Re^2: new keyword "size" to avoid scalar trap ? ( scalar @array != scalar(LIST) )

[LanX]

in reply to Re: new keyword "size" to avoid scalar trap ? ( scalar @array != scalar(LIST) )
in thread new keyword "size" to avoid scalar trap ? ( scalar @array != scalar(LIST) )

I care less about the name than the functionality, could be also "count" or whatever suits.

I suppose "elems" is already known from ruby or perl6? So why not.¹

But² tobyinks and your suggestion w/o prototypes is considerably slower on large arrays.

  DB<106> use Time::HiRes qw(time)
 
  DB<107> sub elems { scalar @_ }
 
  DB<108> @a=(1..1e6);0
 
  DB<109> $t=time; $count = scalar @a; print time-$t
7.10487365722656e-05
  DB<110> $t=time; $count = elems @a; print time-$t
0.0554749965667725

Perl 5.10!

¹) Well the plural in "elems" somehow indicates a list to be returned.

²) as already said

[Laurent_R]

It is most probably the copying of the argument list (the full array) in the function call that takes this time difference.

Passing a reference to the array would probably solve the issue, but the syntax would become less obvious to use.

[Anonymous Monk]

No copying takes place :) however the same amount of scalars is aliased ;)

[LanX]

Thats why we need prototypes or a special C-implementaton.

according to the perlsub sub size (+;@) { } could be used, to call

 size @array

or

 size 1,2,3

but since I'm using 5.10, I can't test it...