ENH: unified some common parser static methods

COMP: delay evaluation of fieldToken enumeration types

- lazy evaluation at runTime instead of compile-time to make the code
  independent of initialization order.
  Otherwise triggers problems on gcc-4.8.5 on some systems where
  glibc is the same age, or older.

applications/test/parserInfo/Test-parserInfo.C

@@ -0,0 +1,131 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2019 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/>.
+
+Description
+    Output some (expressions) parser information
+
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "IOstreams.H"
+#include "List.H"
+#include "fieldExprParser.H"
+#include "patchExprParser.H"
+#include "volumeExprParser.H"
+
+using namespace Foam;
+
+template<class Parser>
+void printInformation
+(
+    Ostream& os,
+    const word& name,
+    const bool printNames,
+    const bool printRules
+)
+{
+    if (printNames)
+    {
+        os << nl << name << " tokenNames:" << nl;
+        Parser::printTokenNames(os);
+    }
+
+    if (printRules)
+    {
+        os << nl << name << " rules:" << nl;
+        Parser::printRules(os);
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    argList::noBanner();
+    argList::addNote
+    (
+        "Display token names or rules for specified expression parser(s)."
+        " Without options, displays everything."
+    );
+
+    argList::addBoolOption("rules", "Print parser rules");
+    argList::addBoolOption("tokens", "Print token names");
+
+    argList::addBoolOption("field", "Field expression parser");
+    argList::addBoolOption("patch", "Patch expression parser");
+    argList::addBoolOption("volume", "Volume expression parser");
+
+    argList args(argc, argv);
+
+    // Defaults
+    const bool all = !args.count({"field", "patch", "volume"});
+    const bool both = !args.count({"tokens", "rules"});
+
+    const bool printNames = both || args.found("tokens");
+    const bool printRules = both || args.found("rules");
+
+
+    if (all || args.found("field"))
+    {
+        printInformation<Foam::expressions::fieldExpr::parser>
+        (
+            Info,
+            "field",
+            printNames,
+            printRules
+        );
+    }
+
+    if (all || args.found("patch"))
+    {
+        printInformation<Foam::expressions::patchExpr::parser>
+        (
+            Info,
+            "patch",
+            printNames,
+            printRules
+        );
+    }
+
+    if (all || args.found("volume"))
+    {
+        printInformation<Foam::expressions::volumeExpr::parser>
+        (
+            Info,
+            "volume",
+            printNames,
+            printRules
+        );
+    }
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //