Re^3: most appropriate return data type

The caller forces context on the return. The return value is the result of the evaluation (in the context of the caller) of the last expression in a subroutine (or the expression given to return).

So..

an array in scalar context is the number of items in it.
in scalar context the expression ('a','b','c') isn't a list, it's a chain of comma operations:
In scalar context, the comma operator throws away it's left operand and evaluates the right operand. So the result is c
the qw// operator is the comma operator in disguise

See perlop. Ah, and 'fox' gets assigned to '$y' </nitpick> ;-)

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Re^4: most appropriate return data type by merlyn (Sage) on Feb 19, 2010 at 16:43 UTC
the qw// operator is the comma operator in disguise It is now. It used to be the `split` function, in which case, you'd get a split-in-a-scalar-context which would clobber `@_` and trigger a warning and return 4. :) -- Randal L. Schwartz, Perl hacker The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.	[reply] [d/l] [select]
Re^5: most appropriate return data type by TGI (Parson) on Feb 24, 2010 at 20:38 UTC
I didn't know that about the changes to `qw//`. I've had some rude surprises when I've written subs that were intended to return lists. That's why I always use an intermediate variable or an explicit `wantarray` call in when I write a sub that will normally return a list. Things like `return 7..5` can have surprising effects in scalar context. Most of the time, a sub that returns a list should act like an array in scalar context, assigning to an intermediate array is a simple way to get context aware results. When other behavior is desired, I prefer to explicitly construct the result set using wantarray. `sub seven_in_scalar_context { my @r = 3..9; return @r; } sub nine_in_scalar_context { my @r = 3..9; return wantarray ? @r : $r[-1]; }` [download] Array behavior in scalar context is pretty well known, so I feel good about using it implicitly. I've seen too many questions about other kinds of contextual returns (especially the regarding the comma) to feel good about using them implicitly. So I use `wantarray` everywhere else. TGI says moo	[reply] [d/l] [select]