I have a feeling we are not using the same terms as having the same meaning.

When I return an lvalue, in my mind, I'm returning the address of an object so that the compiler/interpreter can put something in it (has happens to the left side of an assignment).

Vs. if I return an rvalue, In my terminology, I'm only returning the value that was in that address -- so the compiler/interpreter can't assign a new value into the variable location.

If I return an lvalue, the compiler can store a new value. But it can also propagate that value to another lvalue. No problem: I don't care. What I care about is detecting that my lvalue sub has been assigned to (whether or not the value changes is irrelevant).

The rvalue context I would detect in a statement like: 

if ($p->url) {...}

[download]
would allow me to return an actual value and not a tied var.

It's the 'lvalue' case where I need to presume that the value in 'url might change, and thus return a more expensive (ex. tied) version so I can update the url's component values.

I don't see how that is problematic.

In reply to Re^6: can sub check context for lvalue vs rvalue context? by perl-diddler
in thread can sub check context for lvalue vs rvalue context? by perl-diddler

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