Patrick Lühne
c294a29cb2
This adds support for declaring predicates as placeholders through the
“#external” directive in the input language of clingo.
Placeholders are not subject to completion. This prevents predicates
that represent instance-specific facts from being assumed as universally
false by default negation when translating an encoding.
This stretches clingo’s usual syntax a bit to make the implementation
lightweight. In order to declare a predicate with a specific arity as a
placeholder, the following statement needs to be added to the program:
#external <predicate name>(<arity>).
Multiple unit tests cover cases where placeholders are used or not as
well as a more complex graph coloring example.
52 lines
1.2 KiB
C++
52 lines
1.2 KiB
C++
#ifndef __ANTHEM__CONTEXT_H
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#define __ANTHEM__CONTEXT_H
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#include <optional>
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#include <anthem/AST.h>
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#include <anthem/output/Logger.h>
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#include <anthem/output/ParenthesisStyle.h>
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namespace anthem
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{
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////////////////////////////////////////////////////////////////////////////////////////////////////
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//
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// Context
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//
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////////////////////////////////////////////////////////////////////////////////////////////////////
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struct PredicateSignatureMeta
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{
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ast::PredicateSignature predicateSignature;
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bool used{false};
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};
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////////////////////////////////////////////////////////////////////////////////////////////////////
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struct Context
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{
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Context() = default;
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explicit Context(output::Logger &&logger)
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: logger{std::move(logger)}
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{
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}
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output::Logger logger;
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bool performSimplification = false;
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bool performCompletion = false;
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std::optional<std::vector<PredicateSignatureMeta>> visiblePredicateSignatures;
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std::optional<std::vector<PredicateSignatureMeta>> externalPredicateSignatures;
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ast::ParenthesisStyle parenthesisStyle = ast::ParenthesisStyle::Normal;
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};
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////////////////////////////////////////////////////////////////////////////////////////////////////
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}
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#endif
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