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Introduce [=min..max] operator.

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* src/ltlast/bunop.hh: Declare bunop::Equal
* src/ltlast/bunop.cc: Handle it.
* src/ltlparse/ltlparse.yy,
src/ltlparse/ltlscan.ll: Add rules for [=min..max].
* src/tgbaalgos/ltl2tgba_fm.cc: Handle bunop::Equal in
the translation.
* src/ltltest/equals.test: Test trivial identities
for [=min..max].
* src/tgbatest/ltl2tgba.test: Add new formulae to test.
This commit is contained in:
Alexandre Duret-Lutz 2010-10-14 18:51:34 +02:00
parent d7781bc4d6
commit 8d4a413a37
7 changed files with 236 additions and 91 deletions
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186
src/ltlast/bunop.cc
View file

@ -24,6 +24,8 @@
#include <iostream>
#include <sstream>
#include "constant.hh"
#include "unop.hh"
#include "ltlvisit/kind.hh"
namespace spot
{
@ -107,6 +109,8 @@ namespace spot
{
switch (op_)
{
case Equal:
return "Equal";
case Star:
return "Star";
}
@ -120,14 +124,22 @@ namespace spot
{
std::ostringstream out;
// Syntactic sugaring
if (min_ == 1 && max_ == unbounded)
switch (op_)
{
out << "[+]";
return out.str();
case Star:
// Syntactic sugaring
if (min_ == 1 && max_ == unbounded)
{
out << "[+]";
return out.str();
}
out << "[*";
break;
case Equal:
out << "[=";
break;
}
out << "[*";
if (min_ != 0 || max_ != unbounded)
{
out << min_;
@ -151,73 +163,115 @@ namespace spot
// Some trivial simplifications.
// - [*0][*min..max] = [*0]
if (child == constant::empty_word_instance())
return child;
// - 0[*0..max] = [*0]
// - 0[*min..max] = 0 if min > 0
if (child == constant::false_instance())
switch (op)
{
if (min == 0)
return constant::empty_word_instance();
else
return child;
}
case Equal:
{
// - 0[=0..max] = [*]
// - 0[=min..max] = 0 if min > 0
if (child == constant::false_instance())
{
if (min == 0)
{
max = -1U;
op = Star;
child = constant::true_instance();
break;
}
else
return child;
}
// - 1[=0] = [*0]
// - 1[=min..max] = 1[*min..max]
if (child == constant::true_instance())
{
if (max == 0)
return constant::empty_word_instance();
else
{
op = Star;
break;
}
}
// - Exp[=0] = (!Exp)[*]
if (max == 0)
return bunop::instance(bunop::Star,
unop::instance(unop::Not, child));
break;
}
case Star:
{
// - [*0][*min..max] = [*0]
if (child == constant::empty_word_instance())
return child;
// - Exp[*0..0] = [*0]
if (max == 0)
{
child->destroy();
return constant::empty_word_instance();
}
// - 0[*0..max] = [*0]
// - 0[*min..max] = 0 if min > 0
if (child == constant::false_instance())
{
if (min == 0)
return constant::empty_word_instance();
else
return child;
}
// - Exp[*i..j][*min..max] = Exp[*i(min)..j(max)] if i*(min+1)<=j(min)+1.
bunop* s = dynamic_cast<bunop*>(child);
if (s)
{
unsigned i = s->min();
unsigned j = s->max();
// - Exp[*0] = [*0]
if (max == 0)
{
child->destroy();
return constant::empty_word_instance();
}
// Exp has to be true between i*min and j*min
// then between i*(min+1) and j*(min+1)
// ...
// finally between i*max and j*max
//
// We can merge these intervals into [i*min..j*max] iff the
// first are adjacent or overlap, i.e. iff
// i*(min+1) <= j*min+1.
// (Because i<=j, this entails that the other intervals also
// overlap).
// - Exp[*i..j][*min..max] = Exp[*i(min)..j(max)]
// if i*(min+1)<=j(min)+1.
bunop* s = dynamic_cast<bunop*>(child);
if (s)
{
unsigned i = s->min();
unsigned j = s->max();
formula* exp = s->child();
if (j == unbounded)
{
min *= i;
max = unbounded;
// Exp has to be true between i*min and j*min
// then between i*(min+1) and j*(min+1)
// ...
// finally between i*max and j*max
//
// We can merge these intervals into [i*min..j*max] iff the
// first are adjacent or overlap, i.e. iff
// i*(min+1) <= j*min+1.
// (Because i<=j, this entails that the other intervals also
// overlap).
// Exp[*min..max]
exp->clone();
child->destroy();
child = exp;
}
else
{
if (i * (min + 1) <= (j * min) + 1)
{
min *= i;
if (max != unbounded)
{
if (j == unbounded)
max = unbounded;
else
max *= j;
}
exp->clone();
child->destroy();
child = exp;
}
}
formula* exp = s->child();
if (j == unbounded)
{
min *= i;
max = unbounded;
// Exp[*min..max]
exp->clone();
child->destroy();
child = exp;
}
else
{
if (i * (min + 1) <= (j * min) + 1)
{
min *= i;
if (max != unbounded)
{
if (j == unbounded)
max = unbounded;
else
max *= j;
}
exp->clone();
child->destroy();
child = exp;
}
}
}
break;
}
}
pair p(pairo(op, child), pairu(min, max));

8
src/ltlast/bunop.hh
View file

@ -37,7 +37,7 @@ namespace spot
class bunop : public ref_formula
{
public:
enum type { Star };
enum type { Star, Equal };
static const unsigned unbounded = -1U;
@ -49,7 +49,13 @@ namespace spot
/// - 0[*0..max] = [*0]
/// - 0[*min..max] = 0 if min > 0
/// - [*0][*min..max] = [*0]
/// - Exp[*0] = [*0]
/// - Exp[*i..j][*k..l] = Exp[*ik..jl] if i*(k+1)<=jk+1.
/// - 0[=0..max] = 1[*]
/// - 0[=min..max] = 0 if min > 0
/// - 1[=0] = [*0]
/// - 1[=min..max] = 1[*min..max] if max > 0
/// - Exp[=0] = (!Exp)[*]
///
/// These rewriting rules imply that it is not possible to build
/// an LTL formula object that is SYNTACTICALLY equal to one of