141 lines
4.3 KiB
C++
141 lines
4.3 KiB
C++
#ifndef __ANTHEM__STATEMENT_VISITOR_H
|
||
#define __ANTHEM__STATEMENT_VISITOR_H
|
||
|
||
#include <anthem/AST.h>
|
||
#include <anthem/Body.h>
|
||
#include <anthem/Head.h>
|
||
#include <anthem/Term.h>
|
||
#include <anthem/Utils.h>
|
||
|
||
namespace anthem
|
||
{
|
||
|
||
////////////////////////////////////////////////////////////////////////////////////////////////////
|
||
//
|
||
// StatementVisitor
|
||
//
|
||
////////////////////////////////////////////////////////////////////////////////////////////////////
|
||
|
||
struct StatementVisitor
|
||
{
|
||
std::vector<ast::Formula> visit(const Clingo::AST::Program &program, const Clingo::AST::Statement &statement, Context &context)
|
||
{
|
||
// TODO: refactor
|
||
context.logger.log(output::Priority::Debug, (std::string("[program] ") + program.name).c_str());
|
||
|
||
if (!program.parameters.empty())
|
||
throwErrorAtLocation(statement.location, "program parameters currently unsupported", context);
|
||
|
||
return {};
|
||
}
|
||
|
||
std::vector<ast::Formula> visit(const Clingo::AST::Rule &rule, const Clingo::AST::Statement &, Context &context)
|
||
{
|
||
context.reset();
|
||
|
||
// Concatenate all head terms
|
||
rule.head.data.accept(HeadLiteralCollectFunctionTermsVisitor(), rule.head, context);
|
||
|
||
ast::And antecedent;
|
||
|
||
// Compute consequent
|
||
auto consequent = rule.head.data.accept(HeadLiteralTranslateToConsequentVisitor(), rule.head, context);
|
||
|
||
if (!consequent)
|
||
{
|
||
context.logger.log(output::Priority::Error, "could not translate formula consequent");
|
||
return {};
|
||
}
|
||
|
||
// Generate auxiliary variables replacing the head atom’s arguments
|
||
for (auto i = context.headTerms.cbegin(); i != context.headTerms.cend(); i++)
|
||
{
|
||
const auto &headTerm = **i;
|
||
|
||
auto variableName = std::string(AuxiliaryHeadVariablePrefix) + std::to_string(i - context.headTerms.cbegin() + 1);
|
||
auto element = ast::Variable(std::move(variableName), ast::Variable::Type::Reserved);
|
||
auto set = translate(headTerm, context);
|
||
auto in = ast::In(std::move(element), std::move(set));
|
||
|
||
antecedent.arguments.emplace_back(std::move(in));
|
||
}
|
||
|
||
// Translate body literals
|
||
for (auto i = rule.body.cbegin(); i != rule.body.cend(); i++)
|
||
{
|
||
const auto &bodyLiteral = *i;
|
||
|
||
auto argument = bodyLiteral.data.accept(BodyBodyLiteralTranslateVisitor(), bodyLiteral, context);
|
||
|
||
if (!argument)
|
||
throwErrorAtLocation(bodyLiteral.location, "could not translate body literal", context);
|
||
|
||
antecedent.arguments.emplace_back(std::move(argument.value()));
|
||
}
|
||
|
||
std::vector<ast::Formula> formulas;
|
||
|
||
if (!context.isChoiceRule)
|
||
formulas.emplace_back(ast::Formula::make<ast::Implies>(std::move(antecedent), std::move(consequent.value())));
|
||
else
|
||
{
|
||
const auto createFormula =
|
||
[&](ast::Formula &argument, bool isLastOne)
|
||
{
|
||
auto consequent = std::move(argument);
|
||
|
||
if (!isLastOne)
|
||
formulas.emplace_back(ast::Formula::make<ast::Implies>(ast::deepCopy(antecedent), std::move(consequent)));
|
||
else
|
||
formulas.emplace_back(ast::Formula::make<ast::Implies>(std::move(antecedent), std::move(consequent)));
|
||
|
||
auto &implies = formulas.back().get<ast::Implies>();
|
||
auto &antecedent = implies.antecedent.get<ast::And>();
|
||
antecedent.arguments.emplace_back(ast::deepCopy(implies.consequent));
|
||
};
|
||
|
||
if (consequent.value().is<ast::Or>())
|
||
{
|
||
auto &disjunction = consequent.value().get<ast::Or>();
|
||
|
||
for (auto &argument : disjunction.arguments)
|
||
createFormula(argument, &argument == &disjunction.arguments.back());
|
||
}
|
||
// TODO: check whether this is really correct for all possible consequent types
|
||
else
|
||
createFormula(consequent.value(), true);
|
||
}
|
||
|
||
for (auto &formula : formulas)
|
||
{
|
||
auto &implies = formula.get<ast::Implies>();
|
||
auto &antecedent = implies.antecedent.get<ast::And>();
|
||
|
||
// Use “true” as the consequent in case it is empty
|
||
if (antecedent.arguments.empty())
|
||
implies.antecedent = ast::Formula::make<ast::Boolean>(true);
|
||
else if (antecedent.arguments.size() == 1)
|
||
{
|
||
// TODO: remove workaround
|
||
auto tmp = std::move(antecedent.arguments[0]);
|
||
implies.antecedent = std::move(tmp);
|
||
}
|
||
}
|
||
|
||
return formulas;
|
||
}
|
||
|
||
template<class T>
|
||
std::vector<ast::Formula> visit(const T &, const Clingo::AST::Statement &statement, Context &context)
|
||
{
|
||
throwErrorAtLocation(statement.location, "statement currently unsupported, expected rule", context);
|
||
return {};
|
||
}
|
||
};
|
||
|
||
////////////////////////////////////////////////////////////////////////////////////////////////////
|
||
|
||
}
|
||
|
||
#endif
|