ENH: improved separation of scanner/parser debug selection

- now use debug 2 for scanner and debug 4 for parser.
  Provided better feedback about what is being parsed (debug mode)

- relocate debug application to applications/tools/foamExprParserInfo

applications/tools/foamExprParserInfo/Make/files

@@ -0,0 +1,3 @@
+foamExprParserInfo.C
+
+EXE = $(FOAM_APPBIN)/foamExprParserInfo

applications/tools/foamExprParserInfo/Make/options

@@ -0,0 +1,7 @@
+EXE_INC = \
+    -I$(LIB_SRC)/finiteVolume/lnInclude \
+    -I$(LIB_SRC)/meshTools/lnInclude
+
+EXE_LIBS = \
+    -lfiniteVolume \
+    -lmeshTools

applications/tools/foamExprParserInfo/foamExprParserInfo.C

@@ -0,0 +1,199 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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/>.
+
+Application
+    foamExprParserInfo
+
+Group
+    grpTools
+
+Description
+    Display token names or rules for specified expression parsers.
+
+    In the Lemon grammar, terminals (uppercase) are listed first.
+    Non-terminals (lowercase) are listed second.
+
+    The current OpenFOAM grammar short naming conventions:
+    - svalue : scalar value
+    - sfield : scalar field
+    - lfield : logic field
+    - vfield : vector field
+    - tfield : tensor field
+    - hfield : sphericalTensor field
+    - yfield : symmTensor field
+    .
+    Prefixes: 's' (surface) or 'p' (point).
+    For example, psfield for a point scalar field
+
+Usage
+    \b foamExprParserInfo [OPTION]
+
+    Options:
+      - \par -rules
+        Print parser rules
+
+      - \par -tokens
+        Print token names (default)
+
+      - \par -all
+        Display information for all parsers
+
+      - \par -field
+        Field expression parser information
+
+      - \par -patch
+        Patch expression parser information
+
+      - \par -volume
+        Volume expression 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 << "# Tokens for " << name << nl;
+        Parser::printTokenNames(os);
+    }
+
+    if (printRules)
+    {
+        os << nl << "# Rules for " << name << nl;
+        Parser::printRules(os);
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    argList::noBanner();
+    argList::noParallel();
+    argList::setAdvanced("case");  // Hide -case : has no meaning here
+
+    argList::addNote
+    (
+        "Display token names or rules for specified expression parsers.\n"
+        "In the Lemon grammar, terminals (uppercase) are listed first.\n"
+        "Non-terminals (lowercase) are listed second.\n \n"
+        "The current OpenFOAM grammar short naming conventions:\n"
+        "  * svalue : scalar value\n"
+        "  * sfield : scalar field\n"
+        "  * lfield : logic field\n"
+        "  * vfield : vector field\n"
+        "  * tfield : tensor field\n"
+        "  * hfield : sphericalTensor field\n"
+        "  * yfield : symmTensor field\n"
+        " \n"
+        "Prefixes: 's' (surface) or 'p' (point).\n"
+        "Eg, psfield for a point scalar field\n"
+    );
+
+    argList::addBoolOption("rules", "Print parser rules");
+    argList::addBoolOption("tokens", "Print token names (default)");
+
+    argList::addBoolOption("all", "Display information for all parsers");
+    argList::addBoolOption("field", "Field expression parser information");
+    argList::addBoolOption("patch", "Patch expression parser information");
+    argList::addBoolOption("volume", "Volume expression parser information");
+
+    argList args(argc, argv);
+
+    const bool all = args.found("all");
+    const bool printRules = args.found("rules");
+    const bool printNames = args.found("tokens") || !printRules;
+
+    label count = 0;
+
+    if (all || args.found("field"))
+    {
+        ++count;
+        printInformation<expressions::fieldExpr::parser>
+        (
+            Info,
+            "field",
+            printNames,
+            printRules
+        );
+    }
+
+    if (all || args.found("patch"))
+    {
+        ++count;
+        printInformation<expressions::patchExpr::parser>
+        (
+            Info,
+            "patch",
+            printNames,
+            printRules
+        );
+    }
+
+    if (all || args.found("volume"))
+    {
+        ++count;
+        printInformation<expressions::volumeExpr::parser>
+        (
+            Info,
+            "volume",
+            printNames,
+            printRules
+        );
+    }
+
+    if (!count)
+    {
+        InfoErr
+            << "Error: no parser selected." << nl
+            << "See '" << args.executable() << " -help' for usage" << nl
+            << nl;
+
+        return 1;
+    }
+
+    return 0;
+}
+
+
+// ************************************************************************* //