From c378893bcb64c803be5d5b5859cf910ecb5f92ac Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@keysight.com>
Date: Tue, 2 Sep 2025 14:54:06 +0200
Subject: [PATCH] ENH: simplify direct creation of dictionary primitive entries

- can now create an empty entry and add/overwrite with tokens afterwards,
  or copy/move construct from a list of tokens.

ENH: provided named token setter methods (disambiguates bool/char/label)

COMP: use 'if constexpr' for FlatOutput

DOC: more description for Field
---
 .../test/HashPtrTable/Test-HashPtrTable.cxx   |  54 +++++---
 applications/test/ISLList/Make/files          |   2 +-
 .../{Test-ISLList.C => Test-ISLList.cxx}      |   0
 applications/test/PtrDictionary1/Make/files   |   2 +-
 ...rDictionary1.C => Test-PtrDictionary1.cxx} |   8 +-
 applications/test/PtrList/Test-PtrList.cxx    | 126 +++++++++++++++---
 .../test/PtrListDictionary/Make/files         |   2 +-
 ...ictionary.C => Test-PtrListDictionary.cxx} |  12 +-
 applications/test/dictionary/Make/files       |   2 +-
 ...{Test-dictionary.C => Test-dictionary.cxx} |   0
 applications/test/dictionary2/Make/files      |   2 +-
 ...est-dictionary2.C => Test-dictionary2.cxx} |  45 +++++--
 applications/test/dictionaryCopy/Make/files   |   2 +-
 ...ctionaryCopy.C => Test-dictionaryCopy.cxx} |   0
 src/OpenFOAM/db/IOstreams/output/FlatOutput.H |  32 ++---
 src/OpenFOAM/db/IOstreams/token/token.H       |   9 ++
 src/OpenFOAM/db/IOstreams/token/tokenI.H      |  32 ++++-
 src/OpenFOAM/db/dictionary/dictionary.C       |  20 ++-
 src/OpenFOAM/db/dictionary/dictionary.H       |  15 +++
 src/OpenFOAM/fields/Fields/Field/Field.H      |   8 +-
 20 files changed, 284 insertions(+), 89 deletions(-)
 rename applications/test/ISLList/{Test-ISLList.C => Test-ISLList.cxx} (100%)
 rename applications/test/PtrDictionary1/{Test-PtrDictionary1.C => Test-PtrDictionary1.cxx} (97%)
 rename applications/test/PtrListDictionary/{Test-PtrListDictionary.C => Test-PtrListDictionary.cxx} (92%)
 rename applications/test/dictionary/{Test-dictionary.C => Test-dictionary.cxx} (100%)
 rename applications/test/dictionary2/{Test-dictionary2.C => Test-dictionary2.cxx} (90%)
 rename applications/test/dictionaryCopy/{Test-dictionaryCopy.C => Test-dictionaryCopy.cxx} (100%)

diff --git a/applications/test/HashPtrTable/Test-HashPtrTable.cxx b/applications/test/HashPtrTable/Test-HashPtrTable.cxx
index cd4b81184f..c2bb47012e 100644
--- a/applications/test/HashPtrTable/Test-HashPtrTable.cxx
+++ b/applications/test/HashPtrTable/Test-HashPtrTable.cxx
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011 OpenFOAM Foundation
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -42,33 +42,55 @@ Description
 
 using namespace Foam;
 
-class Scalar
+bool verbosity = true;
+
+// Gratuitous class inheritance
+template<class T>
+class BoxedType
 {
-    scalar data_;
+    T data_;
 
 public:
 
     static bool verbose;
 
-    constexpr Scalar() noexcept : data_(0) {}
-    Scalar(scalar val) noexcept : data_(val) {}
+    constexpr BoxedType() noexcept : data_(0) {}
+    BoxedType(T val) noexcept : data_(val) {}
+
+    ~BoxedType()
+    {
+        if (verbosity) Info<< "    [delete BoxedType: " << value() << ']' << nl;
+    }
+
+    T value() const noexcept { return data_; }
+    T& value() noexcept { return data_; }
+
+    auto clone() const { return autoPtr<BoxedType<T>>::New(*this); }
+};
+
+template<class T> Ostream& operator<<(Ostream& os, const BoxedType<T>& item)
+{
+    return (os << " -> " << item.value());
+}
+
+
+class Scalar : public BoxedType<scalar>
+{
+public:
+
+    using BoxedType<scalar>::BoxedType;
 
