I'm not much of a fan of operator overloading anyway. But I thought it was a nice thought experiment, and again, maybe acceptable for oneliners.

I still tried to cheat the system and go around the "useless use [...] in voix context" by using <<= instead of << because $magic << "Value"; returns $magic itself so $magic <<= "Value"; works fine.
Except it failed when trying to turn this: $magic << "Value" << "Other value"; into $magic <<= "Value" <<= "Other value";, because << is a left associative operator and <<= is a right associative one. Meanig you've just turned ($magic << "Value") << "Other"; into $magic <<= ("Value" <<= "Other");. Whoops.

So yes, the lesson is don't add new semantic to operators kid (yup, I'm looking at you C++).

Operator overloading is great, I'm not against it per se.

But it's a two-edged sword which should be handled with care.

Overloading an operator because it looks like another syntax is not a good idea ( here >> )

A good example for overloading are set operations, because the logic is "compatible".

• X * Y intersection
• X + Y join
• X - Y difference
• - X complement
I could also attempt to use the logical && family but short circuiting could sabotage it.

Bitwise ~ | & ^ etc. might be another option tho ... and the analogy between sets and bit vectors might help.

update

Found Set::Scalar which has a good set of overloaded operators.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

A good example for overloading are set operations, because the logic is "compatible".

• X * Y intersection
• X + Y join
• X - Y difference
• - X complement

I don't see how the logic is compatible, unary - as complement means X - Y is different from X + (-Y). And there's just no relation between * and + anymore. At least with + for concatenation (which I already don't like much), you can have STRING * 3 to be equivalent to STRING + STRING + STRING.

And actually now that I think of it, the best operator to overload to append to a file is .=. With the dot you have both the append and string semantic, and the = makes it ok for the operation to have an effect on the left operand. And it makes chaining more consistent:
file("path") .= "First string" . "Second string";