https://developer.apple.com/library/prerelease/ios/documenta...
According to the documentation you can declare an operator composed by an arbitrary list of this characters "/ = - + * % < > ! & | ^ . ~". You can recreate C++ stream operators (<<, >>), Ruby combined comparison (<=>), and so on.
For example one can define operators called <>, =<, =>, and !=
You can do interesting stuff with pre- and suffix operators, too. For example, the XML comments <!-- and --> could be a prefix- and suffix operator pair.
Also, you could define operators that look conspicuously like comments, at least to some of your readers.
[disclaimer: I don't have access to the code; I just read the documentation. That documentation seems to imply that // starts a comment _and_ can be used to implement a custom operator. Even if that isn't possible (fairly likely, I would say, you can still try using --- or /// as your operator]
I checked: neither // nor /// can be used as operators (syntax error: they both just start a comment). All your other examples work, but I would say those mean the author is intentionally trying to trick me. Or he’s writing a clever DSL, but that line is very fine and treacherous.
Some other food for thought:
a = b-- // !z
x = y--// ! z
a = b - 1
A variation:
x+ - 3
x + -3
Also, the docs do not seem to discuss line breaks inside statements. If they are legal, you can do:
x+
-3
x+{space}
- 3
> Operator symbols are formed from one or more symbol characters, as defined above …
where 'above' is:
symbol -> ascSymbol | uniSymbol<special | _ | : | " | '>
ascSymbol -> ! | # | $ | % | & | * | + | . | / | < | = | > | ? | @
| \ | ^ | | | - | ~
uniSymbol -> any Unicode symbol or punctuation> (--|) = (+)
When I talk to myself while coding, I have no name to say out loud.
I have nothing but a picture, when I try to remember the operator.
http://stackoverflow.com/questions/7746894/are-there-pronoun...
http://stackoverflow.com/questions/3242361/haskell-how-is-pr...
I got to this by Googling for the 'fish' operator, to which I vaguely remembered seeing a reference:
http://www.reddit.com/r/haskell/comments/c262b/the_fish_oper...
In languages that don't allow you to overload operators at all, the alternative is to use explicit function syntax. That can sometimes be a short path unreadable to code that's littered with pyramids of doom.
In languages that only allow you to overload existing operators, you end up with monstrosities like C++'s << and >> operators, which overload the bit-shift operators with new and completely unrelated semantics. It's that kind of shenanigans that give operator overloading such a bad name.
It is both a blessing and a curse, as far as potential for abuse is concerned.
You pointed out the downside of arbitrary operator names. The downside of operator overloading on fixed operator names is that you are limited in your choice of operators, so instead of choosing a more distinct operator, you sometimes have to go with things that are kind-of-the-same, or maybe not close at all. And instead you also have the problem of misleading people, for example by using the +-operator for set union, while the reader thinks you are adding together numbers.