     ~Scalar()
     {
-        if (verbose) Info<< "delete Scalar: " << data_ << endl;
-    }
-
-    const scalar& value() const noexcept { return data_; }
-    scalar& value() noexcept { return data_; }
-
-    friend Ostream& operator<<(Ostream& os, const Scalar& item)
-    {
-        os  << item.value();
-        return os;
+        if (verbosity) Info<< "delete Scalar: " << value() << nl;
     }
+    auto clone() const { return autoPtr<Scalar>::New(*this); }
 };
 
-bool Scalar::verbose = true;
+Ostream& operator<<(Ostream& os, const Scalar& item)
+{
+    return (os << item.value());
+}
 
 
 template<class T>
diff --git a/applications/test/ISLList/Make/files b/applications/test/ISLList/Make/files
index ceb5fc148f..26f3e12d5f 100644
--- a/applications/test/ISLList/Make/files
+++ b/applications/test/ISLList/Make/files
@@ -1,3 +1,3 @@
-Test-ISLList.C
+Test-ISLList.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-ISLList
diff --git a/applications/test/ISLList/Test-ISLList.C b/applications/test/ISLList/Test-ISLList.cxx
similarity index 100%
rename from applications/test/ISLList/Test-ISLList.C
rename to applications/test/ISLList/Test-ISLList.cxx
diff --git a/applications/test/PtrDictionary1/Make/files b/applications/test/PtrDictionary1/Make/files
index 9ced445619..c21cc1053a 100644
--- a/applications/test/PtrDictionary1/Make/files
+++ b/applications/test/PtrDictionary1/Make/files
@@ -1,3 +1,3 @@
-Test-PtrDictionary1.C
+Test-PtrDictionary1.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-PtrDictionary1
diff --git a/applications/test/PtrDictionary1/Test-PtrDictionary1.C b/applications/test/PtrDictionary1/Test-PtrDictionary1.cxx
similarity index 97%
rename from applications/test/PtrDictionary1/Test-PtrDictionary1.C
rename to applications/test/PtrDictionary1/Test-PtrDictionary1.cxx
index 3f407568bc..c9bedb58e9 100644
--- a/applications/test/PtrDictionary1/Test-PtrDictionary1.C
+++ b/applications/test/PtrDictionary1/Test-PtrDictionary1.cxx
@@ -42,6 +42,8 @@ Description
 
 using namespace Foam;
 
+bool verbosity = true;
+
 class ent
 :
     public Dictionary<ent>::link
@@ -73,14 +75,12 @@ class Scalar
 
 public:
 
-    static bool verbose;
-
     constexpr Scalar() noexcept : data_(0) {}
     Scalar(scalar val) noexcept : data_(val) {}
 
     ~Scalar()
     {
-        if (verbose) Info<< "delete Scalar: " << data_ << endl;
+        if (verbosity) Info<< "delete Scalar: " << data_ << endl;
     }
 
     scalar value() const noexcept { return data_; }
@@ -93,8 +93,6 @@ public:
     }
 };
 
-bool Scalar::verbose = true;
-
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 //  Main program:
diff --git a/applications/test/PtrList/Test-PtrList.cxx b/applications/test/PtrList/Test-PtrList.cxx
index 88c8cfbffe..17f72460c7 100644
--- a/applications/test/PtrList/Test-PtrList.cxx
+++ b/applications/test/PtrList/Test-PtrList.cxx
@@ -41,35 +41,85 @@ Description
 
 using namespace Foam;
 
-class Scalar
+bool verbosity = true;
+
+// Gratuitous class inheritance
+template<class T>
+class BoxedType
 {
-    scalar data_;
+    T data_;
 
 public:
 
     static bool verbose;
 
-    constexpr Scalar() noexcept : data_(0) {}
-    Scalar(scalar val) noexcept : data_(val) {}
+    constexpr BoxedType() noexcept : data_(0) {}
+    BoxedType(T val) noexcept : data_(val) {}
+
+    ~BoxedType()
+    {
+        if (verbosity) Info<< "    [delete BoxedType: " << value() << ']' << nl;
+    }
+
+    T value() const noexcept { return data_; }
+    T& value() noexcept { return data_; }
+
+    auto clone() const { return autoPtr<BoxedType<T>>::New(*this); }
+};
+
+template<class T> Ostream& operator<<(Ostream& os, const BoxedType<T>& item)
+{
+    return (os << " -> " << item.value());
+}
+
+
+class Scalar : public BoxedType<scalar>
+{
+public:
+
+    using BoxedType<scalar>::BoxedType;
 
