The new std.process is ready for review

[js.mdnq]

On Sunday, 24 February 2013 at 00:25:46 UTC, Jonathan M Davis 
wrote:
> On Saturday, February 23, 2013 16:09:43 H. S. Teoh wrote:
>> BTW, is "std.process2" just the temporary name, or are we 
>> seriously
>> going to put in a "std.process2" into Phobos? I'm hoping the 
>> former, as
>> the latter is unforgivably ugly.
>
> In previous discussions, it was agreed that future replacement 
> modules would
> simply have a number appended to them like that (e.g. std.xml2 
> or
> std.random2). I don't think that that decision is irreversible, 
> but unless
> someone can come up with a much better name, I'd expect it to 
> stick, and it
> has the advantage of making it very clear that it's replacing 
> the old one.
>
> - Jonathan M Davis

That is a really really really bad idea! There are much better 
versioning methods out there.

import "std.process"; // uses latest version by default or file 
name exact match
import "std.process"[3 > ver >= 2]; or
import "std.process"[hash == hashid];

would be a better way. Module file names could have attached 
versioning info similar to how MS does it.

process.hash.versionid.otherattributes

The attributes are matched only if they are used, else ignored. 
Hence

process.hash.version.otherattributes.d
process.d

would be logically identical(and throw an error if in the same 
dir and no attribute matching used) but one could specify 
attribute matching to narrow down the choice. (or the latest 
version could be used by default and a warning thrown able 
multiple choices)


This allows one to keep multiple versions of the same module name 
in the same dir. It helps with upgrading because you can easily 
switch modules(one could set global matches instead of per 
module).

One could also have the compiler attach the latest match on the 
import so each compilation uses the latest version but it does 
not have to be specified by the user. When the user distributed 
the code it will have the proper matching elements in the code.

e.g.,

import "std.process"[auto]; // auto will be replaced by the 
compiler with the appropriate matching attributes. Possibly 
better to specify through a command line arg instead.

Another thing one can do to help is to have the compiler 
automatically modify the source code to include what module it 
was compiled with by hash and or version.

When the code is recompiled a warning can be given that a 
different version was used.