Hi, a tricky situation: <hansl> function void hey(matrix mm) string huhu = argname(mm) slen = strlen(huhu) print slen end function bundle bc = null matrix bc.m = zeros(3,2) hey(bc.m) </hansl> The length of the argname(mm) result string is zero. According to the argname doc, this happens if the argument was passed "anonymously". I understand that it's not really clear what the argname of bc.m should be, being a member of a bundle. However, this limitation is kind of unsatisfactory IMO, because I'm passing the correct parameter type to the function, but then it breaks down because the parameter happens to come from inside a bundle, which should be irrelevant from the point of view of the function. Hm, as I said, tricky to resolve. thanks, sven