module hijacking

[Andrei Alexandrescu]

Steven Schveighoffer wrote:
> On Sun, 01 Nov 2009 01:28:56 -0400, Andrei Alexandrescu 
> <SeeWebsiteForEmail at erdani.org> wrote:
> 
>> I ran the following experiment:
>>
>> mkdir deleteme
>> cd deleteme
>> mkdir std
>> touch std/algorithm.d
>> echo 'import std.algorithm; void main(){int a, b;swap(a,b);}' >main.d
>> dmd main
>>
>> The attempt to compile main fails with "undefined identifier swap", 
>> which means that the module I defined in the current directory 
>> successfully hijacked the one in the standard library.
>>
>> The usual D spirit is that a symbol is searched exhaustively, and 
>> attempts at hijacking are denounced. In the module cases, it turns out 
>> that an entire module can successfully hijack another.
>>
>> Walter and I are ambivalent about this. There has been no bug report 
>> so it seems like people didn't have a problem with things working as 
>> they are. But maybe they never hijacked, or maybe some did hijack.
>>
>> Question: should we change this?
> 
> No.  This is completely the opposite of hijacking.  I would consider it 
> hijacking if I had a project with a blah/file.d and the standard library 
> added a blah/file.d that overrode *my* file.
> 
> -Steve

The opposite of hijacking would be if any duplicates found would be an 
error.

Andrei