> 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-L...), then nobody else is going to read your code.
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-L...), then nobody else is going to read your code.