How to interface Ruby with Mercurial (Python)? - python

I'm hoping to integrate Mercurial into my Rails site. I want to run basic commands like status, summary, log, and maybe even clone. I'd like to interface directly with the Mercurial libraries and avoid doing any command line parsing via regex.
Mercurial is written in Python; I am using Ruby. So, I need Mercurial Ruby bindings. It seems, however, that there are none. So, plan B would be to go with something like Ruby/Python (an extension library to embed the Python interpreter in Ruby) or rubypython (a C bridge between Ruby and Python with a Ruby interface).
Do you all see any reason why one of these libraries won't provide me what I am wanting?
Does anyone have any alternative ideas?

I would look at the redmine code, and do whatever they do.

So, I need Mercurial Ruby bindings. It seems, however, that there are none.
You are right. But there is something even better than a Ruby binding to the Python Mercurial implementation: a Ruby (plus little bits of C) Mercurial implementation!

Check out the Mercurial-Ruby gem, released by the team at Beanstalk.
https://github.com/iSabanin/mercurial-ruby

Related

How to integrate a python library into a Ruby on Rails application

I want to know if there is a way to integrate a library written in Python into my Rails application. I have always used gems to implement outside libraries so I have no idea how to do this(yet).
Is it possible to use this Python library?
This is mostly what you want:
Calling Python from Ruby
I've looked into this question before and, excepting the Heroku deploy, the answer was "easily! check this out". (On a fun note, there's a gem to let you embed Perl code in a Ruby file)
However, while I can't seem to find it right now, I remember reading that deploying both to Heroku required a custom buildpac, since one won't normally include the binaries necessary for the other.

Would it be possible to integrate Python or Perl with Ruby?

Would it be possible to integrate Python (and/or Perl) and Ruby? I've looked at http://www.goto.info.waseda.ac.jp/~fukusima/ruby/python/doc/ and http://code.google.com/p/ruby-perl/ , but they both seem rather outdated.
Has someone generated a Ruby interface for Python's C API?
Edit: Python can be integrated with many other languages according to http://wiki.python.org/moin/IntegratingPythonWithOtherLanguages . However, that list doesn't include Ruby.
My school (Georgia Tech), along with Bryn Mawr and Microsoft Research, are doing a project right now called Pyjama. Basically, it uses the Microsoft DLR to allow you to freely mix Python and Ruby. I haven't tried it, but it sounds pretty cool.
Here's an example from the website. You enter the class in "Python mode". Then it gets compiled, and you run the command in "Ruby mode".
class PythonClass:
def hello(self, value):
print "Python says hello to", value
pc = python_class().new
pc.hello "Ruby"
Which produces "Python says hello to Ruby".
Integrating dynamic languages is one of the goals of the Parrot project. It's a virtual machine that dynamic language compilers target. Once compiled to the same virtual machine, you should be able to used the "object" form in any of the languages no matter the object's source.
The issue at the moment, however, is stabilizing the virtual machine and finishing off the mostly done compilers. However, that's been the state for a long time. :)
You can write extensions for Ruby in C.
So, if Python has a C API, you can write a C extension for Ruby which uses this API.
I know nothing about the Python API or how large of a piece you want to integrate with, but if it is not too big, this could (possibly) give you a way to run Python code from Ruby.
For a research project I wanted to use the fabulous matplotlib that's available for Python. I also found that library that you referred to. However, it doesn't look like something popular and well tested. So I decided to write the script that generated graphs using pure Python and called it from Ruby via popen. That worked very well for me.
It might by possible, but not very practical. It would be significantly easier to port whatever modules you need from one to the other than it would be to embed one of the interpreters within the other.
If you absolutely have to use both languages in a project, your best option would probably the combination of Jython and Jruby, or IronPython and IronRuby. I'm not sure if you could get them to talk to each other, but at the very least you could host them on the same virtual machine.
Another strategy, as used by Facebook, is to expose APIs via Thrift. You define lightweight service APIs and the RPCs are inter-process.

