The distinction makes no sense since Spot 0.5, where we switched from
mutable furmulae to immutable formulae.  The difference between
const_visitor and visitor made no sense either.  They have been merged
into one: visitor.

* iface/dve2/dve2check.cc, iface/gspn/ltlgspn.cc,
src/eltlparse/eltlparse.yy, src/eltlparse/public.hh,
src/evtgbatest/ltl2evtgba.cc, src/kripkeparse/kripkeparse.yy,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/automatop.cc, src/ltlast/automatop.hh, src/ltlast/binop.cc,
src/ltlast/binop.hh, src/ltlast/bunop.cc, src/ltlast/bunop.hh,
src/ltlast/constant.cc, src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.hh, src/ltlast/formula_tree.cc,
src/ltlast/formula_tree.hh, src/ltlast/multop.cc,
src/ltlast/multop.hh, src/ltlast/predecl.hh, src/ltlast/refformula.cc,
src/ltlast/refformula.hh, src/ltlast/unop.cc, src/ltlast/unop.hh,
src/ltlast/visitor.hh, src/ltlenv/declenv.cc, src/ltlenv/declenv.hh,
src/ltlenv/defaultenv.cc, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/ltlfile.cc,
src/ltlparse/ltlfile.hh, src/ltlparse/ltlparse.yy,
src/ltlparse/public.hh, src/ltltest/consterm.cc,
src/ltltest/equals.cc, src/ltltest/genltl.cc, src/ltltest/kind.cc,
src/ltltest/length.cc, src/ltltest/randltl.cc, src/ltltest/readltl.cc,
src/ltltest/reduc.cc, src/ltltest/syntimpl.cc,
src/ltltest/tostring.cc, src/ltlvisit/apcollect.cc,
src/ltlvisit/apcollect.hh, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/contain.cc,
src/ltlvisit/contain.hh, src/ltlvisit/dotty.cc,
src/ltlvisit/length.cc, src/ltlvisit/lunabbrev.cc,
src/ltlvisit/lunabbrev.hh, src/ltlvisit/mark.cc, src/ltlvisit/mark.hh,
src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh,
src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh,
src/ltlvisit/randomltl.cc, src/ltlvisit/randomltl.hh,
src/ltlvisit/reduce.cc, src/ltlvisit/reduce.hh,
src/ltlvisit/simpfg.cc, src/ltlvisit/simpfg.hh,
src/ltlvisit/simplify.cc, src/ltlvisit/simplify.hh,
src/ltlvisit/snf.cc, src/ltlvisit/snf.hh, src/ltlvisit/tostring.cc,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/ltlvisit/wmunabbrev.cc, src/ltlvisit/wmunabbrev.hh,
src/neverparse/neverclaimparse.yy, src/sabatest/sabacomplementtgba.cc,
src/tgba/bdddict.cc, src/tgba/formula2bdd.cc, src/tgba/taatgba.cc,
src/tgba/taatgba.hh, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_lacim.cc, src/tgbaalgos/minimize.cc,
src/tgbaalgos/randomgraph.cc, src/tgbaparse/tgbaparse.yy,
src/tgbatest/complementation.cc, src/tgbatest/ltl2tgba.cc,
src/tgbatest/ltlprod.cc, src/tgbatest/mixprod.cc,
src/tgbatest/randtgba.cc: Massive adjustment!
* src/tgbatest/reductgba.cc: Delete.

* src/ltlvisit/simplify.cc (spot::ltl::is_And, spot::ltl::is_F,
spot::ltl::is_FG, spot::ltl::is_G, spot::ltl::is_GF, spot::ltl::is_M,
spot::ltl::is_Or, spot::ltl::is_R, spot::ltl::is_U, spot::ltl::is_W,
spot::ltl::is_X, spot::ltl::is_binop, spot::ltl::is_constant,
spot::ltl::is_multop, spot::ltl::is_unop): Move ...
* src/ltlast/binop.hh, src/ltlast/constant.hh, src/ltlast/multop.hh
src/ltlast/unop.hh: ... here, as appropriate.

