Named multi-imports

[jmh530 via Digitalmars-d]

On Tuesday, 15 August 2017 at 20:33:18 UTC, Johnson wrote:
>>
>> Or instead of a new language feature, the gtk-d guys could 
>> have package files ;)
>
> But then that only helps with one specific instance. D is full 
> of language features, I do not see why everyone is so against 
> them. Without them, D would be empty, nothing, and no one would 
> use it. Adding language features should be see as something 
> good, cause without them, we wouldn't get anywhere.

In the past, I've thought it would be convenient to have 
something like

import io = std.stdio : writeln, write;

and allow someone to write

io.write("foo");
io.writeln("bar");

though I don't know if that causes any kinds of problems to 
implement.

That being said, the code you refer to above probably could be 
simplified quite a bit with mixins. I just did a simple version, 
but I imagine it could be extended. It also might be even easier 
to accomplish when static foreach is in the language, that would 
you can just loop through the LowLevels to accomplish it. Some 
kind of hierarchy to the HighLevels/MidLevels/LowLevels would 
also need to be established.

import std.meta : AliasSeq;

alias LowLevels = AliasSeq!("writeln", "write");

template GenImport(string TopLevel, string MidLevel, string 
LowLevel)
{
     const char[] GenImport = "import " ~ TopLevel ~ "." ~ MidLevel
                                                        ~ " : " ~ 
LowLevel ~ ";";
}

mixin(GenImport!("std", "stdio", LowLevels[0]));
mixin(GenImport!("std", "stdio", LowLevels[1]));

void main()
{
     write("foo");
     writeln("bar");
}