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Context aware functions - best practices?by Aristotle (Chancellor)
|on Jan 14, 2003 at 18:22 UTC||Need Help??|
Aristotle has asked for the
wisdom of the Perl Monks concerning the following question:
One thing that has bugged me in a while is the fact that context propagates in Perl in ways that can sometimes lead to surprising results if you haven't realised what's going on. I haven't actually tripped over this particular problem as I was aware of it to begin with, but I'm not sure what the best way to solve it would be:
I'm building a list to return in a function, and naturally I'm storing it in an array. This function is meant to be called with any number of parameters, map each of them to a result, and return the pile. In this particular case, I'm passing CGI parameter names and an untaint spec for each. Obviously I'm often assigning the results to a fresh batch of lexical variables and of course sometimes I want to call it with just a single parameter. There's the quandary:
The result is 1 of course because that's the number of elements in @arr - the value an array evaluates to in scalar context, which I established by omitting the parens on the my. The only clean and robust solution I can think of is somewhat awkward: return wantarray ? @arr : $arr;
Am I missing any simpler idiom?
Makeshifts last the longest.