Here's a demonstration of how ColdFusion doesn't actually pass things by reference. (derived from http://cfmlblog.adamcameron.me/2012/08/complex-data-types-in-cf-and-how-theyre.html)

structPassByValueOfReference.cfm

<cfscript>

st1 = {
    one     = "Tahi",
    two     = "Rua",
    three   = "Toru",
    four    = "Wha"
};
st2 = f(st1);

function f(st){
    st = {
        one     = "Ichi",
        two     = "Ni",
        three   = "San",
        four    = "Shi"
    };
   
    return st;
}; 
writeOutput('<p>If struct was passed to the function by reference this would have changed both st1 and st2,  but since it was by value-of-the-reference, when we re-built the st struct it overwrote the reference.</p>');
writeDump(var = st1, label = 'st1');
writeDump(var = st2, label = 'st2');

st3 = f2(st1);
function f2(st){
    st.one = "changed";
    return st;
};

writeOutput('<p>Here we see that just changing a key in st changed for both st1 and st3 ( since we didn''t overwrite the reference); </p>');
writeDump(var = st1, label = 'st1');
writeDump(var = st2, label = 'st2');
writeDump(var = st3, label = 'st3');
</cfscript>