[sf-perl] Sort subroutine didn't return single value at -e line 1.

[Uri Guttman]

On 04/05/2013 06:13 PM, Bill Moseley wrote:
> On Fri, Apr 5, 2013 at 2:46 PM, Uri Guttman <uri at stemsystems.com> wrote:
>
>>
>> sort takes a sub name for its first arg if that is a bareword. so you are
>> sorting the whole list but using uniq as the comparison function.
>>
>> try putting parens around the list so uniq looks like a sub. or parens
>> around uniq and the list but that is wrong because sort defaults to alpha
>> sorting and that will only work on numbers of the same length.
>
>
> Oh, I had tried parens, but I guess it's still seen as a barword.
>
> $ perl -wle 'use Data::Dumper; use List::MoreUtils "uniq";  print Dumper
> [sort uniq( 3,1,3,2)]'
> $VAR1 = [
>            1,
>            2,
>            3,
>            3
>          ];
>
> as well as "sort (uniq 3,1,3,2)"

seems to be parsed that way.
>
>
>
> Does the plus sign tell sort it's not a bareword in this case?
>
> $ perl -wle 'use Data::Dumper; use List::MoreUtils "uniq";  print Dumper
> [sort +uniq 3,1,3,2]'
> $VAR1 = [
>            1,
>            2,
>            3
>          ];
>
yes. you can always make any bareword into a function call with a 
preceding plus. it is a noop from a semantic view but it lets the parser 
know it is an expression and not a bareword.

> Yes, still need to deal with the numeric sort, but I was just using that
> list as an example.

if you had the numeric comparison block as you know about, this problem 
would never have surfaced. using good example data is important too.

uri