* src/ltlast/binop.cc, src/ltlast/binop.hh: Here.
* doc/tl/tl.tex, src/ltltest/equals.test: Adjust.

* src/ltlast/binop.cc (EConcat, UConcat): Rewrite "{b}<>-> f"
as "b && f", and rewrite "{b}[]->f" as "b->f".
* src/ltlast/binop.hh (binop::instance): Document trivial
identities for <>-> and []->.
* src/ltlast/multop.cc (multop::instance): Rewrite "b1 & b2"
as "b1 && b2" when b1 and b2 are Boolean.
(multop::multop): Always disable is.boolean for AndNLM.
* src/ltlast/multop.hh: Document the rewriting.
* src/ltltest/equals.cc: Show the two formulas if the exit_code
is 1, to help debugging.
* src/ltltest/equals.test: Add more tests.
* src/ltltest/kind.test: Adjust tests.

* src/ltlast/binop.cc (binop::instance): Simplify fUf, fRf, fWf,
and fRF.
* src/ltlast/binop.hh: Document it.
* src/ltltest/equals.test: Add new tests for 'Exp U Exp'
and 'Exp R Exp', and all missing tests for W and M.

The new rewriting are (Exp => Exp) = 1, (Exp <=> Exp) == 1,
and (Exp ^ Exp) == 0.

* src/ltlast/binop.hh: Fix documentation.
* src/ltlast/binop.cc: Fix implementation.
* src/ltltest/equals.test: More tests.
* src/tgbatest/emptchk.test: Remove a useless test.

* src/ltlast/binop.cc, src/ltlast/binop.hh: Introduce
EConcatMarked ("<>+>").
* src/ltlvisit/basicreduce.cc, src/ltlvisit/consterm.cc,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/nenoform.cc,
src/ltlvisit/reduce.cc, src/ltlvisit/simpfg.cc,
src/ltlvisit/syntimpl.cc, src/ltlvisit/tostring.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2tgba_lacim.cc, src/tgba/formula2bdd.cc,
src/tgba/formula2bdd.cc: Deal with it if possible or ignore
it.

* src/ltlast/binop.hh, src/ltlast/binop.cc (EConcat, UConcat):
Add these new operators.
* src/ltlparse/ltlparse.yy, src/ltlparse/ltlscan.ll: Parse
these new operators.
* src/ltlvisit/simpfg.cc, src/ltlvisit/syntimpl.cc,
src/ltlvisit/tostring.cc, src/ltlvisit/basicreduce.cc,
src/ltlvisit/consterm.cc, src/ltlvisit/lunabbrev.cc,
src/ltlvisit/nenoform.cc, src/ltlvisit/reduce.cc
src/tgba/formula2bdd.cc, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_lacim.cc: Add these new operators into the
switches.

Trivial simplifications rules (such as "FFa=Fa" or "x&1=x")
are performed any time a formule is instanciated.

* src/ltlast/constant.hh, src/ltlast/constant.cc
(true_instance, true_instance_): Declare the true_instance_ as a
static member, and move true_instance() into the .hh so it gets
inlined.  Have true_instance_ as a class variable will ensure that
it is the first formula instantiated.  Binop simplifications rely
on this to order arguments.
(false_instance, false_instance_): Likewise.
(empty_word_instance, empty_word_instance_): New method and static
member.
* src/ltlast/formula.hh (formula::formula): If max_count_ ever
loops, skip the first three values so that constants always have
smaller hash codes.
* src/ltlast/binop.hh, src/ltlast/binop.cc (instance): Add
simplifications and document them.
* src/ltlast/multop.hh (multop::Concat): New operator.
* src/ltlast/multop.cc (op_name): Handle Concat.
(instance): Inline Concat arguments without reordering.  Handle
absorbent and neutral elements for all operators.
* src/ltlast/unop.hh (unop::Star): New operator.
* src/ltlast/unop.cc (op_name): Handle Star.
(instance): Handle Star, and add trivial simplifications for
other unary operators.
* src/ltlparse/ltlparse.yy (OP_CONCAT, OP_STAR, CONST_EMPTYWORD):
Declare these new operators and add rules for them.
* src/ltlparse/ltlscan.ll (OP_CONCAT, OP_STAR, CONST_EMPTYWORD):
Output these new operators.
* src/ltltest/equals.test: New tests.
* src/ltltest/parse.test: Remove redundant test.
* src/ltltest/tunabbrev.test, src/tgbatest/emptchk.test: Adjust tests.
* src/ltlvisit/basicreduce.cc, src/ltlvisit/contain.cc,
src/ltlvisit/nenoform.cc, src/ltlvisit/reduce.cc,
src/ltlvisit/syntimpl.cc, src/ltlvisit/tostring.cc,
src/ltlvisit/tunabbrev.cc: Complete visitors to handle new
operators.
* src/ltltest/nenoform.test: More tests.
* src/ltlvisit/lunabbrev.cc (unabbreviate_logic_visitor::visit):
Clone formulae before instance() function actually have a chance
to destroy them.
* src/tgba/formula2bdd.cc, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_lacim.cc: Adjust switches to assert on new
operators.

