ENH: expression versions of Function1 and PatchFunction1 (#1709)

src/OpenFOAM/expressions/Function1/Function1Expression.H

@@ -0,0 +1,165 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2020 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
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    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::Function1Types::Function1Expression
+
+Description
+    Function1 with values supplied by a parsed expression.
+
+Usage
+    Example:
+    \verbatim
+    <patchName>
+    {
+        type            uniformFixedValue;
+        uniformValue
+        {
+            type            expression;
+
+            // optional variables for use within the expression
+            variables
+            (
+                "start = 0.5"
+                "stop  = 1"
+            );
+
+            // A step function
+            expression
+            #{
+                mag(arg() > start && arg() < stop) * vector(1, 0, 0)
+            #};
+        }
+    }
+    \endverbatim
+
+Very much like '#eval' but runtime
+
+See also
+    Foam::exprFixedValueFvPatchField
+
+SourceFiles
+    Function1Expression.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Function1Types_expression_H
+#define Function1Types_expression_H
+
+#include "Function1.H"
+#include "fieldExprDriver.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace Function1Types
+{
+
+/*---------------------------------------------------------------------------*\
+                     Class Function1Expression Declaration
+\*---------------------------------------------------------------------------*/
+
+template<class Type>
+class Function1Expression
+:
+    public Function1<Type>
+{
+    // Private Data
+
+        //- Dictionary contents for the function
+        const dictionary dict_;
+
+        //- The expression
+        expressions::exprString valueExpr_;
+
+        //- The expression driver
+        mutable expressions::fieldExprDriver driver_;
+
+
+    // Private Member Functions
+
+        //- No copy assignment
+        void operator=(const Function1Expression<Type>&) = delete;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("expression");
+
+
+    // Constructors
+
+        //- Construct from patch, entry name and dictionary
+        //  The patch must correspond to an fvPatch!
+        Function1Expression
+        (
+            const word& entryName,
+            const dictionary& dict
+        );
+
+        //- Copy construct
+        explicit Function1Expression(const Function1Expression<Type>& rhs);
+
+
+    //- Destructor
+    virtual ~Function1Expression() = default;
+
+
+    // Member Functions
+
+        //- Return value.
+        //  The parameter 'x' is accessible as 'arg' in the function
+        virtual Type value(const scalar x) const;
+
+        //- Integrate between two values
+        virtual Type integrate
+        (
+            const scalar x1,
+            const scalar x2
+        ) const;
+
+        //- Write in dictionary format
+        virtual void writeData(Ostream& os) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Function1Types
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#ifdef NoRepository
+    #include "Function1Expression.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //