$ perl -e 'tied( sub {}->() )'
    Can't modify non-lvalue subroutine call at -e line 1.

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My question is: Who's trying to modify anything?

If I were reading this, my reaction would be “You tie variables, not values, so it doesn't make sense to test the result of a subroutine call using tied” (I tried it in a fit of optimism anyway); but my question is not so much why this approach doesn't work as why I get an error about an attempted modification when none exists. Is tied doing something bizarre internally like trying to assign to its argument and seeing if a STORE method fires?

(On a presumably much simpler note, I don't see why 

$ perl -e 'tied sub {}->()'
    Can't modify reference constructor in tied at -e line 1, near "})"

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parses differently. According to perlop, -> is higher in priority than anything but terms and list operators. As near as I can tell from perlfunc, tied isn't a list operator. I don't know if it's a ‘term’ because I'm not really sure what a ‘term’ is. :-)

UPDATE: As tye pointed out in the Chatterbox, perl -e 'tied sub {}->()' doesn't actually produce that error. It was all a dream!)

In reply to tied, or modified? by JadeNB

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