get current instruction calling tree
[linenum,mac]=where()
:linenum a column vector of integers : :mac a column vector of strings :
[linenum,mac]=where() returns linenum and mac such as current instruction has been called by the linenum(1) line of function mac(1), mac(1) has been called by the linenum(2) line of function mac(2) and so on.
mac(i) is in general the name of a function but it may also be “exec” or “execstr” if instruction lies in an exec file or an execstr instruction.