* src/ltlast/binop.cc, src/ltlast/binop.cc: Add support for
these new operators.
* src/ltlparse/ltlparse.yy, src/ltlparse/ltlscan.ll: Parse them.
* src/ltltest/reduccmp.test: Add new tests for W and M.
* src/ltlvisit/basicreduce.cc, src/ltlvisit/contain.cc,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/nenoform.cc,
src/ltlvisit/randomltl.cc, src/ltlvisit/randomltl.hh,
src/ltlvisit/reduce.cc, src/ltlvisite/simpfg.cc,
src/ltlvisit/simpfg.hh, src/ltlvisit/syntimpl.cc,
src/ltlvisit/tostring.cc, src/tgba/formula2bdd.cc,
src/tgbaalgos/eltl2tgba_lacim.cc, src/tgbaalgos/ltl2taa.cc,
src/tgbaalgos/ltl2tgba_fm.cc, src/tgbaalgos/ltl2tgba_lacim.cc:
Add support for W and M.
* src/tgbatest/ltl2neverclaim.test: Test never claim output
using LBTT, this is more thorough.  Also we cannot use -N
any more in the spotlbtt.test.
* src/tgbatests/ltl2tgba.cc: Define M and W for ELTL.
* src/tgbatest/ltl2neverclaim.test: Test W and M, and use
-DS instead of -N, because lbtt-translate does not want
to translate these operators for tools that masquerade as Spin.

