The @ as a dereferencing operator (as you are using it) expects a reference, and thus puts its argument in scalar context. The return value of localtime in scalar context is a scalar (a string, to be precise). You want localtime to be called in list context.

What you're looking for is (localtime)[1,3]. This causes localtime to be called in list context, and then takes elements 1 and 3 from the resultant list. However, be extra careful with that syntax when using it with print -- perl -e'print (localtime)[1,3]' won't work because it's interpreted as calling print with the argument localtime. Try either enclosing the whole slice in an extra set of parens, or putting a `+' in front of the first paren.

The reason your last example works is that you're return a single value from your subroutine, namely a reference to an array. @{...} dereferences that array, and then the slice grabs the elements you want from it. You could fix your first subroutine example similarly to the localtime fix.

Finally, and I know this is just an example, be very careful about naming subroutines `m'. It can cause some painful ambiguity with the m operator.

-dlc