![]() By passing it around as an Implicit Context using implicit, it saves all that duplication and cleans up the code considerably. While there are only 4 copies of ec in this short snippet, in a larger file or codebase you could easily have dozens, hundreds or thousands of redundant copies. Biggest difference I see in the type tree is that 2.10.6 tried to cook the method parameters while 2.11.8 doesn't: 2.11. Without implicits you would need to pass it into each of those functions manually: val ec: ExecutionContext = .global Perhaps indirectly related to SI-6760 but overloaded method had different signature than Object.clone. map methods also need an ExecutionContext to run their callbacks. ![]() GetEmployee and getRole both require an ExecutionContext to run their asynchronous fetches, and the. This is something you could pass in manually, but is common enough that simply "not having to pass it everywhere" is itself a valuable goal.įor example, the standard library uses it to pass around an implicit ExecutionContext to every piece of code that needs to "run something asynchronously": implicit val ec: ExecutionContext = .globalĭef getEmployee(id: Int)(implicit e: ExecutionContext): Future = ?ĭef getRole(employee :Employee)(implicit e: ExecutionContext): Future = ? The most basic use of implicits is the Implicit Context pattern: using them to pass in some "context" object into all your methods. This is not going to be anywhere near an exhaustive list of the things you can do with implicits, but should hopefully provide a foundation that you can use when trying to use them yourself or understanding other people's code. Since there isn't that much published literature about design patterns in Scala, all these are names I just made up off the top of my head, so hopefully the names will make sense. This blog post documents some of those, specifically around the use of implicit parameters: Rather, you most often use implicits as a tool to help you implement one of a small number of patterns. You generally do not use implicits for the sake of using implicits, neither do you use implicits freely in all possible ways. ![]() However, implicits themselves are a pretty low-level feature. An implicit parameter is one that can be automatically inferred based on its type and the values in scope, without you needing to pass in the value of the argument explicitly, and an implicit conversion function converts one type to another automatically on-demand, without needing to call the function explicitly. "Implicits" - implicit parameters and implicit conversions - are a major feature of the Scala language. ![]()
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