Dereferencing Subroutine Arguments

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

@an_array=(1,2,3,4,5,6,7);
&routine(\@an_array);

sub routine
{
  $ref=$_[0]; print @$ref; # That works
# print (@($_[0]));        # This would produce a compilation error!
  print @$_[0];            # And this doesn´t print anything!
}
[download]

WHY?

Comment on Dereferencing Subroutine Arguments Download Code

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Re: Dereferencing Subroutine Arguments by merlyn (Sage) on May 17, 2000 at 20:16 UTC
The canonical form of a dereference is to take the normal form: `@FOO` [download] and replace the word (here `FOO`) with a block returning the reference: `@{$a[0]}` [download] Only when the braces enclose a simple scalar variable (like `$x`) can you drop the braces. You don't have a simple scalar here, so the braces must remain on.	[reply] [d/l] [select]
Re: Dereferencing Subroutine Arguments by davorg (Chancellor) on Jun 21, 2000 at 12:47 UTC
Your second example, `(@($_[0]))` doesn't work because you're surrounding the reference with 'round' brackets, not 'curly' brackets.	[reply] [d/l]