global vs context variable

[luka8088]

On 11.12.2013. 10:53, QAston wrote:
> 
> This issue is probably nearly as old as programming itself.
> There are several sollutions already developed: dependency injection
> (requires complex configuration rules), manually passing deps as args
> (cumbersome), service locator or global variables.

Yeah, and it always keeps pooping right up!

> 
> Your sollution as far as I understand it relies on swapping a global
> variable when inside a context and restoring it afterwards. While this
> would be perfectly fine in environment where code is executed in OS
> threads, there will be a problem in the case of Vibe.d which uses
> fibers. But I guess the problem is solvable there aswell.

I was thinking about such issues and think they are all solvable. I
concluded that I should present this issues as simple and possible to
check out the general interest first.

> 
> Just to note - you have to bind to globals at some point - what if
> someone wants to swap writeln function whith his own (for example to
> call logger, or for whatever reason)? Or he may want to swap dbContext
> :).In my practice I make swappable only things I think I'll need to swap
> in future.

Yes. Not only that swapping would need to permitted but also only same
type values could be swapped. D makes sure of that.