dictionary::functionEntries::negEntry: new function to negate a dictionary variable

E.g. in a velocity field file:

    Umean 5.75;
    .
    .
    .
    inlet
    {
        type            uniformFixedValue;
        uniformValue    (#neg $Umean 0 0);
    }

src/OpenFOAM/Make/files

@@ -210,6 +210,7 @@ $(dictionaryListEntry)/dictionaryListEntry.C
 $(dictionaryListEntry)/dictionaryListEntryIO.C
 
 functionEntries = $(dictionary)/functionEntries
+$(functionEntries)/negEntry/negEntry.C
 $(functionEntries)/calcEntry/calcEntry.C
 $(functionEntries)/codeStream/codeStream.C
 $(functionEntries)/functionEntry/functionEntry.C

src/OpenFOAM/db/dictionary/functionEntries/negEntry/negEntry.C

@@ -0,0 +1,137 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2018 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "negEntry.H"
+#include "addToMemberFunctionSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionEntries
+{
+    defineTypeNameAndDebug(negEntry, 0);
+
+    addToMemberFunctionSelectionTable
+    (
+        functionEntry,
+        negEntry,
+        execute,
+        dictionaryIstream
+    );
+
+    addToMemberFunctionSelectionTable
+    (
+        functionEntry,
+        negEntry,
+        execute,
+        primitiveEntryIstream
+    );
+}
+}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+Foam::string Foam::functionEntries::negEntry::negateVariable
+(
+    const dictionary& parentDict,
+    Istream& is
+)
+{
+    // Read variable name as a word including the '$'
+    const word varWord(is);
+
+    if (varWord[0] != '$')
+    {
+        FatalIOErrorInFunction
+        (
+            parentDict
+        )   << "Expected variable name beginning with a '$' but found '"
+            << varWord << "'" << exit(FatalIOError);
+
+        return string::null;
+    }
+
+    // Strip the leading '$' from the variable name
+    const string varName = varWord(1, varWord.size()-1);
+
+    // Lookup the variable name in the parent dictionary....
+    const entry* ePtr = parentDict.lookupScopedEntryPtr(varName, true, false);
+
+    if (ePtr && ePtr->isStream())
+    {
+        const token variable(ePtr->stream());
+
+        // Negate variable
+        OStringStream os(is.format());
+        os << '-' << variable;
+
+        return os.str();
+    }
+    else
+    {
+        FatalIOErrorInFunction
+        (
+            parentDict
+        )   << "Illegal dictionary variable name " << varName << endl
+            << "Valid dictionary entries are " << parentDict.toc()
+            << exit(FatalIOError);
+
+        return string::null;
+    }
+}
+
+
+bool Foam::functionEntries::negEntry::execute
+(
+    const dictionary& parentDict,
+    primitiveEntry& thisEntry,
+    Istream& is
+)
+{
+    // Reinsert negated variable into entry
+    IStringStream resultStream(negateVariable(parentDict, is));
+    thisEntry.read(parentDict, resultStream);
+
+    return true;
+}
+
+
+bool Foam::functionEntries::negEntry::execute
+(
+    dictionary& parentDict,
+    Istream& is
+)
+{
+    // Reinsert negated variable into dictionary
+    IStringStream resultStream(negateVariable(parentDict, is));
+    parentDict.read(resultStream);
+
+    return true;
+}
+
+
+// ************************************************************************* //

src/OpenFOAM/db/dictionary/functionEntries/negEntry/negEntry.H

@@ -0,0 +1,115 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2018 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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::functionEntries::negEntry
+
+Description
+    Negate a dictionary variable by prefixing with \c #neg
+
+    E.g.
+    \verbatim
+        Umean 5.75;
+        .
+        .
+        .
+        inlet
+        {
+            type            uniformFixedValue;
+            uniformValue    (#neg $Umean 0 0);
+        }
+    \endverbatim
+    Note the space required between the \c #neg and the '$'
+
+SourceFiles
+    negEntry.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef negEntry_H
+#define negEntry_H
+
+#include "functionEntry.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionEntries
+{
+
+/*---------------------------------------------------------------------------*\
+                         Class negEntry Declaration
+\*---------------------------------------------------------------------------*/
+
+class negEntry
+:
+    public functionEntry
+{
+    // Private Member Functions
+
+        //- Lookup variable, negate and return as a string
+        static string negateVariable
+        (
+            const dictionary& parentDict,
+            Istream& is
+        );
+
+        //- Disallow default bitwise copy construct
+        negEntry(const negEntry&);
+
+        //- Disallow default bitwise assignment
+        void operator=(const negEntry&);
+
+
+public:
+
+    //- Runtime type information
+    ClassName("neg");
+
+
+    // Member Functions
+
+        //- Execute the functionEntry in a sub-dict context
+        static bool execute(dictionary& parentDict, Istream&);
+
+        //- Execute the functionEntry in a primitiveEntry context
+        static bool execute
+        (
+            const dictionary& parentDict,
+            primitiveEntry&,
+            Istream&
+        );
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace functionEntries
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //