problem with document keys starting with numbers

[mete]

Hello,

Sorry for asking this fundamental thing but i am having some issues with
document keys that start with numbers, For instance when i create a view
like this:

function(doc) {
emit(doc.x, {'id':doc.id,'x':doc.x})
}

If x is "x" or "x123" etc its fine but

if x is "2v2" or "5abcd" etc.. i get the "Expression does not eval to a
function." error. Any ideas?

thanks in advance

Mete