1.py

# Proposal #1
#  This attempts to closely match the Gemfiles from Bundler, this might mean that
#   people would find it easier to pick up. However it could also mean that people
#   will think down of it as a "copy" and the differences might be noticed more since
#   The syntax is matched better.
source "https://simple.crate.io"
source "https://pypi.python.org/simple/"

dist "requests"
dist "Django", "~>1.4"
dist "pinax", git = "git://github.com/pinax/pinax.git", branch = "1.4"
dist "crate", path = "~/blech"
dist "test", group = "development"
dist "test2", group = ["development", "testing"]

group "development":
    dist "blah"

2.py

# Proposal #2
#  This proposal takes the ideas from a Gemfile, and makes them more "Pythonic".
#   Instead of creating a DSL, simple functions are used. This shares a lot of the
#   same benefits as #1 in that people might find it easier to pick up as some will
#   already know Gemfiles. An obvious negative is that it tends to be a bit more verbose
#   than #1.
source("https://simple.crate.io")
source("https://pypi.python.org/simple/")

dist("requests")
dist("Django", "~>1.4")
dist("pinax", git="git://github.com/pinax/pinax.git", branch="1.4")
dist("crate", path="~/blech")
dist("test", group="development")
dist("test2", group=["development", "testing"])


group("development",
    dist("blah"),
)

3.yml

# Proposal #3
# This proposal takes the power introduced via 1 and 2, but uses yaml to create a
#  (hopefully) easy to parse set of requirements. The given example makes heavy
#  use of inline style of declaration so that one line == one dependency. One area of
#  concern is how to handle the "default" group. It will need to exist somehow. As a simpler
#  way here the default group can be defined outside of a groups: tag, but the question remains
#  what should that tag be called?
sources:
  - https://simple.crate.io
  - https://pypi.python.org/simple/

require:
  - requests
  - [Django, ~>1.4]
  - [Pinax, {git: "git://github.com/pinax/pinax.git", branch: 1.4}]
  - [crate, {path: ~/blech}]
  - [test, {group: development}]
  - [test2, {group: [development, testing]}]

groups:
  development:
    - blah
  
  

So I'm definitely not following these discussions closely, but what is the actual solution going forward for non-universal dependencies? What is the solution for "I depend on XYZ on PyPy", and "ABC on windows", and "EFG" on python 2.6?

EDIT: (If not "just Python")