diff --git a/applications/test/predicates/Make/files b/applications/test/predicates/Make/files
new file mode 100644
index 0000000000..6197f71dfa
--- /dev/null
+++ b/applications/test/predicates/Make/files
@@ -0,0 +1,3 @@
+Test-predicates.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-predicates
diff --git a/applications/test/predicates/Make/options b/applications/test/predicates/Make/options
new file mode 100644
index 0000000000..9d6f459ad8
--- /dev/null
+++ b/applications/test/predicates/Make/options
@@ -0,0 +1 @@
+/**/
diff --git a/applications/test/predicates/Test-predicates.C b/applications/test/predicates/Test-predicates.C
new file mode 100644
index 0000000000..9b9e77ddbb
--- /dev/null
+++ b/applications/test/predicates/Test-predicates.C
@@ -0,0 +1,112 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     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/>.
+
+Application
+    Test-predicates
+
+Description
+    Simple tests using predicates
+
+\*---------------------------------------------------------------------------*/
+
+#include "IOstreams.H"
+#include "labelList.H"
+#include "wordList.H"
+#include "predicates.H"
+#include "FlatOutput.H"
+#include "regExp.H"
+
+using namespace Foam;
+
+
+template<class ListType, class UnaryPredicate>
+label printMatching(const ListType& list, const UnaryPredicate& pred)
+{
+    label count = 0;
+
+    Info<< "(";
+
+    for (const auto& val : list)
+    {
+        if (pred(val))
+        {
+            if (count) Info<< ' ';
+            Info<< val;
+            ++count;
+        }
+    }
+
+    Info<< ") => " << count << nl;
+
+    return count;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+//  Main program:
+
+int main(int argc, char *argv[])
+{
+    wordList words
+    {
+        "abc",
+        "def",
+        "hij",
+        "abc_",
+        "def_",
+        "hij_",
+    };
+
+    labelRange range(-10, 40);
+    labelList values(range.begin(), range.end());
+
+    Info<<"words:  " << flatOutput(words) << endl;
+    Info<<"values: " << flatOutput(values)  << endl;
+
+    regExp matcher(".*_.*");
+
+    Info<<"With '_': ";
+    printMatching(words, matcher);
+
+    Info<<"All: ";
+    printMatching(words, predicates::always());
+
+    Info<<"None: ";
+    printMatching(words, predicates::never());
+
+    Info<<"Neg values: ";
+    printMatching(values, [](const label v) { return v < 0; });
+
+    Info<<"Even values: ";
+    printMatching(values, [](const label v) { return !(v % 2); });
+
+    Info<<"All: ";
+    printMatching(values, predicates::always());
+
+    Info<<"None: ";
+    printMatching(values, predicates::never());
+
+    return 0;
+}
+
+// ************************************************************************* //
diff --git a/applications/test/wordRe/Test-wordRe.C b/applications/test/wordRe/Test-wordRe.C
index f3ab4a3719..be1af08a54 100644
--- a/applications/test/wordRe/Test-wordRe.C
+++ b/applications/test/wordRe/Test-wordRe.C
@@ -33,6 +33,7 @@ Description
 #include "keyType.H"
 #include "wordRe.H"
 #include "wordRes.H"
+#include "predicates.H"
 
 using namespace Foam;
 
@@ -62,6 +63,7 @@ int main(int argc, char *argv[])
     Info<< "match xyz: "  << wrelist("xyz") << endl;
     Info<< "match zyx: "  << wrelist("zyx") << endl;
     Info<< "match xyz: "  << wrelist.match("xyz") << endl;
+    Info<< "match any: "  << predicates::always()("any junk") << endl;
     Info<< "keyre match: "  << keyre("xyz") << endl;
     Info<< "string match: "  << string("this").match("xyz") << endl;
     Info<< "string match: "  << string("x.*")("xyz") << endl;
diff --git a/src/OpenFOAM/primitives/bools/Switch/Switch.H b/src/OpenFOAM/primitives/bools/Switch/Switch.H
index 25b79905ac..63ef5ead52 100644
--- a/src/OpenFOAM/primitives/bools/Switch/Switch.H
+++ b/src/OpenFOAM/primitives/bools/Switch/Switch.H
@@ -50,8 +50,8 @@ namespace Foam
 class Switch;
 class dictionary;
 
-Istream& operator>>(Istream&, Switch&);
-Ostream& operator<<(Ostream&, const Switch&);
+Istream& operator>>(Istream& is, Switch& s);
+Ostream& operator<<(Ostream& is, const Switch& s);
 
