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Handling negations introduced by “forall” elimination correctly.

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This commit is contained in:
Patrick Lühne 2017-06-27 11:35:47 +02:00
parent 729ecc9475
commit d451d2d548
Signed by: patrick
GPG Key ID: 05F3611E97A70ABF
1 changed files with 2 additions and 64 deletions
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66
lib/pddlparse/src/pddlparse/detail/normalization/Reduction.cpp
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@ -269,78 +269,16 @@ void eliminateForAll(ast::Precondition &precondition)
////////////////////////////////////////////////////////////////////////////////////////////////////
void eliminateDoubleNegations(ast::Precondition &precondition)
{
const auto handleAtomicFormula =
[](ast::AtomicFormula &)
{
};
const auto handleAnd =
[](ast::AndPointer<ast::Precondition> &and_)
{
for (auto &argument : and_->arguments)
eliminateDoubleNegations(argument);
};
const auto handleExists =
[](ast::ExistsPointer<ast::Precondition> &exists)
{
eliminateDoubleNegations(exists->argument);
};
const auto handleForAll =
[&](ast::ForAllPointer<ast::Precondition> &forAll)
{
eliminateDoubleNegations(forAll->argument);
};
const auto handleImply =
[&](ast::ImplyPointer<ast::Precondition> &imply)
{
eliminateDoubleNegations(imply->argumentLeft);
eliminateDoubleNegations(imply->argumentRight);
};
const auto handleNot =
[&](ast::NotPointer<ast::Precondition> &not_)
{
eliminateDoubleNegations(not_->argument);
if (not_->argument.is<ast::NotPointer<ast::Precondition>>())
{
// As the parent contains the argument, the argument needs to be saved before overwriting the parent
// TODO: check whether this workaround can be avoided
auto argument = std::move(not_->argument.get<ast::NotPointer<ast::Precondition>>());
precondition = std::move(argument);
}
};
const auto handleOr =
[](ast::OrPointer<ast::Precondition> &or_)
{
for (auto &argument : or_->arguments)
eliminateDoubleNegations(argument);
};
precondition.match(handleAtomicFormula, handleAnd, handleExists, handleForAll, handleImply, handleNot, handleOr);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
void reduce(ast::Precondition &precondition)
{
// Replace “imply” statements with disjunctions
eliminateImply(precondition);
// Negation-normalize the precondition
negationNormalize(precondition);
// Eliminate “forall” statements
eliminateForAll(precondition);
// Eliminate double negations introduced by eliminating “forall” statements
eliminateDoubleNegations(precondition);
// Negation-normalize the precondition
negationNormalize(precondition);
}
////////////////////////////////////////////////////////////////////////////////////////////////////