[sterlind]

so as an example, I've used priority queues a lot. you need them for Dijkstra.. apparently golang has a heap package which lets you push and pop `interface{}`. sure you can cast, and I guess people have to, but why couldn't Go just call `interface{}` object or any? the awkwardness of the convention suggests an unwillingness to accept failure.

[xh-dude]

Parametric polymorphism is a better fit for container types IMHO. There are some interesting notes here…

In Go prior to generics, interface{} is an escape hatch less frequently needed but not necessarily much safer than void*. Post generics, interface{} is suddenly more useful and will be aliased by ‘any’.

The way the std lib heap works in Go, an implementation doesn’t have to mention interface{}. Using the Go std lib solution is about satisfying a few interfaces, defining some methods for sorting and swapping over the element type. The use of interface{} is internal.

Go’s generics solution is going to have type constraints, which I think will be very familiar to some and probably new to others … So, the Go generics PQ should still require some constraints on elements, not ’any’thing will work. I’ve really enjoyed constraints in languages and it’s not quite natural in C++/Java, but Go’s interfaces already do some ‘constraint’ work conceptually and can be used as constraints in Go’s generics syntax. I’m interested to see how this plays out.

[jacobvosmaer]

>not necessarily much safer than void*

You can cast void* to anything you want. With interface{} you get a type check, either through an assertion or a panic. That is a big difference in safety.

[xh-dude]

Fair point. Maybe there are contrived cases that can get nasty (an interface{}-typed variable boxing a function is possible, not so with any non-empty interface ), but in practice the pathology would be ‘panic’ more than ‘here are the keys to the exploit kingdom’, if this is what you were thinking.

I was thinking more about silence where someone expected a greater degree of compile-time type safety than they really had, or relatedly e.g. the subtleties in JSON encoding / decoding where there is silent data corruption that could fall through the cracks - mostly I feel like I avoid these things by not using interface{}; I certainly did not grasp that without some experience with the language.