4 ms·

Custom operators for all things ! or how to make your code base unmaintainable

sparkie 12y ago
They should put big intrusive warnings on operator overloads to discourage their use, like "Warning, you are using the complement operator for an operation which does not appear to be a complement. Don't do this!" (or alternatively, drop operator overloads from the language, because they are abused more often than not). I don't really see how `name =~ "somepat"` is any more readable or writable than something like `name.matches("somepat")`, which can be trivially added as an extension of String, and needs no special syntactic support. Something like this: extension String { func matches(pattern: String) -> Bool { return Regex.new(pattern).test(self) } }
- jonhohle 12y ago
  > They should put big intrusive warnings on operator > overloads to discourage their use, like… "Warning, you are using the addition operator to concatenate two Strings. Don't do this!", said no compiler, ever. Only C does the "right thing" with char*s or chars when using '+' ;-) In Swift, operator overloading requires no special syntactic support. Since it's a supported language feature, don't be surprised to see people use it.
jonhohle 12y ago
I've never understood this position. Why is a symbolic operator name so much more difficult to maintain than a name restricted to [a-zA-Z0-9_]? Over the last decade I've heard this repeated (and been stuck in languages which don't support operator overloading), and by chance, the very first project I chose to try to implement in Swift and I found a valid use for operator overloading (manipulating coordinates in a simple 3D renderer). foo = foo.add(bar) baz = baz.div(car) vs. foo = foo + bar baz = baz / car or even better: foo += bar baz /= car Unrelated to operator overloading, but taking some Objective-C 1.0 -> Swift resulted in 50% fewer lines of code (and I'm guessing ⅓ the total characters). edit: bug ;)
- sparkie 12y ago
  > I've never understood this position. Why is a symbolic operator name so much more difficult to maintain than a name restricted to [a-zA-Z0-9_]? Several reasons: It's not obvious what an operator does, whereas names are descriptive. Some operators are "obvious", because they're firmly ingrained into our culture - (+) for addition is an example, it's almost universally understood to mean that. On the other hand, where in tilde, ~, is it obvious that you meant to test if a string matches a regular pattern? It's only obvious to descendants of PERL, for the reason that Larry Wall decided arbitrarily to use it for such. If every programmer invented his own operators instead of using the common languages we share, we would get nowhere. Indeed, operator overloads are really useful when you use them the right way, as per your own example, but the flaw in allowing people to overload operators arbitrarily is that they abuse them to mean something unexpected - we all expect + to mean addition, but when it's used to concatenate two strings, it's easy to get confused as to why the hell somebody thought that was a good idea. A big hurdle is even figuring out what an operator means if you've never encountered it. Unless you have good IDE support to navigate to its definition, or a specialized search engine for searching your language, then a typical search is going to turn up naught. On the other hand, most search engines understand [a-ZA-Z]+. We could argue that using "+" for string concatenation "is obvious", at least to other programmers - but only because they've encountered such usage before. We can't reasonably expect to learn, recall, and fluently read arbitrary operators for any conceivable operation you can think of. Well, unless you're a fan of Control.Lens.Operators (http://hackage.haskell.org/package/lens-4.1.2/docs/Control-Lens-Operators.html http://hackage.haskell.org/package/lens-4.1.2/docs/Control-L...), then nobody else is going to read your code.
  - kbenson 12y ago
    Like everything, it's a trade-off. Here's an example of something I've been envious of Haskell about for a while: https://bitbucket.org/xnyhps/haskell-unittyped/wiki/Examples https://bitbucket.org/xnyhps/haskell-unittyped/wiki/Examples There's times where it really does make stuff much more readable. It's about finding and taking advantage of those times.
- kbenson 12y ago

They should put big intrusive warnings on operator overloads to discourage their use, like "Warning, you are using the complement operator for an operation which does not appear to be a complement. Don't do this!" (or alternatively, drop operator overloads from the language, because they are abused more often than not). I don't really see how `name =~ "somepat"` is any more readable or writable than something like `name.matches("somepat")`, which can be trivially added as an extension of String, and needs no special syntactic support. Something like this: extension String { func matches(pattern: String) -> Bool { return Regex.new(pattern).test(self) } }

jonhohle 12y ago
> They should put big intrusive warnings on operator > overloads to discourage their use, like… "Warning, you are using the addition operator to concatenate two Strings. Don't do this!", said no compiler, ever. Only C does the "right thing" with char*s or chars when using '+' ;-) In Swift, operator overloading requires no special syntactic support. Since it's a supported language feature, don't be surprised to see people use it.

jonhohle 12y ago

I've never understood this position. Why is a symbolic operator name so much more difficult to maintain than a name restricted to [a-zA-Z0-9_]? Over the last decade I've heard this repeated (and been stuck in languages which don't support operator overloading), and by chance, the very first project I chose to try to implement in Swift and I found a valid use for operator overloading (manipulating coordinates in a simple 3D renderer). foo = foo.add(bar) baz = baz.div(car) vs. foo = foo + bar baz = baz / car or even better: foo += bar baz /= car Unrelated to operator overloading, but taking some Objective-C 1.0 -> Swift resulted in 50% fewer lines of code (and I'm guessing ⅓ the total characters). edit: bug ;)

sparkie 12y ago
> I've never understood this position. Why is a symbolic operator name so much more difficult to maintain than a name restricted to [a-zA-Z0-9_]? Several reasons: It's not obvious what an operator does, whereas names are descriptive. Some operators are "obvious", because they're firmly ingrained into our culture - (+) for addition is an example, it's almost universally understood to mean that. On the other hand, where in tilde, ~, is it obvious that you meant to test if a string matches a regular pattern? It's only obvious to descendants of PERL, for the reason that Larry Wall decided arbitrarily to use it for such. If every programmer invented his own operators instead of using the common languages we share, we would get nowhere. Indeed, operator overloads are really useful when you use them the right way, as per your own example, but the flaw in allowing people to overload operators arbitrarily is that they abuse them to mean something unexpected - we all expect + to mean addition, but when it's used to concatenate two strings, it's easy to get confused as to why the hell somebody thought that was a good idea. A big hurdle is even figuring out what an operator means if you've never encountered it. Unless you have good IDE support to navigate to its definition, or a specialized search engine for searching your language, then a typical search is going to turn up naught. On the other hand, most search engines understand [a-ZA-Z]+. We could argue that using "+" for string concatenation "is obvious", at least to other programmers - but only because they've encountered such usage before. We can't reasonably expect to learn, recall, and fluently read arbitrary operators for any conceivable operation you can think of. Well, unless you're a fan of Control.Lens.Operators (http://hackage.haskell.org/package/lens-4.1.2/docs/Control-Lens-Operators.html http://hackage.haskell.org/package/lens-4.1.2/docs/Control-L...), then nobody else is going to read your code.
- kbenson 12y ago
  Like everything, it's a trade-off. Here's an example of something I've been envious of Haskell about for a while: https://bitbucket.org/xnyhps/haskell-unittyped/wiki/Examples https://bitbucket.org/xnyhps/haskell-unittyped/wiki/Examples There's times where it really does make stuff much more readable. It's about finding and taking advantage of those times.
kbenson 12y ago