exprTraits.H

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    Copyright (C) 2021 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::exprTypeTraits
 
Description
    Simple type identifiers for polymorphic expression values.
 
    The definitions are similar to std::integral_constant in that they
    provide value, value_type (and name).
 
\*---------------------------------------------------------------------------*/
 
#ifndef expressions_exprTraits_H
#define expressions_exprTraits_H
 
// Regular field types
#include "label.H"
#include "scalar.H"
#include "vector.H"
#include "sphericalTensor.H"
#include "symmTensor.H"
#include "tensor.H"
#include "word.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace expressions
{
 
//- An enumeration of known and expected expression value types.
//  Do not rely on the enumeration values for any direct coding.
//
//  \note NONE use used when initializing types, whereas INVALID is used
//  for unsupported types (never as a stored type).
//  This avoids false positives when testing.
//
//  Except NONE and INVALID, the enumerations will mostly not be used
//  directly, but through exprTypeTraits :: value
 
enum class valueTypeCode : unsigned char
{
    NONE = 0,               
    INVALID,                
 
    // Rank 0 types
    type_bool,              
    type_label,             
    type_scalar,            
 
    // Rank 1 types
    type_vector,            
 
    // Rank 2 types
    type_sphericalTensor,   
    type_symmTensor,        
    type_tensor             
};
 
 
// Global Functions
 
//- From string to valueTypeCode (if any)
valueTypeCode valueTypeCodeOf(const word& dataTypeName);
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace expressions
 
 
/*---------------------------------------------------------------------------*\
                       Class exprTypeTraits Declaration
\*---------------------------------------------------------------------------*/
 
// Generic enumerated traits is INVALID (unknown)
template<class Type>
struct exprTypeTraits
{
    typedef Type value_type;
    static constexpr const char* const name = "";
    static constexpr
        ::Foam::expressions::valueTypeCode value =
        ::Foam::expressions::valueTypeCode::INVALID;
};
 
 
#undef  defineExprTypeTraits
#define defineExprTypeTraits(Type, Name)                                      \
    template<>                                                                \
    struct exprTypeTraits<Type>                                               \
    {                                                                         \
        typedef Type value_type;                                              \
        static constexpr const char* const name = #Name;                      \
        static constexpr                                                      \
            ::Foam::expressions::valueTypeCode value =                        \
            ::Foam::expressions::valueTypeCode::type_##Name;                  \
    };
 
 
// Define with "name" to match regular pTraits typeName
defineExprTypeTraits(bool, bool);
defineExprTypeTraits(::Foam::label, label);
defineExprTypeTraits(::Foam::scalar, scalar);
defineExprTypeTraits(::Foam::vector, vector);
defineExprTypeTraits(::Foam::tensor, tensor);
defineExprTypeTraits(::Foam::sphericalTensor, sphericalTensor);
defineExprTypeTraits(::Foam::symmTensor, symmTensor);
 
#undef defineExprTypeTraits
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
//- A word representation of a valueTypeCode. Empty for INVALID
word name(const expressions::valueTypeCode typeCode);
 
 
//- A word representation of a valueTypeCode. Empty for INVALID
template<>
struct nameOp<expressions::valueTypeCode>
{
    word operator()(const expressions::valueTypeCode typeCode) const
    {
        return Foam::name(typeCode);
    }
};
 
// No IOstream Operators for valueTypeCode at the moment (Nov 2021)
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //