criterion = DocumentCriterion.class.cast(c);
break;
case MqlParser.FIELD_FUNCTION_CRITERION:
fieldName = child(tree, 0).getText().trim();
criterion = new FieldCriterion(fieldName, createCriterion(tree, ctx));
break;
case MqlParser.COMPARE_CRITERION:
fieldName = child(tree, 0).getText().trim();
criterion = new FieldCriterion(fieldName, createCriterion(tree, ctx));
break;
case MqlParser.NEGATED_CRITERION:
fieldName = child(tree, 0).getChild(0).getText().trim();
criterion = new NotCriterion(fieldName, createCriterion(child(tree, 0), ctx));