     ~Scalar()
     {
-        if (verbose) Info<< "delete Scalar: " << data_ << endl;
-    }
-
-    scalar value() const noexcept { return data_; }
-    scalar& value() noexcept { return data_; }
-
-    autoPtr<Scalar> clone() const { return autoPtr<Scalar>::New(data_); }
-
-    friend Ostream& operator<<(Ostream& os, const Scalar& item)
-    {
-        os  << item.value();
-        return os;
+        if (verbosity) Info<< "delete Scalar: " << value() << nl;
     }
+    auto clone() const { return autoPtr<Scalar>::New(*this); }
 };
 
-bool Scalar::verbose = true;
+Ostream& operator<<(Ostream& os, const Scalar& item)
+{
+    return (os << item.value());
+}
+
+
+class Integer : public BoxedType<label>
+{
+public:
+
+    using BoxedType<label>::BoxedType;
+
+    ~Integer()
+    {
+        if (verbosity) Info<< "delete Integer: " << value() << nl;
+    }
+    auto clone() const { return autoPtr<Integer>::New(*this); }
+};
+
+Ostream& operator<<(Ostream& os, const Integer& item)
+{
+    return (os << item.value());
+}
+
+
+//- Permit up-casting to the base class (eg, fvMesh to polyMesh).
+//  Usually only for holding (const) references.
+//  Exercise caution with the
+template<class Base, class Derived>
+std::enable_if_t<std::is_base_of_v<Base, Derived>, const UPtrList<Base>&>
+upcast(const UPtrList<Derived>& This)
+{
+    return *reinterpret_cast<const UPtrList<Base>*>(&This);
+}
 
 
 // As per
@@ -251,9 +301,9 @@ int main(int argc, char *argv[])
 
         Info<< "DLPtrList: " << llist1 << endl;
 
-        Scalar::verbose = false;
+        verbosity = false;
         llist1.clear();
-        Scalar::verbose = true;
+        verbosity = true;
     }
     #endif
 
@@ -331,6 +381,44 @@ int main(int argc, char *argv[])
     }
 
 
+    // Test upcasting - dangerous
+    {
+        const auto& base =
+            *reinterpret_cast<UPtrList<BoxedType<scalar>>*>(&list1);
+
+        Info<< "list :" << list1 << nl;
+        Info<< "base :" << base << nl;
+    }
+
+    // Expect bad things to happen!!
+    {
+        const auto& base =
+            *reinterpret_cast<UPtrList<BoxedType<label>>*>(&list1);
+
+        Info<< "list :" << list1 << nl;
+        Info<< "base :" << base << nl;
+    }
+
+    // Test upcasting - compile safer (make as member function?)
+    {
+        // const auto& base = list1.upcast<BoxedType<scalar>>();
+        const auto& base = upcast<BoxedType<scalar>>(list1);
+
+        Info<< "list :" << list1 << nl;
+        Info<< "base :" << base << nl;
+    }
+
+    // Refuse to compile (good!)
+    #if 0
+    {
+        // const auto& base = list1.upcast<BoxedType<label>>();
+        const auto& base = upcast<BoxedType<label>>(list1);
+
+        Info<< "list :" << list1 << nl;
+        Info<< "base :" << base << nl;
+    }
+    #endif
+
     PtrList<Scalar> list2(15);
     Info<< "Emplace set " << list2.size() << " values" << nl;
     forAll(list2, i)
diff --git a/applications/test/PtrListDictionary/Make/files b/applications/test/PtrListDictionary/Make/files
index a3c4c87ba4..bc96e4308d 100644
--- a/applications/test/PtrListDictionary/Make/files
+++ b/applications/test/PtrListDictionary/Make/files
@@ -1,3 +1,3 @@
-Test-PtrListDictionary.C
+Test-PtrListDictionary.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-PtrListDictionary
diff --git a/applications/test/PtrListDictionary/Test-PtrListDictionary.C b/applications/test/PtrListDictionary/Test-PtrListDictionary.cxx
similarity index 92%
rename from applications/test/PtrListDictionary/Test-PtrListDictionary.C
rename to applications/test/PtrListDictionary/Test-PtrListDictionary.cxx
index 28a0020827..e77c8d4e09 100644
--- a/applications/test/PtrListDictionary/Test-PtrListDictionary.C
+++ b/applications/test/PtrListDictionary/Test-PtrListDictionary.cxx
@@ -39,26 +39,26 @@ Description
 
 using namespace Foam;
 
