Hi Pythraners, in order to get a more robust pythran, I have began to had all code snippets from http://rosettacode.org/wiki/Python to the pythran test bed, see pythran/tests/rosetta/*.py All test case that are not dynamically typed and do not use classes or not supported modules should be included in the test bed, using the following conventions: * the first line of the test is the url where it was retreived * each test defines a test function with no args that returns some deterministic values (see existing tests) In case of a pythran error (but can it really happen?), you can add the according bug fix, and do the pull request, or report it as a bug fix using github bug tracker. IRC is fine too. Likewise, some non supported functions may be needed, if it seems relevant to add them, just do it, add unit testing in addition to the rosetta test case and submit the patch! To synchronize, post to this mlist the first letter of the test case your are translating. I'll start with Z (there should be no race condition, as there a re not that many devs here). Have fun! PS: pierick, you can focus on this before forward substitution