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Postings from November 2008
Michael G Schwern wrote: > demerphq wrote: >> 2008/10/31 Michael G Schwern <schwern@pobox.com>: >>> This came up on #perl recently, why are the filetest operators in perlfunc? >>> They sure look like unary operators to me. I wouldn't think to look for them >>> amongst the functions. >>> >>> There's only one mention of them in perlop, and that's this. >>> >>> Regarding precedence, the filetest operators, like "-f", "-M", etc. are >>> treated like named unary operators, but they don't follow this func- >>> tional parenthesis rule. That means, for example, that >>> "-f($file).".bak"" is equivalent to "-f "$file.bak"". >>> >>> Even the perlfunc entry says they're ops. >>> >>> -X FILEHANDLE >>> -X EXPR >>> -X A file test, where X is one of the letters listed below. This >>> unary operator takes one argument >>> >>> Would anyone be opposed to their docs being moved to perlop? >> >> Change perlfunc to not call them ops. They aren't operators, they are >> functions, *with* side effects. Calling them operators at all is >> wrong. > > Why are they functions? What makes a function and what makes an operator? > What's the difference between a file test operator/function and a unary operator? Perl 6's take on this is that an operator is a funnily named function that also happens to have a precedence level and an associativity. Since -X is certainly "funnily named" it's an operator ;-) Moritz