Revert "Documentation: rewrite Python docs"

3 files changed, 447 insertions, 674 deletions

diff --git a/doc/default.nix b/doc/default.nix
index 203555de131e..196b9e445390 100644
--- a/doc/default.nix
+++ b/doc/default.nix
@@ -45,10 +45,6 @@ stdenv.mkDerivation {
   + toDocbook {
       inputFile = ./introduction.md;
       outputFile = "introduction.xml";
-    }
-  + toDocbook {
-      inputFile = ./languages-frameworks/python.md;
-      outputFile = "./languages-frameworks/python.xml";
       useChapters = true;
     }
   + toDocbook {
@@ -65,8 +61,6 @@ stdenv.mkDerivation {
       outputFile = "languages-frameworks/r.xml";
     }
   + ''
-    cat -n languages-frameworks/python.xml
-
     echo ${nixpkgsVersion} > .version
 
     xmllint --noout --nonet --xinclude --noxincludenode \
diff --git a/doc/languages-frameworks/python.md b/doc/languages-frameworks/python.md
deleted file mode 100644
index d05cabac3ff6..000000000000
--- a/doc/languages-frameworks/python.md
+++ /dev/null
@@ -1,668 +0,0 @@
-# Python
-
-## User Guide
-
-Several versions of Python are available on Nix as well as a high amount of
-packages. The default interpreter is CPython 2.7.
-
-### Using Python
-
-#### Installing Python and packages
-
-It is important to make a distinction between Python packages that are
-used as libraries, and applications that are written in Python.
-
-Applications on Nix are installed typically into your user
-profile imperatively using `nix-env -i`, and on NixOS declaratively by adding the
-package name to `environment.systemPackages` in `/etc/nixos/configuration.nix`.
-Dependencies such as libraries are automatically installed and should not be
-installed explicitly.
-
-The same goes for Python applications and libraries. Python applications can be
-installed in your profile, but Python libraries you would like to use to develop
-cannot. If you do install libraries in your profile, then you will end up with
-import errors.
-
-#### Python environments using `nix-shell`
-
-The recommended method for creating Python environments for development is with
-`nix-shell`. Executing
-
-```sh
-$ nix-shell -p python35Packages.numpy python35Packages.toolz
-```
-
-opens a Nix shell which has available the requested packages and dependencies.
-Now you can launch the Python interpreter (which is itself a dependency)
-
-```sh
-[nix-shell:~] python3
-```
-
-If the packages were not available yet in the Nix store, Nix would download or
-build them automatically. A convenient option with `nix-shell` is the `--run`
-option, with which you can execute a command in the `nix-shell`. Let's say we
-want the above environment and directly run the Python interpreter
-
-```sh
-$ nix-shell -p python35Packages.numpy python35Packages.toolz --run "python3"
-```
-
-This way you can use the `--run` option also to directly run a script
-
-```sh
-$ nix-shell -p python35Packages.numpy python35Packages.toolz --run "python3 myscript.py"
-```
-
-In fact, for this specific use case there is a more convenient method. You can
-add a [shebang](https://en.wikipedia.org/wiki/Shebang_(Unix)) to your script
-specifying which dependencies Nix shell needs. With the following shebang, you
-can use `nix-shell myscript.py` and it will make available all dependencies and
-run the script in the `python3` shell.
-
-```py
-#! /usr/bin/env nix-shell
-#! nix-shell -i python3 -p python3Packages.numpy
-
-import numpy
-
-print(numpy.__version__)
-```
-
-Likely you do not want to type your dependencies each and every time. What you
-can do is write a simple Nix expression which sets up an environment for you,
-requiring you only to type `nix-shell`. Say we want to have Python 3.5, `numpy`
-and `toolz`, like before, in an environment. With a `shell.nix` file
-containing
-
-```nix
-with import <nixpkgs> {};
-
-(pkgs.python35.buildEnv.override  {
-  extraLibs = with pkgs.python35Packages; [ numpy toolz ];
-}).env
-```
-executing `nix-shell` gives you again a Nix shell from which you can run Python.
-
-What's happening here?
-
-1. We begin with importing the Nix Packages collections. `import <nixpkgs>` import the `<nixpkgs>` function, `{}` calls it and the `with` statement brings all attributes of `nixpkgs` in the local scope. Therefore we can now use `pkgs`.
-2. Then we create a Python 3.5 environment with `pkgs.buildEnv`. Because we want to use it with a custom set of Python packages, we override it.
-3. The `extraLibs` argument of the original `buildEnv` function can be used to specify which packages should be included. We want `numpy` and `toolz`. Again, we use the `with` statement to bring a set of attributes into the local scope.
-4. And finally, for in interactive use we return the environment.
-
-### Developing with Python
-
-
