alarsyo/spot
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

Get rid of bunop::Equal and bunop::Goto.

Browse source 
* src/ltlast/bunop.hh, src/ltlast/bunop.cc, src/ltlvisit/randomltl.cc,
src/ltlvisit/simplify.cc, src/ltlvisit/tostring.cc,
src/tgbaalgos/ltl2tgba_fm.cc: Remove all traces of these two
operators since they are not handled like sugar.
* doc/tl/tl.tex: Adjust documentation to reflect the fact that these
two operators are sugar.
This commit is contained in:
Alexandre Duret-Lutz 2012-04-15 00:13:42 +02:00
parent 210723e30c
commit abaf102746
7 changed files with 38 additions and 272 deletions
Download patch file Download diff file Expand all files Collapse all files

65
src/tgbaalgos/ltl2tgba_fm.cc
View file

@ -548,71 +548,6 @@ namespace spot
res_ |= now_to_concat();
}
return;
case bunop::Equal:
{
// b[=min..max] == (!b;b[=min..max]) | (b;b[=min-1..max-1])
// b[=0..max] == [*0] | (!b;b[=0..max]) | (b;b[=0..max-1])
// Note: b[=0] == (!b)[*] is a trivial identity, so it will
// never occur here.
formula* f1 = // !b;b[=min..max] or !b;b[->min..max]
multop::instance(multop::Concat,
unop::instance(unop::Not,
bo->child()->clone()),
bo->clone());
formula* f2 = // b;b[=min-1..max-1] or b;b[->min-1..max-1]
multop::instance(multop::Concat,
bo->child()->clone(),
bunop::instance(op,
bo->child()->clone(),
min2, max2));
f = multop::instance(multop::Or, f1, f2);
res_ = recurse_and_concat(f);
f->destroy();
if (min == 0)
res_ |= now_to_concat();
return;
}
case bunop::Goto:
{
// It is important to understand why we do not define Goto
// similarly to equal, i.e.:
//
// b[->min..max] == (!b;b[->min..max]) | (b;b[->min-1..max-1])
// b[->0..max] == [*0] | (!b;b[->0..max]) | (b;b[->0..max-1])
// Note: b[->0] == [*0] is a trivial identity, so it will
// never occur here.
//
// The above would be wrong when min=0.
// For instance consider {(c&!c)[->0..1]}<>->1
// This formula is equivalent to {[*0]}<>->1 which is false.
// However with above above rewritings, we get
// {[*0] | !(c&!c);(c&!c)[->0..1] | (c&!c);(c&!c)[->0] }<>->1
// which is equivalent to { 1;[*0] }<>-> 1 which is true. Oops!
//
// We therefore use the following rules instead:
// b[->min..max] == (!b)[*];b;b[->min-1..max-1]
// b[->0..max] == [*0] | (!b)[*];b;b[->min-1..max-1]
formula* f1 = // (!b)[*]
bunop::instance(bunop::Star,
unop::instance(unop::Not,
bo->child()->clone()),
0, bunop::unbounded);
formula* f2 = // b;b[->min-1..max-1]
multop::instance(multop::Concat,
bo->child()->clone(),
bunop::instance(op,
bo->child()->clone(),
min2, max2));
f = multop::instance(multop::Concat, f1, f2);
res_ = recurse_and_concat(f);
f->destroy();
if (min == 0)
res_ |= now_to_concat();
return;
}
}
/* Unreachable code. */
assert(0);