Archive for the ‘planet-mageia-english’ tag
In last weeks I developed some new features to python backend for Cantor. In this post I will write about two of their: the help and the variable management, implemented as panels.
Help Panel on left; Variable Management Panel on right
Help panel shows the help output in a separated panel, facilitating the consult of this information. To use it, simply use help command as in python interactive mode, as in example below:
Below a bigger help output, from a python module:
In previous picture, did you see some change in variable management panel?
Variable Management panel
Variable management panel is a great feature provide by Cantor, but until now just Octave backend had it. This feature show the variables defined in the session, their values, and allow some interesting functions to manipulate these variables.
You can define a lot of variables in python session and these variables will be shown in the panel. See:
In previous picture, I defined a integer variables x and y, a string a, and two modules: numpy and scipy, this last as sc. All this values are shown in panel.
Now I will change some values defined previously and will add some others:
See, now I defined a variable aa by the concatenation of two a‘s; the value of a is now aa; div is the division of y by x. I have a 2-dimensional matrix mtr defined by matrix function from numpy module; a python class HelloWorldClass and a object hello.
I can change the value of some these variable manipulating their values in the panel. For example, I can rewrite the x variable from 35 to 350, clicking in value column and typing 350.
But the more interesting features are provide by the buttons bellow this panel. These buttons load python scripts to run some feature. There are: add variable, load variables from a file, save variables to a file and clear all variables in the session.
Add variable is quite simple: a dialog is open and you type the variable and their value:
Save/Load use shelve module to save and load the variables of the session. But, it is important to say, this feature don’t save all the variables because shelve module have some limitations. For example, I saved this session to a file named “python_session.txt”. The python code loaded is:
After save, I will clear the session. The python code loaded is:
It is working now but I need some more tests, in special the save/load python objects defined by user and modules.
I would like to see some feedback from you. The code is hosted in python-backend branch from Cantor repository, so you can test it.
In previous post, I mentioned about dynamic keywords in python backend. The idea is, after import a python module in Cantor workspace, functions, keywords, variables, and more from this module are load by Cantor and available to syntax highlighting and tab complete.
This feature is implemented for now. You can test it compiling Cantor from python-backend branch.
But, let me show more information about this feature.
There are several ways to import a python module in python console. You have “import modulename”, “import modulename as modulevariable”, “from modulename import *”, “from modulename import function_1, function_2, …”, and more. Each import way causes different consequences to user experience.
The four import ways mentioned in previous paragraph are supported by python backend. I will show these different import ways and how python backend behave for each one.
The more basic import way. After this command, a variable named “modulename” is defined and the functions and more keywords of this module are available to access using “modulename.keyword”.
import modulename as modulevariable
This way the user define a name “modulevariable” to reference “modulename”, and “modulename” is not defined. So, you can access the functions and more from “modulename” using “modulevariable.keyword”.
from modulename import *
This way the user import all functions and keywords from “modulename” but anything variable is defined to access “modulename”. The functions of the module are accessed directly.
from modulename import function_1, function_2, …
The user import only specific functions from a “modulename”, no all functions.
I developed a Cantor plugin to import modules. This plugin open a dialog to user enter a modulename and, after press Ok, Cantor run “import modulename” and keywords are available. The diaglog is accessible by “Packaging” menu, in toolbar.
The backend can identify several errors during import.
Well, the feature is working and it is mature for use, however it don’t support all import ways in python. But, I think these five ways cover the most commons import ways used by most python scientific users.
The important thing is, this feature enable python backend to support the several python modules, and no only scipy, numpy, and matplotlib, as I proposed in begin of this project.
Let me know how you import a module in python. I will develop support to more import ways in future versions of the backend.
For now, wait for more news of this project soon!
Firstly I developed preliminary versions of syntax highlighting and tab complete features. This version use XML file processing to provide a basic set of keywords and built-in functions to these features. To activate tab complete, press Tab button after some letter. You can see some screenshots of these features below (click mouse right-button and enlarge it):
A simple syntax highlighting
More syntax highlighting and tab complete
Next, the preliminary version of the backend developed during LaKademy was build to support python script mode. But it would be more interesting to support python interactive mode in Cantor console. So, to do it, I implemented preprocessing in python command before send it to python interpreter, adding some commands to simulate python interactive mode.
This solution use PyRun_SimpleString from python/C API to process python commands in python script mode. There is other functions from python/C API to process python commands in interactive mode, for example, PyRun_InteractiveOne, but this function requires the python commands in a file to process and the output of commands is a bit of hard to get. So, for now, PyRun_SimpleString + preprocessing commands is working very well.
You can see in screenshots below and above that variable values and operation values are show in Cantor console without use of print command. It is a one of characteristic of python interactive mode:
More examples of syntax highlighting and python interactive mode
Now I am developing a feature to list all functions and keywords from a specific python module imported during the program execution. I am using dir command to do it. This feature will provide these keywords to use in syntax highlighting and tab complete in a dynamic way. Then, python backend will support any python module, and not scipy, numpy, and matplotlib only.
Python backend is available in python-backend branch in Cantor repository. You can test it, but remember this code is not stable and finalized for now.
This year I have a project accepted to Google Summer of Code. This is my second time in the program and I am very happy and grateful for it
This year I come back to Cantor, the KDE mathematical environment for several mathematical softwares like Maxima, Sage, Scilab, etc. In 2011 I developed the Scilab backend during Google Summer of Code. My mentor was Sylvestre Ledru, from Scilab team.
This time my project is conclude the scientific python backend for Cantor. I began the development of this piece of software during LaKademy. The communication between Cantor and python is working properly. The software miss some features of IDE, like tab-complete and syntax highlight. I intent provide support to scipy, numpy and matplotlib too. Alexander Rieder, from KDE, is my supervisor.
There are some ideas about how to implement tab-complete and syntax highlight. It is possible using XML files (like I implemented in Scilab backend) or use the Kdevelop technology. I am researching which I will use.
More updates will come soon! Follow the tag gsoc2013-python-backend this blog!
This is just a manner of speaking. = D
I started contributing to Mageia since the early days of the project, translating the manifesto to Portuguese. Since then I helped on forums, IRC, mailing lists, got mirrors with high performance in Brazil, and did more work in promotion. However, I wanted to provide software for Mageia, because this is a job who not everyone can contribute.
To become a packers I had to participate in a mentoring program where I was guided by my Portuguese friend José Jorge or zezinho. I learned a lot about the art of creating RPM packages. Thanks zezinho!
Well, this is my way to contribute to free software. Thank you, community!