Well, not really *that* criminal --

it's a non-empty list...

<INCORRECT>
lists in scalar/boolean context return the number of their elements.
</INCORRECT>;

Update: I humbly acknowledge the folly of the above statement.

Should be:

list assignment returns the number of elements.

End Update

Thus:

perl -e '$val = () = 0; print $val';
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prints 1 -- true!

lists in scalar/boolean context return the number of their elements.

Oh. Once again, trying to dispel the myth of that statement. Repeat after me:
• You can never have a list in a scalar context...
• You can never have a list in a scalar context...
• You can never have a list in a scalar context...
Now, what's really happening is that you have a list assignment operator in a scalar context, which is defined as having a return value of the number of elements copied across, while giving a list context to the right side.

In this case, the right side is a simple expression, which gets turned into a list of one element. So we get a "1" for the return value.

Once more, just so you remember:

• You can never have a list in a scalar context...

-- Randal L. Schwartz, Perl hacker

No, that's not true. Lists do not exist in scalar or boolean context.

$a = (3,2,1);
print $a;  # 1
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Read my article ("List is a Four-Letter Word") at my web site for stuff I'd rather not rewrite here.

perl -e '$val = () = (10,20,30); print $val'
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prints 3.

$_="goto+F.print+chop;\n=yhpaj";F1:eval

What these two gurus are trying to say is that there is a HUGE difference between lists and arrays. Please don't confuse them.

An array in scalar context returns the number of elements therein.