Imports in DWT

[Ary Borenszweig]

Ty Tower escribió:
> Was it java that had
> 
> import dwt.graphics.*;
> and
> import dwt.graphics.Colour,Font,Cursor;
> 
> this saved a lot of typing. Can it not be done here? 

My guess is that it is not allowed in D for performance reason. In Java, 
say you have:

---
package some.package;

import foo.*;

class SomeClass {
   Bar b;
}
---

Now, to find Bar, you have to look for a file Bar.java in the directory 
foo in the classpath, or in the current package. If neither of these 
exist (very rare), then the compiler has to search in each java file in 
the current package for a top-level class named Bar (there can be only 
one top-level public class in a java file, and the name must be the same 
as the class). You can see how fast lookups are in Java because of the 
way it is designed.

In D, if you have

import foo.*;

Bar b;

the compiler will have to parse each file in the foo package, searching 
in each of them for a public symbol called Bar. Not only that, but it 
has to performe semantic analysis in each of them to resolve 
compile-time stuff and see if Bar is actually being generated in 
compile-time. So... a huge compilation performance impact.

(BTW, that's the reason why I hate "all" imports)