/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2112                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dictionary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

expr1   "hypot(3,4)";

expr2   hypot(3,4);

expr3   #{  hypot(3,4)  #};

eval1   #eval " pi() * 2 * $expr1";

eval2   #eval " pi() * 2 * $expr2";

eval3   #eval " pi() * 2 * $expr3";


factor  "pi()";

factor10  10;

hypot_a 3;
hypot_b 4;

eval4   #eval "$factor * 2 * hypot(${hypot_xx:-0}, $hypot_b)";

//eval5   #eval " pi() * 2 * ${{ hypot(3,4) * 100 }}";

eval6   #eval " pi() * 2 * ${{ ${factor:-0} * ${{ 15 * 3 }} }} + 5";

eval6a  #eval " pi() * 2 * ${{ ${factor:+-$factor} * ${{ 15 * 3 }} }} + 5";

eval6b  #eval " pi() * 2 * ${{ ${unknown:-0} * ${{ 15 * 3 }} }} + 5";

eval6c  #eval " pi() * 2 * ${{ -${unknown:-0} * ${{ 15 * 3 }} }} + 5";

// Even this work
eval7a  #eval " pi() * 1 * ${factor${{2*5}}:-100}";

// Even this work
eval7b  #eval " pi() * 1 * ${factorXYZ${{2*5}}:-100}";

index   10;

eval8a  #eval " pi() * 2 * ${{ ${factor$index} + ${factor10} }}";

eval8b  #eval " pi() * 2 * $factor * ${{ 100 }}";

eval10a #eval "vector(1,2,3) * 5";


// Slightly stranger ideas:

axis1   (1 0 0);
axis2   (0 1 0);
axis3   (0 0 1);
index   100;

location #eval #{
    400 *

    // Numerator: use the index to get relevant suffix [1,2,3]
    // to form the lookup of axis1,axis2,...
    // Treat the lookup as a vector within the expression evaluation

    $[(vector)   axis${{
            ($index % 3) + 1 /* Evaluates: 1,2,3 from index */ }}
     ]

    // Denominator: divide by index with zero-division protection
  / ${{max(1, $index)}}

    // Same thing, but using expressions-syntax for variable lookup
  / ${{max(1, $[index])}}
#};


// This is still a rather clunky syntax
length #eval{ cbrt(mag($[(vector) location])) };


// Remove evidence of some variables
#remove ("axis[0-9]*" index)

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