New `depends_on :python` Dependency.
New `depends_on :python3` Dependency.
To avoid having multiple formulae with endings -py2 and -py3,
we will handle support for different pythons (2.x vs. 3.x)
in the same formula.
Further brewed vs. external python will be transparently supported.
The formula also gets a new object `python`, which is false if
no Python is available or the user has disabled it. Otherwise
it is defined and provides several support methods:
python.site_packages # the site-packages in the formula's Cellar
python.global_site_packages
python.binary # the full path to the python binary
python.prefix
python.version
python.version.major
python.version.minor
python.xy # => e.g. "python2.7"
python.incdir # includes of python
python.libdir # the python dylib library
python.pkg_config_path # used internally by brew
python.from_osx?
python.framework?
python.universal?
python.pypy?
python.standard_caveats # Text to set PYTHONPATH for python.from_osx?
python.if3then3 # => "" for 2.x and to "3" for 3.x.
Further, to avoid code duplication, `python` takes an optional
block that is run twice if the formula defines depends_on
:python AND :python3.
python do
system python, 'setup.py', "--prefix=#{prefix}"
end
Read more in the Homebrew wiki.
Rationale: "prune" is slow, does not need to be run as often as
"cleanup", and is potentially destructive to things like empty
directories that Homebrew did not create. Thus we should let users run
`brew prune` only when they wish to, while still being able to use `brew
cleanup`.
ClosesHomebrew/homebrew#19863.
It doesn't really make logical sense that this method returns both the
fetched path (or sometimes nil!) and the downloader, so just return the
path (again, or nil!) and callers that want the downloader can ask for
it separately.
It is possible for the object returned by Formula#version to be a
subclass of Version with special behavior, so we want to use that for
the comparison.
