27 Apr 2014 , tagged: Go, Golang, Reading List

Golang Reading and Notes for April 2014

Last week I attended the Toronto Golang Usergroup Meetup and it was plenty of fun. If you’re in or near Toronto and like to dabble with Go, come out. Oh, and did I mention free pizza?

Notes

• Casting in Go is slightly different than in C related languages. Instead of a cast, you perform a type conversion:

    var myVariable SomeGenericType = ...
  
    casted, ok := myVariable.(MoreSpecificType)
    // ok is a bool
    if ok {
    	// Type conversion successful
    } else {
    	// myVariable does not implement MoreSpecificType
    }
  

• The range keyword when used with two return values does not return references, but rather copies. This had me struggle for a while as my code was not behaving as I thought it would. I had a slice of structs and was happily iterating over it:

    type Foo struct {
    	a string
    }
  
    func main() {
    	foos := []Foo{
    		Foo{a: "horray"},
    		Foo{a: "yeay"},
    	}
  
    	for i, value := range foos {
    		// This works because we directly access the struct stored
    		foos[i].a = "Changing the value" within the slice
  
    		// Won't work because value is a *copy* of the struct found in
    		value.a = "this won't work" the slice
    	}
  
    	for _, value := range foos {
    		println(value.a)
    	}
    }
  

  Executable snippet here. In retrospect it makes sense, Go always passes copies to functions. But initially I was puzzled as my loops wouldn’t properly update my structs.

  If you’re using reference types, that issue doesn’t arise though. Reference types deserve a post on their own, which I will write soon.

Go Reading List

• Comparing Go and Erlang: some interesting thoughts on shortcomings of Go, including that Go offers nil. This is an argument I’ve read about quite a few times now and is always along the lines of “Modern languages should not have a nil/null”. In addition this article
• Go Best Practices for Production Environments: lots of experience from the guys at Soundcloud about how they’re using Go. Covers development environment, logging, dependency management, and builds & deploys.
• By Peter Bourgon, the author of the previous post, a presentation Go Do on why Go.
• Blog post introducing Go Learn, a machine learning library in Go.
• Go’s power is in emergent behavior