+bool verbosity = true;
+
 class Scalar
 {
     scalar data_;
 
 public:
 
-    static bool verbose;
-
     constexpr Scalar() noexcept : data_(0) {}
     Scalar(scalar val) noexcept : data_(val) {}
 
     ~Scalar()
     {
-        if (verbose) Info<< "delete Scalar: " << data_ << endl;
+        if (verbosity) Info<< "delete Scalar: " << value() << nl;
     }
 
-    const scalar& value() const noexcept { return data_; }
+    scalar value() const noexcept { return data_; }
     scalar& value() noexcept { return data_; }
 
-    autoPtr<Scalar> clone() const { return autoPtr<Scalar>::New(data_); }
+    auto clone() const { return autoPtr<Scalar>::New(*this); }
 
     friend Ostream& operator<<(Ostream& os, const Scalar& item)
     {
@@ -67,8 +67,6 @@ public:
     }
 };
 
-bool Scalar::verbose = true;
-
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 //  Main program:
diff --git a/applications/test/dictionary/Make/files b/applications/test/dictionary/Make/files
index ae255d4474..f72adf071d 100644
--- a/applications/test/dictionary/Make/files
+++ b/applications/test/dictionary/Make/files
@@ -1,3 +1,3 @@
-Test-dictionary.C
+Test-dictionary.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-dictionary
diff --git a/applications/test/dictionary/Test-dictionary.C b/applications/test/dictionary/Test-dictionary.cxx
similarity index 100%
rename from applications/test/dictionary/Test-dictionary.C
rename to applications/test/dictionary/Test-dictionary.cxx
diff --git a/applications/test/dictionary2/Make/files b/applications/test/dictionary2/Make/files
index 397d8d53cb..2f33bce74c 100644
--- a/applications/test/dictionary2/Make/files
+++ b/applications/test/dictionary2/Make/files
@@ -1,3 +1,3 @@
-Test-dictionary2.C
+Test-dictionary2.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-dictionary2
diff --git a/applications/test/dictionary2/Test-dictionary2.C b/applications/test/dictionary2/Test-dictionary2.cxx
similarity index 90%
rename from applications/test/dictionary2/Test-dictionary2.C
rename to applications/test/dictionary2/Test-dictionary2.cxx
index da12142e4b..24001b4948 100644
--- a/applications/test/dictionary2/Test-dictionary2.C
+++ b/applications/test/dictionary2/Test-dictionary2.cxx
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -47,8 +47,18 @@ void entryInfo(entry* e)
 {
     if (e)
     {
-        Info<<"added "
-            << e->keyword() << ": " << typeid(e).name() << nl;
+        Info<< "added "
+            << e->keyword() << ": " << typeid(e).name();
+
+        if (auto* stream = e->streamPtr())
+        {
+            Info<< " tokens: "; stream->tokens().writeList(Info);
+        }
+        if (auto* dict = e->dictPtr())
+        {
+            Info<< " dictionary:";
+        }
+        Info<< nl;
     }
 }
 
@@ -200,12 +210,31 @@ int main(int argc, char *argv[])
     {
         dictionary tmpdict;
 
+        // Add an empty entry and populate afterwards
+        if (entry* e = dict1.set(word::printf("entry%d", i), nullptr))
         {
-            entry* e = dict1.add
-            (
-                word::printf("entry%d", i),
-                string("entry" + Foam::name(i))
-            );
+            auto& toks = e->stream();
+            toks.resize(2);
+
+            toks[0] = word("value" + Foam::name(i));
+            toks[1] = 10*i;
+            entryInfo(e);
+        }
+
+        // Add an entry from given list of tokens
+        {
+            tokenList toks(2);
+            toks[0] = word("value" + Foam::name(i));
+            toks[1] = 10*i;
+
+            Info<< "set token0: " << Foam::name(&(toks[0])) << nl;
+
+            entry* e = dict1.set(word::printf("_entry%d", i), std::move(toks));
+
+            // verify that the address is identical (ie, move semantics worked)
+            auto& newToks = e->stream();
+            Info<< "get token0: " << Foam::name(&(newToks[0])) << nl;
+
             entryInfo(e);
         }
 
