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LaKademy<\/a><\/em> is over and I will report about the event in several themed posts. This is about I developed during the Latin American meeting of KDE developers. More posts in LaKademy tag<\/a>.<\/em> In this year I submitted a proposal to Google Summer of Code to develop a Python<\/a> backend for scientific programming in\u00a0Cantor<\/a>. In the last year, I developed a\u00a0Scilab<\/a> backend. Unfortunately my proposal was not accepted.<\/p>\n But that’s okay, life goes on. This does not discourage me to begin the project.<\/p>\n During the LaKademy, I put as a goal to make communication between Cantor and Python. My first idea was to make a fork of\u00a0Sage<\/a> backend, which is also a technology based in Python. But in the evaluation phase of proposal for Google Summer of Code, the Cantor main developer, Alex Rieder, suggested to me take a look in Python\/C API<\/a>.<\/p>\n I began studying this API and other resources on the web (like this one<\/a>, based on Elmer<\/a>). I realized that send Python commands from C\/C++ code would be easy, however, capture the output of the Python interpreter would be the real challenge. All this communication could be simple if Python would use\u00a0standard streams<\/a> by default, which would allow to use kprocess<\/a>. Scilab didn’t support, but I implemented this support and it allowed the use of kprocess approach. However, in Python I could not do that – or would be harder to do it.<\/p>\n After searches in internet and some studies, I implemented a Python class that redirects messages from the Python interpreter, both conventional outputs and error messages, to a variable that can later be retrieved in a string type by Python\/C API. Voil\u00e0<\/em>!<\/p>\n Using this recovered variable, I can say that the core of Python backend for Cantor is working and ready to implement more features. Let see some screenshots:<\/p>\n Computation of a simple counter in Python<\/em><\/p>\n Cantor + Python + matplotlib in a external plot <\/em> From this implemented part, the new features that will be added: append plot figure in Cantor workspace, syntax highlighting, auto-complete pre-defined functions, and more. I intend to support in particular for libraries\u00a0numpy<\/a>, scipy<\/a> and matplotlib<\/a>, which when added to Python make it an interesting tool for scientific programming, like others we have in the free world as\u00a0GNU Octave<\/a>, Scilab, Maxima<\/a>, Sage.<\/p>\n The code is avaiable in python-backend branch<\/a> of Cantor repository<\/a>. But remember: it is a experimental version, and the main fatures will be develop yet. Only communication between C++ <-> Python, the core of application, is working for now.<\/p>\n Watch this blog (or follow python-backend tag<\/a>) for more informations about this project. \ud83d\ude09<\/p>\n
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Python error message in Cantor<\/em><\/p>\n![\"\"](\"http:\/\/blog.filipesaraiva.info\/wp-content\/uploads\/2012\/04\/logo-camisa-01_wee.jpg\"){kind=logo}
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