referencing slices - love that DWIM

I was tinkering with some code tonight and realized a clean way to solve a problem was to pass an array of references to a sub. Problem was the entities I wanted references to were being obtained as a slice of an array. So I tried what seemed to me to be the obvious thing:

my @sliceRefs = \@array[4, 5, 9];
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and what do ya know? It just worked!

After I had tried the construct and it worked I had a vague memory of reading about it somewhere, but I sure can't find it now. It's not in the slice section in perldata and I can't find anything in perlref. Not that it matters. DWIM rules, but I'd be interested to find where it is documented.

Oh, you want to test it for yourself? Try:

my @array = (1 .. 10);
my @sliceRefs = \@array[4, 5, 9];

${$sliceRefs[2]} = -10;
print "@array";
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Perl is environmentally friendly - it saves trees

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Re: referencing slices - love that DWIM by BrowserUk (Patriarch) on May 17, 2008 at 11:11 UTC
See subsection 2 of perlref:Making references where it says: As a special case, \(@foo) returns a list of references to the contents of @foo, not a reference to @foo itself Just for fun try: `print "$_" for \( %{{a =>1}}, @{[1..3]}, "fred" );; HASH(0x2251b8) ARRAY(0x194a9f4) SCALAR(0x194aaa8)` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l]
Re^2: referencing slices - love that DWIM by GrandFather (Saint) on May 17, 2008 at 11:59 UTC
With the implication (extrapolated from the perlref quote) that \ notices that it is operating on a list and generates a list of references rather than a reference to list. I had a feeling that I'd seen something more explicit than that, although the quote from the docs does shed a some light on why it does what it does. Perl is environmentally friendly - it saves trees	[reply]
Re^3: referencing slices - love that DWIM by almut (Canon) on May 17, 2008 at 12:42 UTC
... rather than a reference to list I think there is no such thing as a reference to a list, because a list - in contrast to an array - is not internally represented in a way that it could be referenced in its entirety...	[reply]
Re^4: referencing slices - love that DWIM by syphilis (Archbishop) on May 17, 2008 at 13:35 UTC
Re^5: referencing slices - love that DWIM by Fletch (Bishop) on May 17, 2008 at 13:39 UTC
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Re^5: referencing slices - love that DWIM by almut (Canon) on May 17, 2008 at 14:15 UTC
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Re^5: referencing slices - love that DWIM by ysth (Canon) on May 18, 2008 at 05:57 UTC
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