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simplifier: new PSL simplifications

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{e[*0..j]}<>->f = {e[*1..j]}<>->f
{e[*0..j]}[]->f = {e[*1..j]}[]->f

Fixes #81.

This required a small change to the bounded-star-normal-form to prevent
infinite recursion.

* spot/tl/simplify.cc: Implement these rules.
* doc/tl/tl.tex, NEWS: Document them.
* tests/core/reduccmp.test: Add tests, and adjust others.
* tests/core/unambig.test: Replace formula that used to generated an
ambiguous automaton, but now generates a deterministic one.
This commit is contained in:
Alexandre Duret-Lutz 2016-07-19 16:40:59 +02:00
parent d5b2de7fa8
commit abff7eba8e
5 changed files with 38 additions and 16 deletions
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29
spot/tl/simplify.cc
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@ -1290,14 +1290,20 @@ namespace spot
return f;
case op::Star:
{
if (!f.accepts_eword())
return f;
formula h = f[0];
auto min = f.min();
if (h.accepts_eword())
min = 0;
if (min == 0)
h = f.max() == formula::unbounded()
? c_->star_normal_form(h)
: c_->star_normal_form_bounded(h);
auto min = 0;
if (f.max() == formula::unbounded())
{
h = c_->star_normal_form(h);
}
else
{
h = c_->star_normal_form_bounded(h);
if (h.accepts_eword())
min = 1;
}
return formula::Star(h, min, f.max());
}
}
@ -1359,12 +1365,19 @@ namespace spot
// b W !s
return recurse(formula::binop(op_w, b, ns));
}
// {s[*0..j]}[]->b = {s[*1..j]}[]->b
// {s[*0..j]}<>->b = {s[*1..j]}<>->b
if (min == 0)
return recurse(formula::binop(bindop,
formula::Star(s, 1, max), b));
if (opt_.reduce_size_strictly)
return orig;
// {s[*i..j]}[]->b = {s;s;...;s[*1..j-i+1]}[]->b
// = {s}[]->X({s}[]->X(...[]->X({s[*1..j-i+1]}[]->b)))
// if i>0 and s does not accept the empty word
if (min == 0 || s.accepts_eword())
assert(min > 0);
if (s.accepts_eword())
return orig;
--min;
if (max != formula::unbounded())