diff --git a/applications/test/dictionaryCopy/Make/files b/applications/test/dictionaryCopy/Make/files
index 11d085174a..4ce726facf 100644
--- a/applications/test/dictionaryCopy/Make/files
+++ b/applications/test/dictionaryCopy/Make/files
@@ -1,3 +1,3 @@
-Test-dictionaryCopy.C
+Test-dictionaryCopy.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-dictionaryCopy
diff --git a/applications/test/dictionaryCopy/Test-dictionaryCopy.C b/applications/test/dictionaryCopy/Test-dictionaryCopy.cxx
similarity index 100%
rename from applications/test/dictionaryCopy/Test-dictionaryCopy.C
rename to applications/test/dictionaryCopy/Test-dictionaryCopy.cxx
diff --git a/src/OpenFOAM/db/IOstreams/output/FlatOutput.H b/src/OpenFOAM/db/IOstreams/output/FlatOutput.H
index 4737d942fe..ad01214e85 100644
--- a/src/OpenFOAM/db/IOstreams/output/FlatOutput.H
+++ b/src/OpenFOAM/db/IOstreams/output/FlatOutput.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2020 OpenCFD Ltd.
+    Copyright (C) 2017-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -32,8 +32,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef FlatOutput_H
-#define FlatOutput_H
+#ifndef Foam_FlatOutput_H
+#define Foam_FlatOutput_H
 
 #include "Ostream.H"
 
@@ -134,8 +134,8 @@ public:
 
     // Constructors
 
-        //- Construct from component
-        explicit OutputAdaptor(const Container& obj)
+        //- Construct from const reference
+        explicit OutputAdaptor(const Container& obj) noexcept
         :
             values(obj)
         {}
@@ -151,30 +151,22 @@ public:
         //        No special handling for newline separators.
         inline Ostream& write(Ostream& os) const
         {
-            bool started = false;
+            [[maybe_unused]] bool started = false;
 
-            // In c++17, can use constexpr if
-
-            if (Delimiters::open)
+            if constexpr (Delimiters::open)  // Not nul char
             {
-                os  << Delimiters::open;
+                os << Delimiters::open;
             }
             for (const auto& item : values)
             {
-                if (started)
-                {
-                    if (Delimiters::separator)
-                    {
-                        os  << Delimiters::separator;
-                    }
-                }
-                else
+                if constexpr (Delimiters::separator)  // Not nul char
                 {
+                    if (started) os << Delimiters::separator;
                     started = true;
                 }
-                os  << item;
+                os << item;
             }
-            if (Delimiters::close)
+            if constexpr (Delimiters::close)  // Not nul char
             {
                 os << Delimiters::close;
             }
diff --git a/src/OpenFOAM/db/IOstreams/token/token.H b/src/OpenFOAM/db/IOstreams/token/token.H
index 45724f6e74..bebff97161 100644
--- a/src/OpenFOAM/db/IOstreams/token/token.H
+++ b/src/OpenFOAM/db/IOstreams/token/token.H
@@ -717,6 +717,9 @@ public:
         //  Report FatalIOError and return false if token is not BOOL or LABEL
         inline bool boolToken() const;
 
+        //- Assign to a boolean token
+        inline void boolToken(bool on);
+
         //- Return flag bitmask value.
         //  Report FatalIOError and return NO_FLAG if token is not FLAG
         inline int flagToken() const;
@@ -725,10 +728,16 @@ public:
         //  Report FatalIOError and return \b \\0 if token is not PUNCTUATION
         inline punctuationToken pToken() const;
 
+        //- Assign to a punctuation token
+        inline void pToken(const punctuationToken p);
+
         //- Return label value.
         //  Report FatalIOError and return \b 0 if token is not LABEL
         inline label labelToken() const;
 
+        //- Assign to a label token
+        inline void labelToken(const label val);
+
         //- Return float value.
         //  Report FatalIOError and return \b 0 if token is not FLOAT
         inline float floatToken() const;
diff --git a/src/OpenFOAM/db/IOstreams/token/tokenI.H b/src/OpenFOAM/db/IOstreams/token/tokenI.H
index a8fd3cac7b..f3996589f8 100644
--- a/src/OpenFOAM/db/IOstreams/token/tokenI.H
+++ b/src/OpenFOAM/db/IOstreams/token/tokenI.H
@@ -547,6 +547,14 @@ inline bool Foam::token::boolToken() const
 }
 
 
+inline void Foam::token::boolToken(bool on)
+{
+    reset();
+    type_ = tokenType::BOOL;
+    data_.labelVal = on;
+}
+
+
 inline bool Foam::token::isFlag() const noexcept
 {
     return (type_ == tokenType::FLAG);
@@ -603,6 +611,14 @@ inline Foam::token::punctuationToken Foam::token::pToken() const
 }
 
