Introduce rational operators and trivial simplification rules.

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.
This commit is contained in:
Alexandre Duret-Lutz 2010-01-11 14:29:46 +01:00
parent 4fcc4f829c
commit 546559b8c3
29 changed files with 575 additions and 120 deletions

View file

@ -1,8 +1,8 @@
// Copyright (C) 2009 Laboratoire de Recherche et Développement
// Copyright (C) 2009, 2010 Laboratoire de Recherche et D<>veloppement
// de l'Epita (LRDE).
// Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris
// 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
// Université Pierre et Marie Curie.
// 6 (LIP6), d<EFBFBD>partement Syst<73>mes R<>partis Coop<6F>ratifs (SRC),
// Universit<EFBFBD> Pierre et Marie Curie.
//
// This file is part of Spot, a model checking library.
//
@ -38,12 +38,10 @@ namespace spot
/// \brief Multi-operand operators.
/// \ingroup ltl_ast
///
/// These operators are considered commutative and associative.
class multop : public ref_formula
{
public:
enum type { Or, And };
enum type { Or, And, Concat };
/// List of formulae.
typedef std::vector<formula*> vec;
@ -51,29 +49,46 @@ namespace spot
/// \brief Build a spot::ltl::multop with two children.
///
/// If one of the children itself is a spot::ltl::multop
/// with the same type, it will be merged. I.e., children
/// if that child will be added, and that child itself will
/// with the same type, it will be inlined. I.e., children
/// of that child will be added, and that child itself will
/// be destroyed. This allows incremental building of
/// n-ary ltl::multop.
///
/// This functions can perform slight optimizations and
/// may not return an ltl::multop objects. For instance
/// if \c first and \c second are equal, that formula is
/// returned as-is.
/// may not return an ltl::multop object. See the other
/// instance function for the list of rewritings.
static formula* instance(type op, formula* first, formula* second);
/// \brief Build a spot::ltl::multop with many children.
///
/// Same as the other instance() function, but take a vector of
/// formula in argument. This vector is acquired by the
/// formulae as argument. This vector is acquired by the
/// spot::ltl::multop class, the caller should allocate it with
/// \c new, but not use it (especially not destroy it) after it
/// has been passed to spot::ltl::multop.
///
/// This functions can perform slight optimizations and
/// may not return an ltl::multop objects. For instance
/// if the vector contain only one unique element, this
/// this formula will be returned as-is.
/// All operators (Or, And, Concat) are associative, and are
/// automatically inlined. Or and And are commutative, so their
/// argument are also sorted, to ensure that "a & b" is equal to
/// "b & a". For Or and And, duplicate arguments are also
/// removed.
///
/// Furthermore this function can perform slight optimizations
/// and may not return an ltl::multop object. For instance if
/// the vector contains only one unique element, this this
/// formula will be returned as-is. Neutral and absorbent element
/// are also taken care of. The following rewriting are performed
/// (the left patterns are rewritten as shown on the right):
///
/// - Concat(Exps1...,#e,Exps2...) = Concat(Exps1...,Exps2...)
/// - Concat(Exps1...,0,Exps2...) = 0
/// - Concat(Exp) = Exp
/// - And(Exps1...,1,Exps2...) = And(Exps1...,Exps2...)
/// - And(Exps1...,0,Exps2...) = 0
/// - And(Exp) = Exp
/// - Or(Exps1...,1,Exps2...) = 1
/// - Or(Exps1...,0,Exps2...) = And(Exps1...,Exps2...)
/// - Or(Exp) = Exp
static formula* instance(type op, vec* v);
virtual void accept(visitor& v);