Well, its easy to demonstrate there is only one call made. So what now?

I think the easiest way to think of it, is that the function returns an lvalue to the calling context; and has no say or knowledge of how that lvalue is used there.

And in reality, that is exactly what happens:

{ my $X = 12345; sub x :lvalue { $X } };;
print x();;
12345

$r = \x();;
print x();;
12345

$$r = 456;;
print x();;
456

[download]

Think of a function returning a reference. It does not know and cannot influence whether that reference will be used to read the referent value, or assign a new value to it.

This is analogous; thus even if you knew what the context was, it would not benefit you to know. (Also why :lvalue never made it off the 'experimental' list.)

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In reply to Re^3: can sub check context for lvalue vs rvalue context? by BrowserUk
in thread can sub check context for lvalue vs rvalue context? by perl-diddler

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