* bench/Makefile.am, bench/gspn-ssp/Makefile.am,
bench/gspn-ssp/defs.in, bench/scc-stats/Makefile.am,
bench/split-product/Makefile.am, configure.ac,
iface/Makefile.am, iface/gspn/Makefile.am, iface/gspn/ssp.hh,
iface/nips/Makefile.am, iface/nips/common.cc,
iface/nips/common.hh, iface/nips/dottynips.cc,
iface/nips/nips.cc, iface/nips/nips.hh, src/Makefile.am,
src/eltlparse/Makefile.am, src/eltlparse/eltlparse.yy,
src/eltlparse/eltlscan.ll, src/eltlparse/fmterror.cc,
src/eltlparse/parsedecl.hh, src/eltltest/Makefile.am,
src/eltltest/defs.in, src/eltltest/nfa.cc, src/evtgba/evtgba.hh,
src/evtgba/product.cc, src/evtgba/product.hh,
src/evtgbaalgos/tgba2evtgba.cc, src/evtgbaparse/Makefile.am,
src/evtgbaparse/evtgbaparse.yy, src/evtgbatest/defs.in,
src/evtgbatest/explicit.test, src/evtgbatest/ltl2evtgba.cc,
src/evtgbatest/ltl2evtgba.test, src/evtgbatest/product.cc,
src/evtgbatest/product.test, src/evtgbatest/readsave.cc,
src/evtgbatest/readsave.test, src/ltlast/atomic_prop.cc,
src/ltlast/atomic_prop.hh, src/ltlast/binop.cc,
src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.hh, src/ltlast/formula_tree.cc,
src/ltlast/formula_tree.hh, src/ltlast/multop.cc,
src/ltlast/multop.hh, src/ltlast/nfa.cc, src/ltlast/nfa.hh,
src/ltlast/unop.cc, src/ltlast/unop.hh, src/ltlenv/declenv.cc,
src/ltlenv/declenv.hh, src/ltlenv/environment.hh,
src/ltlparse/Makefile.am, src/ltlparse/ltlparse.yy,
src/ltltest/Makefile.am, src/ltltest/defs.in,
src/ltltest/equals.cc, src/ltltest/equals.test,
src/ltltest/lunabbrev.test, src/ltltest/nenoform.test,
src/ltltest/parse.test, src/ltltest/parseerr.test,
src/ltltest/randltl.cc, src/ltltest/readltl.cc,
src/ltltest/reduccmp.test, src/ltltest/syntimpl.cc,
src/ltltest/syntimpl.test, src/ltltest/tostring.cc,
src/ltltest/tostring.test, src/ltltest/tunabbrev.test,
src/ltltest/tunenoform.test, src/ltlvisit/basicreduce.cc,
src/ltlvisit/clone.cc, src/ltlvisit/clone.hh,
src/ltlvisit/contain.cc, src/ltlvisit/destroy.cc,
src/ltlvisit/destroy.hh, src/ltlvisit/lunabbrev.cc,
src/ltlvisit/nenoform.cc, src/ltlvisit/randomltl.cc,
src/ltlvisit/reduce.cc, src/ltlvisit/syntimpl.cc,
src/ltlvisit/tostring.cc, src/misc/bddalloc.cc,
src/misc/bddop.cc, src/misc/bddop.hh, src/misc/freelist.hh,
src/misc/hash.hh, src/misc/minato.cc, src/misc/minato.hh,
src/misc/optionmap.cc, src/misc/timer.cc, src/misc/timer.hh,
src/saba/Makefile.am, src/saba/explicitstateconjunction.cc,
src/saba/explicitstateconjunction.hh, src/saba/saba.cc,
src/saba/saba.hh, src/saba/sabacomplementtgba.cc,
src/saba/sabacomplementtgba.hh, src/saba/sabastate.hh,
src/saba/sabasucciter.hh, src/sabaalgos/Makefile.am,
src/sabaalgos/sabadotty.cc, src/sabaalgos/sabadotty.hh,
src/sabaalgos/sabareachiter.cc, src/sabaalgos/sabareachiter.hh,
src/sabatest/Makefile.am, src/sabatest/defs.in,
src/sanity/Makefile.am, src/tgba/Makefile.am,
src/tgba/bdddict.cc, src/tgba/bddprint.cc,
src/tgba/formula2bdd.cc, src/tgba/state.hh,
src/tgba/succiterconcrete.cc, src/tgba/taatgba.hh,
src/tgba/tgba.hh, src/tgba/tgbabddconcretefactory.cc,
src/tgba/tgbabddconcretefactory.hh, src/tgba/tgbacomplement.cc,
src/tgba/tgbacomplement.hh, src/tgba/tgbaexplicit.cc,
src/tgba/tgbaexplicit.hh, src/tgba/tgbaproduct.cc,
src/tgba/tgbareduc.cc, src/tgba/tgbareduc.hh,
src/tgba/tgbasafracomplement.cc, src/tgba/tgbasgba.cc,
src/tgba/tgbasgba.hh, src/tgba/tgbaunion.cc,
src/tgba/tgbaunion.hh, src/tgbaalgos/dupexp.cc,
src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/eltl2tgba_lacim.hh, src/tgbaalgos/emptiness.cc,
src/tgbaalgos/gtec/gtec.cc, src/tgbaalgos/ltl2taa.cc,
src/tgbaalgos/ltl2taa.hh, src/tgbaalgos/ltl2tgba_lacim.cc,
src/tgbaalgos/neverclaim.cc, src/tgbaalgos/neverclaim.hh,
src/tgbaalgos/powerset.cc, src/tgbaalgos/reachiter.cc,
src/tgbaalgos/reachiter.hh, src/tgbaalgos/reductgba_sim.cc,
src/tgbaalgos/reductgba_sim.hh,
src/tgbaalgos/reductgba_sim_del.cc, src/tgbaalgos/stats.cc,
src/tgbaalgos/stats.hh, src/tgbaparse/Makefile.am,
src/tgbaparse/tgbaparse.yy, src/tgbatest/Makefile.am,
src/tgbatest/bddprod.test, src/tgbatest/complementation.cc,
src/tgbatest/complementation.test, src/tgbatest/defs.in,
src/tgbatest/dfs.test, src/tgbatest/dupexp.test,
src/tgbatest/explicit.cc, src/tgbatest/explicit.test,
src/tgbatest/explpro3.test, src/tgbatest/explpro4.test,
src/tgbatest/explprod.cc, src/tgbatest/explprod.test,
src/tgbatest/ltl2neverclaim.test, src/tgbatest/ltl2tgba.cc,
src/tgbatest/ltl2tgba.test, src/tgbatest/ltlprod.cc,
src/tgbatest/ltlprod.test, src/tgbatest/mixprod.cc,
src/tgbatest/mixprod.test, src/tgbatest/powerset.cc,
src/tgbatest/readsave.cc, src/tgbatest/readsave.test,
src/tgbatest/reduccmp.test, src/tgbatest/reductgba.cc,
src/tgbatest/reductgba.test, src/tgbatest/taatgba.cc,
src/tgbatest/tgbaread.cc, src/tgbatest/tgbaread.test,
src/tgbatest/tripprod.cc, src/tgbatest/tripprod.test,
wrap/python/cgi/ltl2tgba.in, wrap/python/tests/ltl2tgba.py,
wrap/python/tests/ltlparse.py, wrap/python/tests/ltlsimple.py:
Fix copyrights.

