On 7/28/2018 11:06 PM, Nicholas Wilson wrote:
Then again I don't see any (non philosophical/compiler front end internal) issue why you can't reopen a namespace. D is supposed to be pragmatic, after all.
Consider if a template reopens a namespace and throws a few more overloads in it. Then, what's in the namespace is dependent on which expansions are done, in which order. Throw in the inevitable circular references. Do people write code like that? Sure as shootin', they do, and they demand that it work, and file lots of bug reports about the erratic behavior.
Next, consider a function body throwing a few more overloads in. Now, if the function body is compiled or not (and the compiler tries to avoid compiling bodies unless it has to) affects code that is outside of the function.
C++ is full of stuff like that. The difference is, when code fails in some bizarre way, programmers blame themselves and throw money at Scott Meyers to educate them on how to avoid writing such code. For D, they blame me.
The last time we fixed scope lookup to make it more complicated was with imports, and that took YEARS to sort out.
So I'm a little reluctant to add features that will result in a rat's nest of problems I can neither explain nor fix, then someone will add 4000 incomprehensible lines to fix 2 cases and add 5 or 6 bizarre regressions in the process and people complain the compiler is unstable. :-)
