On Mon, Dec 28, 2009 at 03:52, Yitzchak Gale
John Millikin wrote:
It has only a minimal binding to libpython, enough to implement its class instances but not enough for general-purpose use of libpython.
I'm not sure what you mean by that. Using MissingPy, you can instantiate a Python object of any type, marshall data back and forth between Python and Haskell for the basic built-in Python types and any object built out of them, access any Python module, and call any Python function or method. Most people find those capabilities to be quite good for general-purpose use. What do you feel is missing?
http://docs.python.org/3.1/c-api/init.html http://docs.python.org/3.1/c-api/reflection.html Most of http://docs.python.org/3.1/c-api/concrete.html Most of http://docs.python.org/3.1/c-api/abstract.html While it is possible to emulate some C API procedures using Python encoded in Haskell, I find the C API more readable. Compare: --------------------------------------------------------- -- emptySet :: IO Set callArgs (getItem (getAttribute (importModule "types") "__builtins__") "set") [] >>= fmap fromJust cast toList [] >>= iterableToSet --------------------------------------------------------- And of course, it's very difficult to do things like create a new interpreter or modify the "sys" module from within a running interpreter.
I wrote this package so I could benchmark Python modules using Criterion, with an eye towards writing extension modules in Haskell, so it has many more data types and computations available.
Oh, you want to write Python extension modules in Haskell? Right, MissingPy explicitly does not cover calling Haskell from Python.
Eventually -- Python 3 improved the module system enough that it should be possible (compared to 2.x, where C-style static memory was essentially required). I'd like to try (for example) implementing the Python "decimal.Decimal" type in terms of Haskell's Ratio.
For accessing Python from Haskell, though, MissingPy has been around for a long time and works well. There may be quite a lot of code around that uses it. Is your API similar? Is there any specific new capability that you are adding? Do you have some compatibility recommendations?
My API's not similar -- one of my goals was to match the C API as closely as is reasonable, with more type safety. According to the reverse dependency-enabled Hackage[1], as of December 24[2] there are no dependencies on MissingPy. In contrast, there are 27 direct and 17 indirect dependencies on MissingH. [1] http://bifunctor.homelinux.net/~roel/cgi-bin/hackage-scripts/package/Missing... [2] http://bifunctor.homelinux.net/~roel/hackage/packages/archive/recent.html