counter updated each time we create a new (unique) formula.

Doing so saves a lot of memory during the translation of the
ltlcounter formulae, because the formulae are quite big and
storing a string representation of each formula on its node was a
bad idea.  For instance with n=12, the translation now uses 40MB
where it used 290MB.  (Note: in both cases, 20MB is being used by
the BDD cache.)

* src/ltlast/formula.hh (hash_key_): Rename as ...
(count_): ... this.
(hash): Adjust.
(max_count): New static variable to count the number of
formulae created.
(formula): Update max_count and set count_.
(dump): Make it a virtual pure method.
(set_key_): Remove.
(formula_ptr_less_than): Speed up and return false when
the two formula pointer are equal.
* src/ltlast/formula.cc (set_key_, dump): Remove.
* src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/automatop.cc, src/ltlast/automatop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/multop.cc,
src/ltlast/multop.hh, src/ltlast/unop.cc, src/ltlast/unop.hh:
Empty the constructor (do not precompute the dump_ anymore),
and add a dump() implementation.

* src/ltlast/automatop.cc, src/ltlast/automatop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/multop.cc,
src/ltlast/multop.hh, src/ltlast/unop.cc, src/ltlast/unop.hh:
Add a dump_instance() static method to all class.
* src/ltltest/readltl.cc: Add option -r to dump all instances
with their reference count, after parsing and after deletion.

* src/ltlast/unop.hh (map): Use unop* as values.
* src/ltlast/binop.hh (map): Use binop* as values.
* src/ltlast/multop.hh (map): Use multop* as values.
* src/ltlast/automatop.hh (paircmp): Rename as tripletcmp.
(map): Use automaton* as values, not formula*.

Here are the reverted patches:
8c0d1003,
25a31142,
9afbaf63,
dc0005f4,
543190f2.

src/ltlast/constant.hh, src/ltlast/formula.hh,
src/ltlast/multop.hh, src/ltlast/refformula.hh,
src/ltlast/unop.hh, src/ltlast/visitor.hh, src/ltlenv/declenv.hh,
src/ltlenv/defaultenv.hh, src/ltlenv/environment.hh,
src/ltlparse/public.hh, src/ltlvisit/apcollect.hh,
src/ltlvisit/basicreduce.hh, src/ltlvisit/clone.hh,
src/ltlvisit/destroy.hh, src/ltlvisit/dotty.hh,
src/ltlvisit/dump.hh, src/ltlvisit/length.hh,
src/ltlvisit/lunabbrev.hh, src/ltlvisit/nenoform.hh: Add Doxygen
groups for LTL algorithms and types.
* doc/Makefile.am (fast-doc): New target.

src/ltlast/binop.hh, src/ltlast/constant.hh,
src/ltlast/formula.hh, src/ltlast/multop.hh,
src/ltlast/predecl.hh, src/ltlast/refformula.hh,
src/ltlast/unop.hh, src/ltlast/visitor.hh: Use file to introduce
each file.