How do I set up a Python development environment on Linux?

I'm a .NET developer who knows very little about Python, but want to give it a test drive for a small project I'm working on.
What tools and packages should I install on my machine? I'm looking for a common, somewhat comprehensive, development environment.
I'll likely run Ubuntu 9.10, but I'm flexible. If Windows is a better option, that's fine too.
Edit: To clarify, I'm not looking for the bare minimum to get a Python program to run. I wouldn't expect a newbie .NET dev to use notepad and a compiler. I'd recommend Visual Studio, NUnit, SQL Server, etc.
Your system already has Python on it. Use the text editor or IDE of your choice; I like vim.
I can't tell you what third-party modules you need without knowing what kind of development you will be doing. Use apt as much as you can to get the libraries.
To speak to your edit:
This isn't minimalistic, like handing a .NET newbie notepad and a compiler: a decent text editor and the stdlib are all you really need to start out. You will likely need third-party libraries to develop whatever kind of applications you are writing, but I cannot think of any third-party modules all Python programmers will really need or want.
Unlke the .NET/Windows programming world, there is no one set of dev tools that stands above all others. Different people use different editors a whole lot. In Python, a module namespace is fully within a single file and project organization is based on the filesystem, so people do not lean on their IDEs as hard. Different projects use different version control software, which has been booming with new faces recently. Most of these are better than TFS and all are 1000 times better than SourceSafe.
When I want an interactive session, I use the vanilla Python interpreter. Various more fancy interpreters exist: bpython, ipython, IDLE. bpython is the least fancy of these and is supposed to be good about not doing weird stuff. ipython and IDLE can lead to strange bugs where code that works in them doens't work in normal Python and vice-versa; I've seen this first hand with IDLE.
For some of the tools you asked about and some others
In .NET you would use NUnit. In Python, use the stdlib unittest module. There are various third-party extensions and test runners, but unittest should suit you okay.
If you really want to look into something beyond this, get unittest2, a backport of the 2.7 version of unittest. It has incorporated all the best things from the third-party tools and is really neat.
In .NET you would use SQL Server. In Python, you may use PostgreSQL, MySQL, sqlite, or some other database. Python specifies a unified API for databases and porting from one to another typically goes pretty smoothly. sqlite is in the stdlib.
There are various Object Relational Models to make using databases more abstracted. SQLAlchemy is the most notable of these.
If you are doing network programming, get Twisted.
If you are doing numerical math, get numpy and scipy.
If you are doing web development, choose a framework. There are about 200000: Pylons, zope, Django, CherryPy, werkzeug...I won't bother starting an argument by recommending one. Most of these will happily work with various servers with a quick setting.
If you want to do GUI development, there are quite a few Python bindings. The stdlib ships with Tk bindings I would not bother with. There are wx bindings (wxpython), GTK+ bindings (pygtk), and two sets of Qt bindings. If you want to do native Windows GUI development, get IronPython and do it in .NET. There are win32 bindings, but they'll make you want to pull your hair out trying to use them directly.
In order to reduce the chance of effecting/hosing the system install of python, I typically install virtualenv on the ubuntu python install. I then create a virtualenv in my home directory so that subsequent packages I install via pip or easy_install do not effect the system installation. And I add the bin from that virtualenv to my path via .bashrc
$ sudo apt-get install python-virtualenv
$ virtualenv --no-site-packages ~/local
$ PATH=~/local/bin:$PATH #<----- add this to .bashrc to make it permanent
$ easy_install virtualenv #<--- so that project environments are based off your local environment rather than the system, probably not necessary
Install your favorite editor, I like emacs + rope, but editors are a personal preference and there are plenty of choices.
When I start a new project/idea I create a new virtual environment for that project, so that I don't effect dependencies anywhere else. Since I would hate for some of my projects to break due to an upgrade of a library both that project and the new one depends on.
~/projects $ virtualenv --no-site-packages my_new_project.env
~/projects/my_new_project.env $ source bin/activate
(my_new_project.env)~/projects/my_new_project.env $ easy_install paste ipython #whatever else I think I need
