Re: [MacPerl] Coding style

[Chris Nandor <pudge@pobox.com>]

At 08.26 -0500 1999.02.04, Emmanuel. M. Decarie wrote:
>myFunc(\@global);
>
>or
>
>@global = myFunc(\@global);

The problem is that the latter is slower.  Readability is good, but if
@global is sufficiently large, it can be quite slow.  Frankly, though, I
have no problem with the first one insofar as readability goes.  I would
look at the latter and say "why?".


>My understanding at the moment is that when you pass by reference an array
>or a >>>>>>>hash, there is nothing to show in the params that the
>function have the
>>>>>>>right to make changes to the original.

Sure.  It is implicitly understood.  If you don't want changes made to your
data, then don't pass a reference, or pass a copy of the data.

@newdata = myFunc([@global]);

That creates a reference to a copy of the data.  Of course, if @global
contains references as elements, those passed to myFunc still refer to the
original data.  You can also do something like:

use Data::Dumper;
@newdata = myFunc(eval Dump \@global);

Which will totally unpack @global into a string, which when passed to eval
will result in a reference to a data structure identical to [@global], but
without any common references.  You could also do that in your subroutine:

use Data::Dumper;
@newdata = myFunc(\@global);

sub myFunc {
  my $newdata = eval Dump shift;

}

--
Chris Nandor          mailto:pudge@pobox.com         http://pudge.net/
%PGPKey = ('B76E72AD', [1024, '0824090B CE73CA10  1FF77F13 8180B6B6'])

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