* Makefile.am, configure.ac, doc/Makefile.am, iface/Makefile.am,
iface/gspn/Makefile.am, iface/gspn/common.cc,
iface/gspn/common.hh, iface/gspn/dottyeesrg.cc,
iface/gspn/dottygspn.cc, iface/gspn/eesrg.cc, iface/gspn/eesrg.hh,
iface/gspn/gspn.cc, iface/gspn/gspn.hh, iface/gspn/ltlgspn.cc,
src/Makefile.am, src/ltlast/Makefile.am, src/ltlast/allnodes.hh,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.hh, src/ltlast/multop.cc, src/ltlast/multop.hh,
src/ltlast/predecl.hh, src/ltlast/refformula.cc,
src/ltlast/refformula.hh, src/ltlast/unop.cc, src/ltlast/unop.hh,
src/ltlast/visitor.hh, src/ltlenv/Makefile.am,
src/ltlenv/defaultenv.cc, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/Makefile.am,
src/ltlparse/fmterror.cc, src/ltlparse/ltlparse.yy,
src/ltlparse/ltlscan.ll, src/ltlparse/parsedecl.hh,
src/ltlparse/public.hh, src/ltltest/Makefile.am,
src/ltltest/defs.in, src/ltltest/equals.cc,
src/ltltest/equals.test, src/ltltest/lunabbrev.test,
src/ltltest/nenoform.test, src/ltltest/parse.test,
src/ltltest/parseerr.test, src/ltltest/readltl.cc,
src/ltltest/tostring.cc, src/ltltest/tostring.test,
src/ltltest/tunabbrev.test, src/ltltest/tunenoform.test,
src/ltlvisit/Makefile.am, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/destroy.cc,
src/ltlvisit/destroy.hh, src/ltlvisit/dotty.cc,
src/ltlvisit/dotty.hh, src/ltlvisit/dump.cc, src/ltlvisit/dump.hh,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh,
src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh,
src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/misc/Makefile.am, src/misc/bddalloc.cc, src/misc/bddalloc.hh,
src/misc/bddlt.hh, src/misc/hash.hh, src/misc/minato.cc,
src/misc/minato.hh, src/misc/version.cc, src/misc/version.hh,
src/tgba/Makefile.am, src/tgba/bdddict.cc, src/tgba/bdddict.hh,
src/tgba/bddprint.cc, src/tgba/bddprint.hh, src/tgba/public.hh,
src/tgba/state.hh, src/tgba/statebdd.cc, src/tgba/statebdd.hh,
src/tgba/succiter.hh, src/tgba/succiterconcrete.cc,
src/tgba/succiterconcrete.hh, src/tgba/tgba.cc, src/tgba/tgba.hh,
src/tgba/tgbabddconcrete.cc, src/tgba/tgbabddconcrete.hh,
src/tgba/tgbabddconcretefactory.cc,
src/tgba/tgbabddconcretefactory.hh,
src/tgba/tgbabddconcreteproduct.cc,
src/tgba/tgbabddconcreteproduct.hh, src/tgba/tgbabddcoredata.cc,
src/tgba/tgbabddcoredata.hh, src/tgba/tgbabddfactory.hh,
src/tgba/tgbaexplicit.cc, src/tgba/tgbaexplicit.hh,
src/tgba/tgbaproduct.cc, src/tgba/tgbaproduct.hh,
src/tgba/tgbatba.cc, src/tgba/tgbatba.hh,
src/tgbaalgos/Makefile.am, src/tgbaalgos/dotty.cc,
src/tgbaalgos/dotty.hh, src/tgbaalgos/dupexp.cc,
src/tgbaalgos/dupexp.hh, src/tgbaalgos/emptinesscheck.cc,
src/tgbaalgos/emptinesscheck.hh, src/tgbaalgos/lbtt.cc,
src/tgbaalgos/lbtt.hh, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_fm.hh, src/tgbaalgos/ltl2tgba_lacim.cc,
src/tgbaalgos/ltl2tgba_lacim.hh, src/tgbaalgos/magic.cc,
src/tgbaalgos/magic.hh, src/tgbaalgos/reachiter.cc,
src/tgbaalgos/reachiter.hh, src/tgbaalgos/save.cc,
src/tgbaalgos/save.hh, src/tgbaparse/Makefile.am,
src/tgbaparse/fmterror.cc, src/tgbaparse/parsedecl.hh,
src/tgbaparse/public.hh, src/tgbaparse/tgbaparse.yy,
src/tgbaparse/tgbascan.ll, src/tgbatest/Makefile.am,
src/tgbatest/bddprod.test, src/tgbatest/defs.in,
src/tgbatest/dupexp.test, src/tgbatest/emptchk.test,
src/tgbatest/emptchke.test, src/tgbatest/explicit.test,
src/tgbatest/explpro2.test, src/tgbatest/explpro3.test,
src/tgbatest/explprod.test, src/tgbatest/ltl2tgba.test,
src/tgbatest/ltlprod.test, src/tgbatest/mixprod.test,
src/tgbatest/readsave.test, src/tgbatest/spotlbtt.test,
src/tgbatest/tgbaread.test, src/tgbatest/tripprod.test,
wrap/Makefile.am, wrap/python/Makefile.am, wrap/python/buddy.i,
wrap/python/spot.i, wrap/python/cgi/Makefile.am,
wrap/python/cgi/ltl2tgba.in, wrap/python/tests/Makefile.am,
wrap/python/tests/bddnqueen.py, wrap/python/tests/interdep.py,
wrap/python/tests/ltl2tgba.py, wrap/python/tests/ltl2tgba.test,
wrap/python/tests/ltlparse.py, wrap/python/tests/ltlsimple.py,
wrap/python/tests/run.in: Add Copyright license.