(my_new_project.env)~/projects/my_new_project.env $ emacs ./ & # start hacking
When creating a new package...in order to have something that will be easy_installable/pippable use paster create
(my_new_project.env)~/projects/my_new_project.env$ paster create new_package
(my_new_project.env)~/projects/my_new_project.env/new_package$ python setup.py develop new_package
That's the common stuff as far as I can think of it. Everything else would be editor/version control tool specific
Since I'm accustomed to Eclipse, I find Eclipse + PyDev convenient for Python. For quick computations, Idle is great.
I've used Python on Windows and on Ubuntu, and Linux is much cleaner.
If you launch a terminal and type python you'll get an interpreter, where you can start trying stuff.
Just in case you haven't seen it, check out the book Dive Into Python, is free on-line.
http://www.diveintopython.org/
Follow the examples in the book using the interpreter.
For storing your work you could use any editor; Vim or EMACS could be the most powerful, but also the most difficult to learn at first. If you want a more "traditional" IDE, you could try WingIDE.
http://www.wingware.com/
After you start to get more comfortable with python you should try an enhanced interpreter; try ipython.
http://ipython.scipy.org/moin/
When you start to develop a more serious project you'll need to get additional modules. Here you have two options; 1) Use your distribution tools to install additional modules; or 2) Download the modules you need directly from their sites and install them manually. You'll be responsible to upgrade them of course.
You'll have to decide for yourself which way to go. Personally I prefer to download and install additional modules manually.
Python (duh), setuptools or pip, virtualenv, and an editor. I suggest geany, but that's just me. And of course, any other Python modules you'll need.
Getting to Python from .NET world
Jumping into the Linux world from a .NET / WIndows background can be a bit disconcerting (but I do encourage you to keep trying Linux)
But I would suggest to anyone coming from Windows, to stick with Windows for a little while. goto www.Activestate.com and download their Python package - it includes the full win32com extentions by Mark Hammond and it also includes a complete, fast IDE "pythonwin"
I have done real professional development with just this setup alone on a windows box - one 14MB .msi and off you go !
Now to use Python on the DLR (Dynamic common language runtime) you need to download IronPython. THis is a seperate interpreter, that was also originally written by Mark Hammond at Microsoft and is at ironpython.org.
With this you can run code like (from wikipedia) ::
import clr
clr.AddReference("System.Windows.Forms")
from System.Windows.Forms import MessageBox
MessageBox.Show("Hello World")
Now you can access any .NET code from python.
If you're just starting out with Python, I'd actually argue against bringing in the complexity of virtualenv (which I think can be pretty overwhelming), at least until you've got a firm grasp of Python basics (especially regarding library/dependency management).
If you're using Ubuntu and the Gnome desktop environment, gedit is the default (gui) text editor, and has great support for Python built in. So my recommendation is to start with the pre-installed Python and gedit (which is pretty extensible on its own).
You don't need much. Python comes with "Batteries Included."
Visual Studio == IDLE. You already have it. If you want more IDE-like environment, install Komodo Edit.
NUnit == unittest. You already have it in the standard library.
SQL Server == sqlite. You already have it in the standard library.
Stop wasting time getting everything ready. It's already there in the basic Python installation.
Get to work.
Linux, BTW, is primarily a development environment. It was designed and built by developers for developers. Windows is an end-user environment which has to be supplemented for development.
Linux was originally focused on developers. All the tools you need are either already there or are part of simple yum or RPM installs.
You would probably like to give NetBeans Python IDE a shot. You can choose to use either Windows/Linux.
Database: sqlite (inbuilt). You might want SQLAlchemy though.
GUI: tcl is inbuilt, but wxPython or pyQt are recommended.
IDE: I use idle (inbuilt) on windows, TextMate on Mac, but you might like PyDev. I've also heard good things about ulipad.
Numerics: numpy.
Fast inline code: lots of options. I like boost weave (part of scipy), but you could look into ctypes (to use dlls), Cython, etc.
Web server: too many options. Django (plus Apache) is the biggest.
Unit testing: inbuilt.
Pyparsing, just because.
BeautifulSoup (or another good HTML parser).
hg, git, or some other nice VC.
Trac, or another bug system.
Oh, and StackOverflow if you have any questions.
Pycharm Community is worth to try.