 
 /*---------------------------------------------------------------------------*\
@@ -108,8 +108,12 @@ private:
 
     // Static Member Functions
 
-        //- Return a switchType representation of a word
-        static switchType asEnum(const std::string&, const bool allowInvalid);
+        //- Return a switchType representation of an input string
+        static switchType asEnum
+        (
+            const std::string& str,
+            const bool allowInvalid
+        );
 
 
 public:
@@ -161,8 +165,8 @@ public:
         //  value is not found, it is added into the dictionary.
         static Switch lookupOrAddToDict
         (
-            const word&,
-            dictionary&,
+            const word& name,
+            dictionary& dict,
             const Switch& defaultValue = false
         );
 
@@ -176,7 +180,7 @@ public:
         const char* asText() const;
 
         //- Update the value of the Switch if it is found in the dictionary
-        bool readIfPresent(const word&, const dictionary&);
+        bool readIfPresent(const word& name, const dictionary& dict);
 
 
     // Member Operators
@@ -202,8 +206,8 @@ public:
 
     // IOstream Operators
 
-        friend Istream& operator>>(Istream&, Switch&);
-        friend Ostream& operator<<(Ostream&, const Switch&);
+        friend Istream& operator>>(Istream& is, Switch& s);
+        friend Ostream& operator<<(Ostream& os, const Switch& s);
 };
 
 
diff --git a/src/OpenFOAM/primitives/bools/Switch/SwitchIO.C b/src/OpenFOAM/primitives/bools/Switch/SwitchIO.C
index e716820d5f..b0bda84beb 100644
--- a/src/OpenFOAM/primitives/bools/Switch/SwitchIO.C
+++ b/src/OpenFOAM/primitives/bools/Switch/SwitchIO.C
@@ -79,10 +79,7 @@ Foam::Istream& Foam::operator>>(Istream& is, Switch& s)
         return is;
     }
 
-
-    // Check state of Istream
-    is.check("Istream& operator>>(Istream&, Switch&)");
-
+    is.check(FUNCTION_NAME);
     return is;
 }
 
@@ -90,7 +87,7 @@ Foam::Istream& Foam::operator>>(Istream& is, Switch& s)
 Foam::Ostream& Foam::operator<<(Ostream& os, const Switch& s)
 {
     os << Switch::names[s.switch_];
-    os.check("Ostream& operator<<(Ostream&, const Switch&)");
+    os.check(FUNCTION_NAME);
     return os;
 }
 
diff --git a/src/OpenFOAM/primitives/bools/bool/bool.H b/src/OpenFOAM/primitives/bools/bool/bool.H
index 19d8fb63de..b3cbe5567c 100644
--- a/src/OpenFOAM/primitives/bools/bool/bool.H
+++ b/src/OpenFOAM/primitives/bools/bool/bool.H
@@ -45,10 +45,10 @@ class Ostream;
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-Istream& operator>>(Istream&, bool&);
-Ostream& operator<<(Ostream&, const bool);
+Istream& operator>>(Istream& is, bool& b);
+Ostream& operator<<(Ostream& os, const bool b);
 
-bool readBool(Istream&);
+bool readBool(Istream& is);
 
 } // End namespace Foam
 
@@ -61,7 +61,7 @@ bool readBool(Istream&);
 namespace Foam
 {
 
-// template specialisation for pTraits<bool>
+// Template specialisation for pTraits<bool>
 template<>
 class pTraits<bool>
 {
@@ -95,10 +95,10 @@ public:
     // Constructors
 
         //- Construct from primitive
-        explicit pTraits(const bool&);
+        explicit pTraits(const bool& p);
 
         //- Construct from Istream
-        pTraits(Istream&);
+        pTraits(Istream& is);
 
 
     // Member Functions
diff --git a/src/OpenFOAM/primitives/bools/bool/boolIO.C b/src/OpenFOAM/primitives/bools/bool/boolIO.C
index 60518849cf..f098a3e186 100644
--- a/src/OpenFOAM/primitives/bools/bool/boolIO.C
+++ b/src/OpenFOAM/primitives/bools/bool/boolIO.C
@@ -21,17 +21,11 @@ License
     You should have received a copy of the GNU General Public License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
-Description
-    Reads an bool from an input stream, for a given version number and file
-    format. If an ASCII file is being read, then the line numbers are counted
-    and an erroneous read is reported.
-
 \*---------------------------------------------------------------------------*/
 