* src/ltlast/atomic_prop.hh: Declare instance_count().
* src/ltlast/binop.hh, src/ltlast/unop.hh, src/ltlast/multop.hh:
Likewise.  Also, really inherit for ref_formula this time.
* src/ltlast/atomic_prop.cc, src/ltlast/binop.cc,
src/ltlast/unop.cc, src/ltlast/multop.cc: On destruction, suppress
the instance from the instance map.  Implement instance_count().
* src/ltlast/formula.cc, src/ltlast/formula.hh,
src/ltlast/ref_formula.cc, src/ltlast/ref_formula.hh: Add virtual
destructors.
* src/ltlparse/ltlparse.yy: Recover from binary operators with
missing right hand operand (the point is just to destroy the
the left hand operand).
* src/ltltest/equals.cc, src/ltltest/readltl.cc,
src/ltltest/tostring.cc: Destroy used formulae.  Make sure
instance_count()s are null are the end.
* src/ltltest/parseerr.test: Adjust expected result, now
that the parser lnows about missing right hand operands.
* src/ltlvisit/destroy.hh, src/ltlvisit/destroy.cc,
src/ltlvisit/postfix.hh, src/ltlvisit/postfix.cc: New files.
* src/ltlvisit/Makefile.am (libltlvisit_la_SOURCES): Add them.
* src/ltlvisit/lunabbrev.cc (Xor, Equiv): Clone formulae
occurring twice in the rewritten expression.

reference-counted formula*.  One can't call constructors for AST
items anymore, everything need to be acquired through instance()
class methods.