 
+inline void Foam::token::pToken(const punctuationToken p)
+{
+    reset();
+    type_ = tokenType::PUNCTUATION;
+    data_.punctuationVal = p;
+}
+
+
 inline bool Foam::token::isLabel() const noexcept
 {
     return
@@ -649,6 +665,14 @@ inline Foam::label Foam::token::labelToken() const
 }
 
 
+inline void Foam::token::labelToken(const label val)
+{
+    reset();
+    type_ = tokenType::LABEL;
+    data_.labelVal = val;
+}
+
+
 inline bool Foam::token::isFloat() const noexcept
 {
     return (type_ == tokenType::FLOAT);
@@ -1031,17 +1055,13 @@ inline void Foam::token::operator=(token&& tok)
 
 inline void Foam::token::operator=(const punctuationToken p)
 {
-    reset();
-    type_ = tokenType::PUNCTUATION;
-    data_.punctuationVal = p;
+    token::pToken(p);
 }
 
 
 inline void Foam::token::operator=(const label val)
 {
-    reset();
-    type_ = tokenType::LABEL;
-    data_.labelVal = val;
+    token::labelToken(val);
 }
 
 
diff --git a/src/OpenFOAM/db/dictionary/dictionary.C b/src/OpenFOAM/db/dictionary/dictionary.C
index 024713199a..42ddcdab3e 100644
--- a/src/OpenFOAM/db/dictionary/dictionary.C
+++ b/src/OpenFOAM/db/dictionary/dictionary.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2023 OpenCFD Ltd.
+    Copyright (C) 2015-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -803,6 +803,24 @@ Foam::entry* Foam::dictionary::set(const keyType& k, const dictionary& v)
 }
 
 
+Foam::entry* Foam::dictionary::set(const keyType& k, std::nullptr_t)
+{
+    return set(new primitiveEntry(k));
+}
+
+
+Foam::entry* Foam::dictionary::set(const keyType& k, const UList<token>& tokens)
+{
+    return set(new primitiveEntry(k, tokens));
+}
+
+
+Foam::entry* Foam::dictionary::set(const keyType& k, List<token>&& tokens)
+{
+    return set(new primitiveEntry(k, std::move(tokens)));
+}
+
+
 bool Foam::dictionary::merge(const dictionary& dict)
 {
     if (this == &dict)
diff --git a/src/OpenFOAM/db/dictionary/dictionary.H b/src/OpenFOAM/db/dictionary/dictionary.H
index 5c185d245a..67f771e3d2 100644
--- a/src/OpenFOAM/db/dictionary/dictionary.H
+++ b/src/OpenFOAM/db/dictionary/dictionary.H
@@ -953,6 +953,21 @@ public:
         //  \return pointer to inserted entry or nullptr on failure
         entry* set(const keyType& k, const dictionary& v);
 
+        //- Assign an empty primitive entry,
+        //- overwriting any existing entry.
+        //  \return pointer to entry or nullptr on failure
+        entry* set(const keyType& k, std::nullptr_t);
+
+        //- Assign a primitive entry from a list of tokens,
+        //- overwriting any existing entry.
+        //  \return pointer to entry or nullptr on failure
+        entry* set(const keyType& k, const UList<token>& tokens);
+
+        //- Assign a primitive entry from a list of tokens,
+        //- overwriting any existing entry.
+        //  \return pointer to entry or nullptr on failure
+        entry* set(const keyType& k, List<token>&& tokens);
+
         //- Assign a T entry, overwriting any existing entry.
         //  \return pointer to inserted entry or nullptr on failure
         template<class T>
diff --git a/src/OpenFOAM/fields/Fields/Field/Field.H b/src/OpenFOAM/fields/Fields/Field/Field.H
index 744ac9fac1..198ee76dd2 100644
--- a/src/OpenFOAM/fields/Fields/Field/Field.H
+++ b/src/OpenFOAM/fields/Fields/Field/Field.H
@@ -28,7 +28,13 @@ Class
     Foam::Field
 
 Description
-    Generic templated field type.
+    Generic templated field type that is much like a Foam::List
+    except that it is expected to hold numerical content
+    (not generic elements such as strings etc).
+
+    In addition to methods specific to numerical fields
+    (e.g., clamp, min, max, transpose, ...), it also has a reference
+    counter that is used by Foam::tmp handling.
 
 SourceFiles
     FieldFunctions.H