| Metafunction Is Returns whether a concept is fulfilled. Is<TConcept>::Type Is<TConcept>::VALUE Include Headers seqan/basic.h Parameters
TConcept | A concept that is specialized with type(s) that should be tested for fulfilling the concept.
Remarks The Is-metafunction can be used to test types for fulfilling a concept without causing compilation errors. If True/true is returned, TConcept must pass the concept test via SEQAN_CONCEPT_ASSERT. It can be used to switch between different implementations depending on the concept of a type, or in combination with SEQAN_FUNC_ENABLE_IF to make a function only visible to types of certain concepts. Return Values True/true if TConcept is a fulfilled concept, otherwise False/false. Examples Is<SequenceConcept<TSeq> >::Type IfC<Is<ContainerConcept<TSeq> >::VALUE, T1, T2>::Type std::cout << Is<IntegerConcept<int> >::VALUE << std::endl; // 1 std::cout << Is<IntegerConcept<double> >::VALUE << std::endl; // 0 Define a hierarchy of concepts and two models Alice and Bob that implements some of them. Is determines which concepts are explicitly or implicitly fulfilled. struct Alice {}; struct Bob {}; SEQAN_CONCEPT(ConceptA, (T)) {}; SEQAN_CONCEPT(ConceptB, (T)) {}; SEQAN_CONCEPT_REFINE(ConceptC, (T), (ConceptA)(ConceptB)) {}; SEQAN_CONCEPT_REFINE(ConceptD, (T), (ConceptC)) {}; SEQAN_CONCEPT_IMPL(Alice, (ConceptA)(ConceptB)); SEQAN_CONCEPT_IMPL(Bob, (ConceptC)); std::cout << Is< ConceptA<Alice> >::VALUE << std::endl; // 1 std::cout << Is< ConceptB<Alice> >::VALUE << std::endl; // 1 std::cout << Is< ConceptC<Alice> >::VALUE << std::endl; // 0 std::cout << Is< ConceptD<Alice> >::VALUE << std::endl; // 0 std::cout << Is< ConceptA<Bob> >::VALUE << std::endl; // 1 std::cout << Is< ConceptB<Bob> >::VALUE << std::endl; // 1 std::cout << Is< ConceptC<Bob> >::VALUE << std::endl; // 1 std::cout << Is< ConceptD<Bob> >::VALUE << std::endl; // 0 See Also SEQAN_CONCEPT_ASSERT, SEQAN_FUNC_ENABLE_IF SeqAn - Sequence Analysis Library - www.seqan.de

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