for (int i = 0; i < node.jjtGetNumChildren(); i++) {
Node child = node.jjtGetChild(i);
if(child instanceof ASTFieldId) {
CodeType id = owsf.createCodeType();
id.setValue((String) child.jjtAccept(this, null));
fs.setIdentifier(id);
} else if(child instanceof ASTInterpolation) {
fs.setInterpolationType((String) child.jjtAccept(this, null));
} else if(child instanceof ASTAxisSubset) {
fs.getAxisSubset().add(child.jjtAccept(this, null));