Pure Python in Xcode?

Could anyone tell me how to use pure Python without Cocoa support in Xcode? I can only find the Cocoa-Python template on the Internet.
Thanks in advance.
If you are just trying to write pure Python command line tools, using Xcode is like using a big sledge hammer to hit a tiny nail, in other words, probably not the best tool for the job. There are some old posts out there about how to set up a pure Python Xcode project, like this one, but, in the end, you might be better off using an editor you're already familiar with, like emacs, or, if you don't mind spending a little bit of money, TextMate, all along with a free vcs like mercurial or git. Or take a look in MacPorts for those and other options.
Just about the best IDE for editing and running Python code is actually still emacs. The python-mode for emacs does a wonderful job of maintaining whitespace and, with a bit of configuration, emacs is truly a powerful editor.
Pretty radically different than your typical GUI editor, certainly, and some find it quite distasteful. I've personally used emacs, mostly, for editing Python since 1992 or so.
Google will reveal all, including a native version of Emacs for Mac OS X.
A lot of people like eclipse with PyDev for python, although I don't know how wel it works on OS X with apple's mishandling of java.
Even though I am using BBEdit, I found Wingware Python editor did a good job in exploiting the introspected data of Python modules. Purely designed for Python. Give it a try.
http://www.wingide.com/

Is there a Rake equivalent in Python?

Rake is a software build tool written in Ruby (like Ant or Make), and so all its files are written in this language. Does something like this exist in Python?
Invoke — Fabric without the SSH dependencies.
The Fabric roadmap discusses that Fabric 1.x will be split into three portions:
Invoke — The non-SSH task execution.
Fabric 2.x — The remote execution and deployment library that utilizes Invoke.
Patchwork — The "common deployment/sysadmin operations, built on Fabric."
Invoke is a Python (2.6+ and 3.3+) task execution tool & library, drawing inspiration from various sources to arrive at a powerful & clean feature set.
Below are a few descriptive statements from Invoke's website:
Invoke is a Python (2.6+ and 3.3+) task execution tool & library, drawing inspiration from various sources to arrive at a powerful & clean feature set.
Like Ruby’s Rake tool and Invoke’s own predecessor Fabric 1.x, it provides a clean, high level API for running shell commands and defining/organizing task functions from a tasks.py file.
Paver has a similar set of goals, though I don't really know how it compares.
Shovel seems promising:
Shovel — Rake for Python
https://github.com/seomoz/shovel
Waf is a Python-based framework for configuring, compiling and installing applications. It derives from the concepts of other build tools such as Scons, Autotools, CMake or Ant.
There is also doit - I came across it while looking for these things a while ago, though I didn't get very far with evaluating it.
Although it is more commonly used for deployment, Fabric might be interesting for this use case.
Also check out buildout, which isn't so much a make system for software, as a make system for a deployment.
http://pypi.python.org/pypi/pysqlite/2.5.5
So it's not a direct rake equivalent, but may be a better match for what you want to do, or a really lousy one.
There is Phantom in Boo (which isn't Python, but nearly).
I would check out distutils:
The distutils package provides support
for building and installing additional
modules into a Python installation.
The new modules may be either
100%-pure Python, or may be extension
modules written in C, or may be
collections of Python packages which
include modules coded in both Python
and C.

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