"List.add(otherList) <-- what does this do? Why, compared to operators, would a function name be any better than an operator? Mathematics are part of computer science, and denying basic operators for a reason like "because someone might misuse them" is like denying functions because someone may implement a sum() and call it lcm() (and then we're back to goto land). You're confusing a programmer's error (bad choice of a name/operator function) with a language feature. Just because people can write bad code it does not mean we should disallow them to write great code."
Honestly, it's about time the Java crowd stops with the mantra and starts thinking from themselves. Or at least, learn why the reason you hate operator overloading is fallacious.
It is just symbolic names, like doing abstract mathematics with letters instead of numbers.
Except for C, Java and Go, all the remaining mainstream languages allow for symbolic names in the functions/methods.
I never understood what was the big deal.
Yeah until you have to work with java's Bignums one day, then you start wanting to choke people to death.
Some people seem to think that if they don't use, then it doesn't matter. In many business applications, you don't even need floating point (you just transfer data to the database and back), anyway.
Are floats and doubles "little features"?
In computer graphics, you need lots of floating point calculations. Are ints and longs "little features"?
In embedded software, you usually don't want to use resizable strings (C doesn't even have this feature built-in), because reallocations are expensive or unavailable. Are resizable strings (or containers) "little features"?
Different programs have different needs. If you haven't stumbled upon a good use case, doesn't mean that it's useless.
Then you have to take into account a few other criteria, such as [1] internal coherence in the language, [2] difficulty in implementation (and explaining to others) [3] what your target audience is, and what they want, [4] what competitors are doing.
I think full operator overloading would hurt [2], but special-casing Bignums would not hurt [1], [2] at all (as I said, JSP EL already have +,-,*,/, etc. , String already have +, +=).
[3] This is what this thread is all about, no need to repeat :-D
And [4]... Well in this case Java is really playing catch up.
It doesn't really matter, some people see classes/objects as a minor feature too. I agree with him: operator overloading is not a minor feature and it's probably one of the reasons I am not very fond of Java.
There's an axiom to be found somewhere there. If it's a hill, someone will be willing to die on it.
I have never heard a convincing theory of why some language communities were careful in their use of operators, whilst others went overboard. In the absence of such a theory, it's a risky feature to add.
I'd prefer if that option stays off the table. Given that java users are on ides, autocompletion makes an api call a one character effort anyway and saves us from tons of stupid operators.
I think it depends a lot on the languages. Operator overloading is easy and common in Python, but in my (limited) experience, it's used to create new classes which respond to existing operators with existing semantics, e.g. to make new number classes. For this, it's great. There's no particular reason the types built-in to the language should get special treatment for operators, as long as programmers can resist the temptation to be idiots.
In Python, it's called "special method attributes" and they can do a lot more than just create classes. The __eq__ attribute returns a straight boolean for example in response to the "==" operator. And yes, by the way, you actually can accidentally alter attributes in the calling and callee objects if you aren't careful.
Do you have any data to prove such assertions? A C++ STL operator chosen more than a decade ago is not enough statistical data for one to have such a narrow-minded vision and say these bold statements. Maybe you need to check all the nice C++ libraries that make use of operator overloading.
A powerful new feature is introduced in a niche language, and novices abuse it. The feature gets a bad reputation. Yet eventually, as new languages adopt it, the community learns how to use it and how not to use it, and people become accustomed to it, and come to agree that it's not such a bad thing.
I'd say that's happened, to some degree, with garbage collection and lambda expressions. We seem to be in the middle of the process with operator overloading, and still in the early stages with Lisp-style macros (I can hope, anyway :-).
With C++, you can only overload the built-in symbolic operators. This means instead of choosing the best symbolic name to use as an operator you're forced to re-purpose some built-in operator like "<<". In Scala you can pick any name or symbol you want.
Conversely, there was an XML library for Scala posted on Reddit about a year ago that used things like <:<, <<? and <> as method names; clearly the freedom to concoct your own symbolic names is far more open to abuse than the oft-maligned C++ mechanism.
cout << x & y;
cout << (x & mask) != 0;
cout << boolVar ? "Yes" : "No";
And I don't buy the fact that << is somehow off limits because it's used for bitshift; the domain of usage is usually disjoint, although one would have to squint to grok the outputting of a bitshifted value to a stream - but how frequent is that?
Yes the << notation isn't perfect, but it is much nicer than named functions (and certainly superior to < (which Stroustrup initially considered)!). Adding arbitrary operators to the language would have required mechanisms to define associativity and precedence, which would have added a weight of complexity disproportionate to the reward.
cout << string << " and " << otherstring << endl;
cout.write(string).write(" and ").write(otherstring).write(endl);
Which I personally never had a problem with.
It's an example. Do you dispute that? It's classic. That's subjective, and I claim it by raw assertion. That's it.
Given these limitations, and the fact that most languages have relatively few built-in operators to choose from, I find that just operator overloading isn't enough. You really want the ability to define new operators as well. That's something Java (and C#, and C++, and many other languages) would really benefit from.
This is getting into blessing vs. curse territory, though. On the one hand, used well, a custom operator might enhance the benefits of allowing operator overloading in the first place. If your code is mathematical, you have an extended character set available, and you have good coding standards and keyboarding skills to match, then matching the operators/notation in the code to any related mathematical documentation has obvious advantages.
On the other hand, there are only so many obvious symbols available on most keyboards. Once those run out, you can resort to those extended characters, but they might not always be so unambiguous: most of us would recognise less-than-or-equal, but was that an empty set or just a slashed zero in the font Bill was using? The alternative is to start combining symbols, which again might make sense if say [[ ... ]] looks like whatever mathematical notation is standard in your field, but isn’t so great if you go all Haskell and define more-or-less every combination of three non-alphanumerical symbols in the universe to have some subtly different meaning... including from the same combination of symbols in the other library you’re using five lines later.
With the everyday operators that everyone programming Haskell will learn very early, I agree it’s not a significant problem. Familiarity will surely overcome any lack of intuitive meaning very quickly. The same applies if you’re using “made up” operators but they reflect some intuitive syntax or conventional notation in whatever field you’re working in. In all of these cases, having a concise notation for frequently occurring concepts is surely a benefit, other things being equal.
However, as you start to represent more specialised or esoteric concepts, I wonder whether there are diminishing returns and increasing risks. For example, I think it is good general advice that identifiers in code should be pronounceable, but how do you pronounce $$!? For that matter, did I just write a $$! operator and a question mark, or a $$ operator and an informal confusion/sarcasm mark?
Here’s a Stack Overflow discussion I thought was relevant:
http://stackoverflow.com/questions/7746894/are-there-pronoun...
Without any restriction, except for a few basic ones.
multi infix:<plus>(Int $a, Int $b) {
return $a + $b;
}
multi infix:<plus>(Str $a, Str $b) {
return $a ~ $b;
}
say 10 plus 4;
# 14
say "foo" plus "bar";
# foobarhttps://github.com/rakudo/rakudo/blob/nom/src/core/Int.pm#L1...
NQP in that link is "Not Quite Perl", a subset of the language which is the what actually needs to be implemented to support Perl 6. This is what's almost done being ported to Java. Again, for Rakudo, which is one implementation.