Valid usages of implicit parameters?

This is very much a fine use case. I actually recommend this when scope determines the parameter to use. It provides an elegant way to pass some sort of context into a Plugin class so that utility functions will use the context.

For example: trait Context object UtilityLib { def performHandyFunction(implicit x : Context) : SomeResult = ... } trait Plugin { def doYourThing(implicit ctx : Context) : Unit } class MyPlugin extends Plugin { def doYourThing(implicit ctx : Context) : Unit = { UtilityLib. PerformHandyFunction } } SomePluginAPI. Register(new MyPlugin) You can see an example in a database migration system I was toying Check out the Migration class and its MigrationContext.

This is very much a fine use case. I actually recommend this when scope determines the parameter to use. It provides an elegant way to pass some sort of context into a Plugin class so that utility functions will use the context.

For example: trait Context object UtilityLib { def performHandyFunction(implicit x : Context) : SomeResult = ... } trait Plugin { def doYourThing(implicit ctx : Context) : Unit } class MyPlugin extends Plugin { def doYourThing(implicit ctx : Context) : Unit = { UtilityLib. PerformHandyFunction } } SomePluginAPI. Register(new MyPlugin) You can see an example in a database migration system I was toying.

Check out the Migration class and its MigrationContext.

Yes, I can see how this is useful. The use case that prompted the question is sort of along those lines, although I didn't think of the word "context"... – huynhjl Nov 11 '10 at 0:43.

It doesn't really look like an idiomatic use of implicits, which tend to be suited for type classes and dependency injection. There's absolutely no point in passing about a class with no members... It's also more common to define an implicit val or object of type I before making the call to (new B). Foo Having said all that, you supplied an obviously a very abstract example.So it's not too hard to imagine a reasonable use-case for implicits that follows a similar pattern.

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