data/test/dictionary/testDict

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  dev
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    object      testDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// To expand this dictionary run
//     foamDictionary -expand testDict

internalField 3.4;

active
{
    type            fixedValue;
    value.air       $internalField;
}

inactive
{
    type            anotherFixedValue;

    value           $../active/value.air;
    anotherValue    $!active/value.air;

    sub
    {
        value           $../../active/value.air;
        anotherValue    $!active/value.air;
    }
}

"U.*"
{
    solver GAMG;
}

e.air
{
    // This does expand
    $U.air;
}

external
{
    value $testDict2!active/value.air;
}

activeWater
{
    $testDict2!active;
    value.water     1000;
}

activeAir
{
    ${${FOAM_CASE}/testDict2!active};
}

whichActive activeWater;

#ifeq ($whichActive activeWater)
    active2
    {
        $activeWater;
    }
#else
    active2
    {
        $activeAir;
    }
#endif

// ************************************************************************* //