diff --git a/src/OpenFOAM/primitives/strings/keyType/keyTypeI.H b/src/OpenFOAM/primitives/strings/keyType/keyTypeI.H
new file mode 100644
index 000000000..62fd662f3
--- /dev/null
+++ b/src/OpenFOAM/primitives/strings/keyType/keyTypeI.H
@@ -0,0 +1,127 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright held by original author
+     \\/     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 2 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, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+\*---------------------------------------------------------------------------*/
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+inline Foam::keyType::keyType()
+:
+    word(),
+    isPattern_(false)
+{}
+
+
+inline Foam::keyType::keyType(const keyType& s)
+:
+    word(s, false),
+    isPattern_(s.isPattern())
+{}
+
+
+inline Foam::keyType::keyType(const word& s)
+:
+    word(s, false),
+    isPattern_(false)
+{}
+
+
+// Construct as copy of string. Expect it to be regular expression
+inline Foam::keyType::keyType(const string& s)
+:
+    word(s, false),
+    isPattern_(true)
+{}
+
+
+// Construct as copy of character array
+inline Foam::keyType::keyType(const char* s)
+:
+    word(s, false),
+    isPattern_(false)
+{}
+
+
+//- Construct as copy of std::string
+inline Foam::keyType::keyType
+(
+    const std::string& s,
+    const bool isPattern
+)
+:
+    word(s, false),
+    isPattern_(isPattern)
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+inline bool Foam::keyType::isPattern() const
+{
+    return isPattern_;
+}
+
+
+// * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
+
+inline const Foam::keyType& Foam::keyType::operator=(const keyType& s)
+{
+    // Bypass checking
+    string::operator=(s);
+    isPattern_ = s.isPattern_;
+    return *this;
+}
+
+
+inline const Foam::keyType& Foam::keyType::operator=(const word& s)
+{
+    word::operator=(s);
+    isPattern_ = false;
+    return *this;
+}
+
+
+inline const Foam::keyType& Foam::keyType::operator=(const string& s)
+{
+    // Bypass checking
+    string::operator=(s);
+    isPattern_ = true;
+    return *this;
+}
+
+
+inline const Foam::keyType& Foam::keyType::operator=(const char* s)
+{
+    // Bypass checking
+    string::operator=(s);
+    isPattern_ = false;
+    return *this;
+}
+
+
+// ************************************************************************* //