Traits 3.0 released!

I am very pleased to announce that Traits 3.0 has just been released!

All Traits projects have been registered with PyPi (aka The Cheeseshop)
and each project’s listing on PyPi currently includes a source
tarball. In the near future, we will also upload binary eggs for
Windows and Mac OS X platforms. Installation of Traits 3.0 is now as
simple as:

easy_install Traits

The Traits projects include:

The Traits project is at the center of all Enthought Tool Suite
development and has changed the mental model used at Enthought for
programming in the already extremely efficient Python programming
language. We encourage everyone to join us in enjoying the productivity
gains from using such a powerful approach.

The Traits project allows Python programmers to use a special kind of
type definition called a trait, which gives object attributes some
additional characteristics:

  • Initialization: A trait has a default value, which is
    automatically set as the initial value of an attribute before its first
    use in a program.
  • Validation: A trait attribute’s type is explicitly declared. The
    type is evident in the code, and only values that meet a
    programmer-specified set of criteria (i.e., the trait definition) can be
    assigned to that attribute.
  • Delegation: The value of a trait attribute can be contained either
    in the defining object or in another object delegated to by the trait.
  • Notification: Setting the value of a trait attribute can notify
    other parts of the program that the value has changed.
  • Visualization: User interfaces that allow a user to interactively
    modify the value of a trait attribute can be automatically constructed
    using the trait’s definition. (This feature requires that a supported
    GUI toolkit be installed. If this feature is not used, the Traits
    project does not otherwise require GUI support.)

A class can freely mix trait-based attributes with normal Python
attributes, or can opt to allow the use of only a fixed or open set of
trait attributes within the class. Trait attributes defined by a classs
are automatically inherited by any subclass derived from the class.

5 thoughts on “Traits 3.0 released!

  1. avatarteki

    Missing dependency:

    $ easy_install TraitsGUI
    Searching for TraitsGUI
    Best match: TraitsGUI 3.0.0
    Processing TraitsGUI-3.0.0.tar.gz
    Running TraitsGUI-3.0.0\ -q bdist_egg –dist-dir c:\appdata\local\temp\easy_install-\TraitsGUI-3.0.0\egg-dist-tmp-rv50xh
    Adding traitsgui 3.0.0 to easy-install.pth file

    Installed c:\python25\lib\site-packages\traitsgui-3.0.0-py2.5.egg
    Processing dependencies for TraitsGUI
    Searching for EnthoughtBase[ui]>
    No local packages or download links found for EnthoughtBase[ui]>
    error: Could not find suitable distribution for Requirement.parse(‘EnthoughtBase[ui]>’)

  2. avatarRobert

    I get this when I do the “easy_install Traits”:

    error: Setup script exited with error: Python was built with Visual Studio 2003;
    extensions must be built with a compiler than can generate compatible binaries.
    Visual Studio 2003 was not found on this system. If you have Cygwin installed,
    you can try compiling with MingW32, by passing “-c mingw32” to

    I have Python 2.5.2 from the Python site.

  3. avatardpeterson

    Tim: Thanks! That is what I get for copying and pasting within WordPress. The links should now all work.

    Robert: Until we get the Windows binaries built and pushed up to PyPi, you’ll need to install either Visual Studio or MingW32 because Traits include some C code as a Python extension that must be built when installing from a source tarball. We anticipate having the Windows binaries up within a day or so.


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