Re: Re: Condensing code...golfing with push and return

One note:

The original code had return undef, your code has just return. They are not the same.

A bare return is basically equivalen to:

return wantarray ? () : undef;
[download]

your solution is equivalent to:

return wantarray ? (undef) : undef;
[download]

i.e. returns an array with a single element with an undefined value. As opposed to an empty array.

Liz

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Re^3: Condensing code...golfing with push and return by Aristotle (Chancellor) on Oct 10, 2003 at 17:58 UTC
Good observation, and it's good you bring it up. The point is that a list with one element evaluates as true. Most people who say `return undef` or `return 0` actually just want to return a false value, not an explicit `undef` or `0`. It's good habit to use an unadorned return to signal falsehood; something as innocent as `if( my ($obj) = test() ) { # ... }` [download] can trip you up. Makeshifts last the longest.	[reply] [d/l]
Re^4: Condensing code...golfing with push and return (mixed blessing) by tye (Sage) on Oct 10, 2003 at 21:16 UTC
No, use the proper return type for the proper function type. If you return an empty list for false, then you'll be tripped up by something as simple as: `my %hash= ( this => GetThis(), foo => 'bar', baz => 'biff', ); # Which results in: # $hash{this} eq "foo" # ! exists $hash{foo} # $hash{bar} eq 'baz' # ! exists $hash{baz} # exists $hash{biff}` [download] If your function returns lists, then an empty list is likely the correct thing to return for "false". If your function never returns lists, then I'd have it return a false scalar value not an empty list. BTW, my favorite false value is `!1` which is a lot like `''` except that it won't give a warning if used in a numeric context. (It is what Perl's own functions return for "false but not undefined".) - tye	[reply] [d/l] [select]
Re^5: Condensing code...golfing with push and return (mixed blessing) by Aristotle (Chancellor) on Oct 10, 2003 at 22:25 UTC
I know; personally, I tend to do something like `use constant TRUE => 1; use constant FALSE => !TRUE;` [download] when I'm going to need those a lot (it's sometimes helpful to be able to communicate that you mean "true value" and not "numerical one"). As for context, you are right; I guess it's a matter of habit. I'd tend to write that hash construction like `my %hash= ( this => scalar GetThis(), foo => 'bar', baz => 'quux', );` [download] That's probably CGI.pm's legacy.. :) Makeshifts last the longest.	[reply] [d/l] [select]