String treeName = tree.getText().toUpperCase();
// Select appropriate function (and create it)
if( treeName.equals("+") ) {
FclObject terms[] = parseTerms(functionBlock, tree);
return new MffSum(functionBlock, terms);
} else if( treeName.equals("-") ) {
FclObject terms[] = parseTerms(functionBlock, tree);
return new MffSubstract(functionBlock, terms);
} else if( treeName.equals("*") ) {
FclObject terms[] = parseTerms(functionBlock, tree);