* src/ltlast/formula.cc, src/ltlast/refformula.cc,
src/ltlast/refformula.hh: New files.
* src/ltlast/Makefile.am (libltlast_la_SOURCES): Add them.
* src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/unop.cc, src/ltlast/unop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh: Make the constructor
and destructor protected.  Define a static function `instance()'
to get an instance with specific argument.  Use a map called
`instances' to store all known instances.  Inherit from
ref_formula.
* src/ltlast/constant.hh, src/ltlast/constant.cc: Protect
the constructor and destructor.  Provide the false_instance()
and true_instance() functions instead.
* src/formula.hh (ref, unref, ref_, unref_): New methods.
* src/ltlast/multop.cc, src/ltlast/multop.hh: Protect
the constructor, destructor, as well as the add() method.
Provides the instance(), and add() class methods instead.
Store children_ as a pointer.
* src/ltlenv/defaultenv.cc (require): Adjust to
call atomic_prop::instance.
* src/ltlparse/ltlparse.yy: Adjust to call instance() functions
instead of constructors.
* src/ltltest/Makefile.am (LDADD): Tweak library ordering.
* src/ltlvisit/clone.hh (clone_visitor): Inherit from visitor,
not const_visitor, and adjust all prototypes appropriately.
* src/ltlvisit/clone.cc (clone_visitor): Likewise.
Call ref() or instance() methods instead of copy constructors.
* src/ltlvisit/equals.cc: Simplify atomic_prop and constant
cases.
* src/ltlvisit/lunabbrev.hh, src/ltlvisit/lunabbrev.cc,
src/ltlvisit/tunabbrev.hh, src/ltlvisit/tunabbrev.cc,
src/ltlvisit/nenoform.hh, src/ltlvisit/nenoform.cc: Use instance()
methods instead of constructor.  Make these children of visitor, not
const_visitor.
* src/ltltest/readltl.c (main): Do not delete the formula.

src/ltlast/constant.hh, src/ltlast/formula.hh,
src/ltlast/multop.hh, src/ltlast/unop.hh, src/ltlast/visitor.hh,
src/ltlenv/defaultenv.hh, src/ltlenv/environment.hh,
src/ltlparse/public.hh, src/ltlvisit/clone.hh,
src/ltlvisit/dotty.hh, src/ltlvisit/dump.hh,
src/ltlvisit/equals.hh, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/nenoform.hh, src/ltlvisit/tunabbrev.hh: Add
Doxygen comments.
* src/visitor.hh: Do not use const_sel.  This clarify
the code and helps Doxygen.

* src/ltlast/formula.hh: ... this.
* src/ltlast/Makefile.am (libltlast_a_SOURCES): Adjust.
* src/ltlast/formula.hh (formulae): Rename as ...
(formula): ... this.
Adjust all uses.

* src/ltlast/unop.hh (unop::equals): Remove.
* src/ltlast/unop.cc (unop::equals): Remove.
* src/ltlast/binop.hh (binop::equals): Remove.
* src/ltlast/binop.cc (binop::equals): Remove.
* src/ltlast/multop.hh (multop::equals): Remove.
* src/ltlast/multop.cc (multop::equals): Remove.
* src/ltlast/atomic_prop.hh (atomic_prop::equals): Remove.
* src/ltlast/atomic_prop.cc (atomic_prop::equals): Remove.
* src/ltlast/constant.hh (constant::equals): Remove.
* src/ltlast/constant.cc (constant::equals): Remove.

src/Makefile.am, src/ltlast/Makefile.am, src/ltlast/allnodes.hh,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/formulae.hh,
src/ltlast/multop.cc, src/ltlast/multop.hh, src/ltlast/predecl.hh,
src/ltlast/unop.cc, src/ltlast/unop.hh, src/ltlast/visitor.hh,
src/ltlparse/Makefile.am, src/ltlparse/ltlparse.yy,
src/ltlparse/ltlscan.ll, src/ltlparse/parsedecl.hh,
src/ltlparse/public.hh, src/ltlvisit/Makefile.am,
src/ltlvisit/dotty.cc, src/ltlvisit/dotty.hh,
src/ltlvisit/dump.cc, src/ltlvisit/dump.hh,
src/ltlvisit/rewrite.cc, src/ltlvisit/rewrite.hh,
src/ltltest/Makefile.am, src/ltltest/defs.in, src/ltltest/readltl.cc,
src/ltltest/parse.test, src/ltltest/parseerr.test,
src/misc/Makefile.am, src/misc/const_sel.hh: New files.