[Distutils] Seeking the Essence of the Concept of an Egg
jeff at taupro.com
Thu Feb 28 11:46:57 CET 2008
In preparing for a tutorial on Python eggs, I'm wrestling with the *precise*
definition of a "Python egg". It appears to be a slippery term from the
"There are several binary formats that embody eggs, but the most
common is '.egg' zipfile format, because it's a convenient one
for distributing projects. All of the formats support including
package-specific data, project-wide metadata, C extensions, and
Ok, so what binary formats -other than- .egg files are actually eggs? I
figure RPMs, .debs, etc. are eggs, as long as they have an EGG-INFO
subdirectory and conform to certain basic structural rules.
"Eggs are pluggable distributions in one of the three formats
currently supported by ``pkg_resources``. There are built
eggs, development eggs, and egg links."
Hmmm, so it's not just binary distributions that can be eggs, but also
egg-links and development eggs. The concept of a "built egg" egg still
includes an RPM or .deb though.
"Python Eggs are the preferred binary distribution format for
EasyInstall, because they are cross-platform (for "pure"
packages), directly importable, and contain project metadata
including scripts and information about the project's
dependencies. They can be simply downloaded and added to
sys.path directly, or they can be placed in a directory on
sys.path and then automatically discovered by the egg
Well drat, so RPMs and .debs are -not- eggs, because you don't just place them
on sys.path directly to use them. Egg-links don't quite fit that definition
either, unless you look at them funny. So what -other- binary format could
that first paragraph be talking about that can be dropped onto sys.path and be
picked up by Python?
Python eggs are so very zen; you can only understand them by already
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