Adding a new experimental partial evalutator

GF.Compile.Compute.ConcreteNew + two new modules contain a new
partial evaluator intended to solve some performance problems with the old
partial evalutator in GF.Compile.Compute.ConcreteLazy. It has been around for
a while, but is now complete enough to compile the RGL and the Phrasebook.

The old partial evaluator is still used by default. The new one can be activated
in two ways:

  - by using the command line option -new-comp when invoking GF.
  - by using cabal configure -fnew-comp to make -new-comp the default. In this
    case you can also use the command line option -old-comp to revert to the old
    partial evaluator.

In the GF shell, the cc command uses the old evaluator regardless of -new-comp
for now, but you can use "cc -new ..." to invoke the new evaluator.

With -new-comp, computations happen in GF.Compile.GeneratePMCFG instead of
GF.Compile.Optimize. This is implemented by testing the flag optNewComp in
both modules, to omit calls to the old partial evaluator from GF.Compile.Optimize
and add calls to the new partial evaluator in GF.Compile.GeneratePMCFG.
This also means that -new-comp effectively implies -noexpand.

In GF.Compile.CheckGrammar, there is a check that restricted inheritance is used
correctly. However, when -noexpand is used, this check causes unexpected errors,
so it has been converted to generate warnings, for now.

-new-comp no longer enables the new type checker in
GF.Compile.Typeckeck.ConcreteNew.

The GF version number has been bumped to 3.3.10-darcs

src/compiler/GF/Infra/Option.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 module GF.Infra.Option
     (
      -- * Option types
@@ -256,11 +257,7 @@ defaultFlags = Flags {
       optPreprocessors   = [],
       optEncoding        = "latin1",
       optPMCFG           = True,
--- #ifdef CC_LAZY
---       optOptimizations   = Set.fromList [OptStem,OptCSE],
--- #else
       optOptimizations   = Set.fromList [OptStem,OptCSE,OptExpand,OptParametrize],
--- #endif
       optOptimizePGF     = False,
       optMkIndexPGF     = False,
       optCFGTransforms   = Set.fromList [CFGRemoveCycles, CFGBottomUpFilter, 
@@ -273,7 +270,12 @@ defaultFlags = Flags {
       optWarnings        = [],
       optDump            = [],
       optTagsOnly        = False,
-      optNewComp         = False
+      optNewComp         =
+#ifdef NEW_COMP
+                           True
+#else
+                           False
+#endif
     }
 
 -- Option descriptions
@@ -352,6 +354,7 @@ optDescr =
      Option [] ["cse"] (onOff (toggleOptimize OptCSE) True) "Perform common sub-expression elimination (default on).",
      Option [] ["cfg"] (ReqArg cfgTransform "TRANS") "Enable or disable specific CFG transformations. TRANS = merge, no-merge, bottomup, no-bottomup, ...",
      Option [] ["new-comp"] (NoArg (set $ \o -> o{optNewComp = True})) "Use the new experimental compiler.",
+     Option [] ["old-comp"] (NoArg (set $ \o -> o{optNewComp = False})) "Use old trusty compiler.",
      dumpOption "source" Source,
      dumpOption "rebuild" Rebuild,
      dumpOption "extend" Extend,