Implement initial-state (emptyTy :: Ty) functions.

Names of mpz routines in GMP 3 now have a "__g" prefix (untested, but
should fix the NCG).

- move readMVar and swapMVar from PrelConc to concurrent

- add the following exception-safe MVar operations:

	withMVar    :: MVar a -> (a -> IO b) -> IO b
	modifyMVar  :: MVar a -> (a -> IO (a,b)) -> IO b
	modifyMVar_ :: MVar a -> (a -> IO a) -> IO ()

- re-implement readMVar and swapMVar in an exception-safe way.

- re-implement the Chan operations using withMVar et al.

Add tc107

New modules for GHCI.

A few more internal consistency fixes seen when making new modules in
ghc/compiler/ghci.

Changed *do* to <Emphasis>do</Emphasis>

Internal consistency wibble: @LinkState@ --> @PLS@.

Another wibble

wibbles

Fill in details about how CM works.

Simon's log file; I don't want to lose this!

Wibbles

------------------------------------
	   Mainly PredTypes (28 Sept 00)
	------------------------------------

Three things in this commit:

	1.  Main thing: tidy up PredTypes
	2.  Move all Keys into PrelNames
	3.  Check for unboxed tuples in function args

1. Tidy up PredTypes
~~~~~~~~~~~~~~~~~~~~
The main thing in this commit is to modify the representation of Types
so that they are a (much) better for the qualified-type world.  This
should simplify Jeff's life as he proceeds with implicit parameters
and functional dependencies.  In particular, PredType, introduced by
Jeff, is now blessed and dignified with a place in TypeRep.lhs:

	data PredType  = Class  Class [Type]
		       | IParam Name  Type

Consider these examples:
	f :: (Eq a) => a -> Int
	g :: (?x :: Int -> Int) => a -> Int
	h :: (r\l) => {r} => {l::Int | r}

Here the "Eq a" and "?x :: Int -> Int" and "r\l" are all called
*predicates*, and are represented by a PredType.  (We don't support
TREX records yet, but the setup is designed to expand to allow them.)

In addition, Type gains an extra constructor:

	data Type = .... | PredTy PredType

so that PredType is injected directly into Type.  So the type
	p => t
is represented by
	PredType p `FunTy` t

I have deleted the hackish IPNote stuff; predicates are dealt with entirely
through PredTys, not through NoteTy at all.


2.  Move Keys into PrelNames
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is just a housekeeping operation. I've moved all the pre-assigned Uniques
(aka Keys) from Unique.lhs into PrelNames.lhs.  I've also moved knowKeyRdrNames
from PrelInfo down into PrelNames.  This localises in PrelNames lots of stuff
about predefined names.  Previously one had to alter three files to add one,
now only one.

3.  Unboxed tuples
~~~~~~~~~~~~~~~~~~
Add a static check for unboxed tuple arguments.  E.g.
	data T = T (# Int, Int #)
is illegal

Define relationship between what CM implements and the HEP interface.
Start on saying how CM behaves.

Further cleanups, and add defs for ModDetails, ModIFace and Ifaces.

Big reorganisation, to put CM, compile, link into seperate sections.
Ongoing.

Remove Addr2IntegerOp reference

* Remove all traces of addr2Integer.  Big integer literals are now
  done by multiplying up small integers.

* As a result, we can remove PrelNum.hi-boot altogether.

* Correct the default method for (==) in PrelBase.  (It simply
  returned True, which seems bogus to me!)

* Add a type signature for PrelBase.mapFB

Rearrange the Linker section a bit, in line with upcoming rearrangement
of Compiler and CM sections.

Document the new behaviour of -fno-implicit-prelude.

(I havn't checked that the new document builds right because
my build tree doesn't seem to build documentation.  Reuben,
could you check, please.)

linker spec updates

Add the GHCi design document to CVS.

Added missing !

Suck in plus/timesInteger for integer literals

Fix slightly bogus error message

--------------------------------------------------
	Tidying up HsLit, and making it possible to define
		your own numeric library

		Simon PJ 22 Sept 00
	--------------------------------------------------

I forgot to commit changes to the libraries!  The main thing
is to define monomorphic plusInteger, timesInteger etc, in PrelNum.

Fix a couple of problems with the recompilation avoidance stuff.

arguments of StgLam should be bndrs, not Id.

INLINE is_ctype, otherwise charType gets inlined in the RHS by virtue
of only being used once, and we lose the opportunity to inline is_ctype.

remove unused imports

Make flushFile and flushBuffer consistent.  This code looked wrong
before, and it looks more correct now.

I can't see any need for flushFile at all.

flushBuffer still doesn't do the lseek thing that flushReadBuffer
does.

Don't blindly flush the buffer just because it is writeable.  It might
be a RW handle with a read buffer.

Forgot to remove HsBasic and add HsLit

--------------------------------------------------
	Tidying up HsLit, and making it possible to define
		your own numeric library

		Simon PJ 22 Sept 00
	--------------------------------------------------

** NOTE: I did these changes on the aeroplane.  They should compile,
	 and the Prelude still compiles OK, but it's entirely 
	 possible that I've broken something

The original reason for this many-file but rather shallow
commit is that it's impossible in Haskell to write your own
numeric library.  Why?  Because when you say '1' you get 
(Prelude.fromInteger 1), regardless of what you hide from the
Prelude, or import from other libraries you have written.  So the
idea is to extend the -fno-implicit-prelude flag so that 
in addition to no importing the Prelude, you can rebind 
	fromInteger	-- Applied to literal constants
	fromRational	-- Ditto
	negate		-- Invoked by the syntax (-x)
	the (-) used when desugaring n+k patterns

After toying with other designs, I eventually settled on a simple,
crude one: rather than adding a new flag, I just extended the
semantics of -fno-implicit-prelude so that uses of fromInteger,
fromRational and negate are all bound to "whatever is in scope" 
rather than "the fixed Prelude functions".  So if you say

	{-# OPTIONS -fno-implicit-prelude #-}
	module M where
 	import MyPrelude( fromInteger )

	x = 3

the literal 3 will use whatever (unqualified) "fromInteger" is in scope,
in this case the one gotten from MyPrelude.


