On Wed, 15 Jun 2011 23:23:43 -0400, Ary Manzana <a...@esperanto.org.ar>
wrote:
On 6/15/11 8:33 PM, Steven Schveighoffer wrote:
On Tue, 14 Jun 2011 09:53:16 -0400, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
http://www.wikiservice.at/d/wiki.cgi?LanguageDevel/DIPs/DIP11
Destroy.
I put this as replies in several threads, but I'll throw it out there as
its own thread:
* You already agree that having the fetching done by a separate program
(possibly written in d) makes the solution cleaner (i.e. you are not
infiltrating the code that actually does compiling with code that does
network fetching).
* I think specifying the entire url in the pragma is akin to specifying
the full path of a given module on your local disk. I think it's not the
right place for it, the person who is building the code should be
responsible for where the modules come from, and import should continue
to specify the module relative to the include path.
* A perfect (IMO) way to configure the fetch tool is by using the same
mechanism that configures dmd on how to get modules -- the include path.
For instance -Ihttp://xxx.yyy.zzz/package can be passed to the compiler
or put into the dmd.conf.
* DMD already has a good mechanism to specify configuration and you
would barely have to change anything internally.
Here's how it would work. I'll specify how it goes from command line to
final (note the http path is not a valid path, it's just an example):
dmd -Ihttp://www.dsource.org/projects/dcollections/import testproj.d
1. dmd recognizes the url pattern and stores this as an 'external' path
2. dmd reads the file testproj.d and sees that it imports
dcollections.TreeMap
3. Using it's non-external paths, it cannot find the module.
4. It calls:
dget -Ihttp://www.dsource.org/projects/dcollections/import
dcollections.TreeMap
5. dget checks its internal cache to see if the file
dcollections/TreeMap.[d|di] already exists -- not found
6. dget uses internal logic to generate a request to download either
a. an entire package which contains the requested import (preferred)
b. just the specific file dcollections/TreeMap.d
7. Using the url as a key, it stores the TreeMap.d file in a cache so it
doesn't have to download it again (can be stored globally or local to
the user/project)
8. Pipes the file to stdout, dmd reads the file, and returns 0 for
success
9. dmd finishes compiling.
So if I have a library with three modules, a.d, b.d, c.d, which depend
on another library, I should put that pragma(importpath) on each of them
with the same url?
With the updated proposal (please see the DIP now), you can do -I to
specify the import path on the command line. Otherwise, yes, you have to
duplicate it.
Or maybe I could create a fake d file with that pragma, and make the
three modules import it so I just specify it once.
As long as the fake d file imports the files you need publicly, it should
be pulled in, yes. But the import pragma only affects imports from the
current file. I think that seems right, because you don't want to worry
about importing files that might affect your import paths. I look at it
like version statements.
-Steve
