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Postings from May 2003
Joseph Paish wrote: > i want to return multiple values from a subroutine. all the examples i have > seen show just a single value (sometimes an array) being returned, and until > now i have been creating an array just for this purpose. I think the reason behind this has to do with the roots of algorithm development in theoretical math. Subroutines have long been associated with functions, which are used in mathematics as conceptual funnels, taking one or more inputs, performing a single operation, and returning the output of that operation. This has some benefits, one of them being that a function in C could be interpolated directly as a variable. In the development of Perl, Larry Wall rebelled against the injunction that functions must always be used in that way. See the intro to Learning Perl for his story on this. Thus Perl does provide facilities for returning an entire data set from a subprocedure, where that is the natural product of the activity. A caveat here. Taking advantage of this Perl feature too much can lead to importable programming habits, since few other languages support multiple-value return. For this reason, I would recommend that you also explore the use of reference parameters for processes intended to modify multiple values. Passing in a reference allows your function to reach out to the calling scope. This is the strategy that tends to have more cross-language applicability, IMHO. JosephThread Previous | Thread Next