On the way, though, I studied how HsLit worked, and did a substantial tidy
up, deleting quite a lot of code along the way.  In particular.

* HsBasic.lhs is renamed HsLit.lhs.  It defines the HsLit type.

* There are now two HsLit types, both defined in HsLit.
	HsLit for non-overloaded literals (like 'x')
	HsOverLit for overloaded literals (like 1 and 2.3)

* HsOverLit completely replaces Inst.OverloadedLit, which disappears.
  An HsExpr can now be an HsOverLit as well as an HsLit.

* HsOverLit carries the Name of the fromInteger/fromRational operation,
  so that the renamer can help with looking up the unqualified name 
  when -fno-implicit-prelude is on.  Ditto the HsExpr for negation.
  It's all very tidy now.

* RdrHsSyn contains the stuff that handles -fno-implicit-prelude
  (see esp RdrHsSyn.prelQual).  RdrHsSyn also contains all the "smart constructors"
  used by the parser when building HsSyn.  See for example RdrHsSyn.mkNegApp
  (previously the renamer (!) did the business of turning (- 3#) into -3#).

* I tidied up the handling of "special ids" in the parser.  There's much
  less duplication now.

* Move Sven's Horner stuff to the desugarer, where it belongs.  
  There's now a nice function DsUtils.mkIntegerLit which brings together
  related code from no fewer than three separate places into one single
  place.  Nice!

* A nice tidy-up in MatchLit.partitionEqnsByLit became possible.

* Desugaring of HsLits is now much tidier (DsExpr.dsLit)

* Some stuff to do with RdrNames is moved from ParseUtil.lhs to RdrHsSyn.lhs,
  which is where it really belongs.

* I also removed 
	many unnecessary imports from modules 
	quite a bit of dead code
  in divers places

msg1

rename blockAsyncExceptions and unblockAsyncExceptions to block and
unblock repectively, to match all the literature.  DEPRECATE the old
names.

---------------------------------------
	Simon's tuning changes: early Sept 2000
	---------------------------------------

Library changes
~~~~~~~~~~~~~~~
* Eta expand PrelShow.showLitChar.  It's impossible to compile this well,
  and it makes a big difference to some programs (e.g. gen_regexps)

* Make PrelList.concat into a good producer (in the foldr/build sense)


Flag changes
~~~~~~~~~~~~
* Add -ddump-hi-diffs to print out changes in interface files.  Useful
  when watching what the compiler is doing

* Add -funfolding-update-in-place to enable the experimental optimisation
  that makes the inliner a bit keener to inline if it's in the RHS of
  a thunk that might be updated in place.  Sometimes this is a bad idea
  (one example is in spectral/sphere; see notes in nofib/Simon-nofib-notes)


Tuning things
~~~~~~~~~~~~~
* Fix a bug in SetLevels.lvlMFE.  (change ctxt_lvl to dest_level)
  I don't think this has any performance effect, but it saves making
  a redundant let-binding that is later eliminated.

* Desugar.dsProgram and DsForeign
  Glom together all the bindings into a single Rec.  Previously the
  bindings generated by 'foreign' declarations were not glommed together, but
  this led to an infelicity (i.e. poorer code than necessary) in the modules
  that actually declare Float and Double (explained a bit more in Desugar.dsProgram)

* OccurAnal.shortMeOut and IdInfo.shortableIdInfo
  Don't do the occurrence analyser's shorting out stuff for things which
  have rules.  Comments near IdInfo.shortableIdInfo.
  This is deeply boring, and mainly to do with making rules work well.
  Maybe rules should have phases attached too....

* CprAnalyse.addIdCprInfo
  Be a bit more willing to add CPR information to thunks;
  in particular, if the strictness analyser has just discovered that this
  is a strict let, then the let-to-case transform will happen, and CPR is fine.
  This made a big difference to PrelBase.modInt, which had something like
	modInt = \ x -> let r = ... -> I# v in
			...body strict in r...
  r's RHS isn't a value yet; but modInt returns r in various branches, so
  if r doesn't have the CPR property then neither does modInt

* MkId.mkDataConWrapId
  Arrange that vanilla constructors, like (:) and I#, get unfoldings that are
  just a simple variable $w:, $wI#.  This ensures they'll be inlined even into
  rules etc, which makes matching a bit more reliable.  The downside is that in
  situations like (map (:) xs), we'll end up with (map (\y ys. $w: y ys) xs.
  Which is tiresome but it doesn't happen much.

* SaAbsInt.findStrictness
  Deal with the case where a thing with no arguments is bottom.  This is Good.
  E.g.   module M where { foo = error "help" }
  Suppose we have in another module
	case M.foo of ...
  Then we'd like to do the case-of-error transform, without inlining foo.


Tidying up things
~~~~~~~~~~~~~~~~~
* Reorganised Simplify.completeBinding (again).

* Removed the is_bot field in CoreUnfolding (is_cheap is true if is_bot is!)
  This is just a tidy up

* HsDecls and others
  Remove the NewCon constructor from ConDecl.  It just added code, and nothing else.
  And it led to a bug in MkIface, which though that a newtype decl was always changing!

* IdInfo and many others
  Remove all vestiges of UpdateInfo (hasn't been used for years)

Improve the kind-inference test

don't forget to bail out when "compilation IS NOT required"