{"id":97426,"date":"2020-11-24T16:33:13","date_gmt":"2020-11-24T15:33:13","guid":{"rendered":"https:\/\/blog.jetbrains.com\/?post_type=go&p=97426"},"modified":"2021-05-06T07:30:11","modified_gmt":"2021-05-06T06:30:11","slug":"experimenting-with-go-type-parameters-generics-in-goland","status":"publish","type":"go","link":"https:\/\/blog.jetbrains.com\/en\/go\/2020\/11\/24\/experimenting-with-go-type-parameters-generics-in-goland","title":{"rendered":"Experimenting with Go Type Parameters (Generics) in GoLand"},"content":{"rendered":"

In today’s article, we will experiment with generics in Go, and their latest form, Type Parameters<\/em>.<\/p>\n

Before we start, let’s take a quick look at the proposal’s history.<\/p>\n

History of generics in Go<\/h2>\n

Generics have been some of the most desired language features since Go’s inception. While the Go team never explicitly rejected them, they also did not have a good way to solve the problem of introducing generics to the language without making Go look and feel less Go-like.<\/p>\n

That was until August 2018, when the Go team introduced the notion of Contracts<\/a> and started a big discussion with the community<\/a> about how generics could look and work in Go.<\/p>\n

Based on overwhelming feedback from the community, the Contracts<\/em> proposal evolved and was modified until mid-2019. After a careful analysis of the proposal, it was determined that contracts are too similar to interfaces. So Contracts<\/em> were dropped in favor of interfaces with a bit of twist, which we’ll return to later. Instead, a new proposal<\/a> was developed that simplified the learning curve and usage of Type Parameters<\/em> in Go.<\/p>\n

Another year has passed since those last discussions of Type Parameters, and this year’s GopherCon US<\/a> provided a better insight into how generic code could look and work in Go.<\/p>\n

Enough with the history for now. Let’s start writing some generic code for Go!<\/p>\n

Using the Generics Go SDK in GoLand<\/h2>\n

Before we can start coding, we’re going to need a special version of Go, and we’ll have to compile it ourselves.<\/p>\n

For the purposes of this article, I’m using GoLand 2020.3.<\/p>\n

Let’s use the Get from VCS<\/em> action and select the Go repository https:\/\/go.googlesource.com\/go<\/a>. We clone that into a folder anywhere on our computer outside of the GOPATH<\/em> and give the folder a name: go-mainline<\/em>.<\/p>\n

Since we are compiling Go ourselves, we need to perform a few more steps than we would for a regular project.<\/p>\n

First, we’ll use the Branches<\/em> feature, Ctrl+Shift+`<\/em>, search for the dev.go2go<\/em> branch, then we select the Checkout<\/em> option.<\/p>\n

\"Clone<\/p>\n

Next, we’ll configure some environment variables and settings for the IDE:<\/p>\n