpj] · 70e9ee75
      simonpj authored
      -------------------------------------
        Fix parsing of floating-point constants in External Core
      	-------------------------------------
      
      This fix accidentally made it into the previous (unrelated) commit,
      so it's really the *previous* change to LexCore you should look
      at.
      
      The fix updates LexCore so that it can parse literals in scientific
      notation (e.g. 4.3e-3)
      70e9ee75
  18. 18 Dec, 2002 2 commits
  19. 11 Dec, 2002 2 commits
  20. 10 Dec, 2002 2 commits
  21. 21 Nov, 2002 2 commits
  22. 20 Nov, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-11-20 15:43:37 by simonpj] · f2e26fc5
      simonpj authored
      Three Template Haskell improvements
      
      a) Add type synonyms to THSyntax (and DsMeta, Convert)
      
      b) Make Q into a newtype instead of a type synonym
      
      c) Eliminate tiresome and error prone argument to DsMeta.wrapGenSyms
         and similarly addTyVarBinds
      f2e26fc5
  23. 08 Nov, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-11-08 09:01:06 by simonpj] · 73641e01
      simonpj authored
      ------------------
        	   More TH stuff (thanks to Ian L)
      		------------------
      
      * Make TH Literals have an Integer not an Int
      * Desguar TH 'foreign import' a bit better
      * Minor documentation changes
      73641e01
  24. 06 Nov, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-11-06 13:10:46 by simonpj] · e26dd9a9
      simonpj authored
      ------------------
      		Template Haskell stuff
      		------------------
      
      a) Pretty printer for TH (thanks to Ian Lynagh)
      
      b) A declaration quote has type Q [Dec], not [Q Dec] as in
         the paper
      
      c) Foreign imports are part of THSyntax, and can be spliced in
      e26dd9a9
  25. 31 Oct, 2002 1 commit
  26. 30 Oct, 2002 2 commits
  27. 09 Oct, 2002 1 commit
    • simonpj's avatar
      [project @ 2002-10-09 15:03:48 by simonpj] · 8c1b6bd7
      simonpj authored
      -----------------------------------
      	Lots more Template Haskell stuff
      	-----------------------------------
      
      At last!  Top-level declaration splices work!
      Syntax is
      
      	$(f x)
      
      not "splice (f x)" as in the paper.
      
      Lots jiggling around, particularly with the top-level plumbining.
      Note the new data type HsDecls.HsGroup.
      8c1b6bd7
  28. 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
  29. 13 Sep, 2002 2 commits
    • simonpj's avatar
      [project @ 2002-09-13 16:06:28 by simonpj] · 99b85ea1
      simonpj authored
      wibbles
      99b85ea1
    • 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