-#include "error.H"
-
 #include "bool.H"
 #include "Switch.H"
+#include "error.H"
 #include "IOstreams.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -51,8 +45,8 @@ Foam::Ostream& Foam::operator<<(Ostream& os, const bool b)
 {
     // we could also write as text string without any difficulty
     // os  << (b ? "true" : "false");
-    os.write(label(b));
-    os.check("Ostream& operator<<(Ostream&, const bool)");
+    os.write(int(b));
+    os.check(FUNCTION_NAME);
     return os;
 }
 
diff --git a/src/OpenFOAM/primitives/direction/direction.H b/src/OpenFOAM/primitives/direction/direction.H
index b382c20aee..8f8c8c2727 100644
--- a/src/OpenFOAM/primitives/direction/direction.H
+++ b/src/OpenFOAM/primitives/direction/direction.H
@@ -48,10 +48,10 @@ class Ostream;
 
 typedef uint8_t direction;
 
-direction readDirection(Istream&);
-Istream& operator>>(Istream&, direction&);
-Ostream& operator<<(Ostream&, const direction);
-std::ostream& operator<<(std::ostream&, const direction);
+direction readDirection(Istream& is);
+Istream& operator>>(Istream& is, direction& d);
+Ostream& operator<<(Ostream& os, const direction d);
+std::ostream& operator<<(std::ostream& os, const direction d);
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
diff --git a/src/OpenFOAM/primitives/direction/directionIO.C b/src/OpenFOAM/primitives/direction/directionIO.C
index f8a8812a01..e733515933 100644
--- a/src/OpenFOAM/primitives/direction/directionIO.C
+++ b/src/OpenFOAM/primitives/direction/directionIO.C
@@ -61,17 +61,15 @@ Foam::Istream& Foam::operator>>(Istream& is, direction& d)
         return is;
     }
 
-    // Check state of Istream
-    is.check("Istream& operator>>(Istream&, direction&)");
-
+    is.check(FUNCTION_NAME);
     return is;
 }
 
 
 Foam::Ostream& Foam::operator<<(Ostream& os, const direction d)
 {
-    os.write(label(d));
-    os.check("Ostream& operator<<(Ostream&, const direction)");
+    os.write(int(d));
+    os.check(FUNCTION_NAME);
     return os;
 }
 
diff --git a/src/OpenFOAM/primitives/predicates/predicates.H b/src/OpenFOAM/primitives/predicates/predicates.H
new file mode 100644
index 0000000000..8731fb4518
--- /dev/null
+++ b/src/OpenFOAM/primitives/predicates/predicates.H
@@ -0,0 +1,142 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     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/>.
+
+Namespace
+    Foam::predicates
+
+Description
+    Various constant predicate types.
+
+SourceFiles
+    predicates.H
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef predicates_H
+#define predicates_H
+
+#include <string>
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+namespace predicates
+{
+
+/*---------------------------------------------------------------------------*\
+                           Class always Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Unary and binary predicates returning true, useful for templating.
+class always
+{
+public:
+    typedef always value_type;
+
+    //- Construct null
+    inline always()
+    {}
+
+    //- Evalulated as a bool - return true
+    inline operator bool() const
+    {
+        return true;
+    }
+
+    //- Unary predicate returning true
+    template<class T>
+    inline bool operator()(const T&) const
+    {
+        return true;
+    }
+
+    //- Binary predicate returning false
+    template<class T1, class T2>
+    inline bool operator()(const T1&, const T2&) const
+    {
+        return true;
+    }
+
+    //- String matching returning true
+    inline bool match(const std::string& unused, bool literal=false) const
+    {
+        return true;
+    }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                            Class never Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Unary and binary predicates returning false, useful for templating.
+class never
+{
+public:
+    typedef never value_type;
+
+    //- Construct null
+    inline never()
+    {}
+
+    //- Evalulated as a bool - return false
+    inline operator bool() const
+    {
+        return false;
+    }
+
+    //- Unary predicate returning false
+    template<class T>
+    inline bool operator()(const T&) const
+    {
+        return false;
+    }
+
+    //- Binary predicate returning false
+    template<class T1, class T2>
+    inline bool operator()(const T1&, const T2&) const
+    {
+        return false;
+    }
+
+    //- String matching returning false
+    inline bool match(const std::string& unused, bool literal=false) const
+    {
+        return false;
+    }
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace predicates
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //