Very good one! This is what I call unreadable...
You are using a propriety of die() I didn't know of...
die() can also be called with
a reference argument. If this happens to be trapped within
an eval(), $@ contains the
reference.
So after the eval() died $@
contains a reference to an array holding only one element,
which is a reference to an array containing the
string "Just another Perl hacker".
But what does the print() actually
print?
Let's cut the all thing in several bits:
first you must know that $#{@{${@}}} equals 0.
Here is why:
when you see $#a, this is the value of the last
array index (one less than the size of the array) of the
array @a.
@{${@}} is an array dereference. Since $@ is an
array holding only one value, the result is 0.
We now have to understand
${${${@}}[0]}[$#{${@{${@}}}[0]}]...
We recognize the underlined part as an index value. Let's
calculate it.
-
${${@}}[0] is the first element of the
array reference by $@ (which is another reference
to the array holding the string we want to print).
- In $#{${@{${@}}}[0]} the underlined
part is an array (dereferenced from $@).
The $#<array> notation will give us the
value of the last index of the array, which is 0.
With ${${${@}}[0]}[0], we
are almost there.
The underlined part is an array dereference, from which
we want the first element.
This element is "Just another Perl hacker". QED.
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