-Now that you know how to get a working Python environment on Nix, it is time to go forward and start actually developing with Python.
-We will first have a look at how Python packages are packaged on Nix. Then, we will look how you can use development mode with your code.
-
-#### Python packaging on Nix
-
-On Nix all packages are built by functions. The main function in Nix for building Python packages is [`buildPythonPackage`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/generic/default.nix).
-Let's see how we would build the `toolz` package. According to [`python-packages.nix`](https://raw.githubusercontent.com/NixOS/nixpkgs/master/pkgs/top-level/python-packages.nix) `toolz` is build using
-
-```nix
-toolz = buildPythonPackage rec{
-  name = "toolz-${version}";
-  version = "0.7.4";
-
-  src = pkgs.fetchurl{
-    url = "https://pypi.python.org/packages/source/t/toolz/toolz-${version}.tar.gz";
-    sha256 = "43c2c9e5e7a16b6c88ba3088a9bfc82f7db8e13378be7c78d6c14a5f8ed05afd";
-  };
-
-  meta = {
-    homepage = "http://github.com/pytoolz/toolz/";
-    description = "List processing tools and functional utilities";
-    license = licenses.bsd3;
-    maintainers = with maintainers; [ fridh ];
-  };
-};
-```
-
-What happens here? The function `buildPythonPackage` is called and as argument
-it accepts a set. In this case the set is a recursive set ([`rec`](http://nixos.org/nix/manual/#sec-constructs)).
-One of the arguments is the name of the package, which consists of a basename
-(generally following the name on PyPi) and a version. Another argument, `src`
-specifies the source, which in this case is fetched from an url. `fetchurl` not
-only downloads the target file, but also validates its hash. Furthermore, we
-specify some (optional) [meta information](http://nixos.org/nixpkgs/manual/#chap-meta).
-
-The output of the function is a derivation, which is an attribute with the name
-`toolz` of the set `pythonPackages`. Actually, sets are created for all interpreter versions,
-so `python27Packages`, `python34Packages`, `python35Packages` and `pypyPackages`.
-
-The above example works when you're directly working on
-`pkgs/top-level/python-packages.nix` in the Nixpkgs repository. Often though,
-you will want to test a Nix expression outside of the Nixpkgs tree. If you
-create a `shell.nix` file with the following contents
-
-```nix
-with import <nixpkgs> {};
-
-pkgs.python35Packages.buildPythonPackage rec {
-  name = "toolz-${version}";
-  version = "0.7.4";
-
-  src = pkgs.fetchurl{
-    url = "https://pypi.python.org/packages/source/t/toolz/toolz-${version}.tar.gz";
-    sha256 = "43c2c9e5e7a16b6c88ba3088a9bfc82f7db8e13378be7c78d6c14a5f8ed05afd";
-  };
-
-  meta = {
-    homepage = "http://github.com/pytoolz/toolz/";
-    description = "List processing tools and functional utilities";
-    license = licenses.bsd3;
-    maintainers = with maintainers; [ fridh ];
-  };
-}
-```
-
-and then execute `nix-shell` will result in an environment in which you can use
-Python 3.5 and the `toolz` package. As you can see we had to explicitly mention
-for which Python version we want to build a package.
-
-The above example considered only a single package. Generally you will want to use multiple packages.
-If we create a `shell.nix` file with the following contents
-
-```nix
-with import <nixpkgs> {};
-
-( let
-    toolz = pkgs.python35Packages.buildPythonPackage rec {
-      name = "toolz-${version}";
-      version = "0.7.4";
-
-      src = pkgs.fetchurl{
-        url = "https://pypi.python.org/packages/source/t/toolz/toolz-${version}.tar.gz";
-        sha256 = "43c2c9e5e7a16b6c88ba3088a9bfc82f7db8e13378be7c78d6c14a5f8ed05afd";
-      };
-
-      meta = {
-        homepage = "http://github.com/pytoolz/toolz/";
-        description = "List processing tools and functional utilities";
-        license = licenses.bsd3;
-        maintainers = with maintainers; [ fridh ];
-      };
-    };
-
-  in pkgs.python35.buildEnv.override rec {
-
-    extraLibs = [ pkgs.python35Packages.numpy toolz ];
-}
-).env
-```
-
-and again execute `nix-shell`, then we get a Python 3.5 environment with our
-locally defined package as well as `numpy` which is build according to the
-definition in Nixpkgs. What did we do here? Well, we took the Nix expression
-that we used earlier to build a Python environment, and said that we wanted to
-include our own version of `toolz`. To introduce our own package in the scope of
-`buildEnv.override` we used a
-[`let`](http://nixos.org/nix/manual/#sec-constructs) expression.
-
-### Handling dependencies
-
-Our example, `toolz`, doesn't have any dependencies on other Python
-packages or system libraries. According to the manual,  `buildPythonPackage`
-uses the arguments `buildInputs` and `propagatedBuildInputs` to specify dependencies. If something is
-exclusively a build-time dependency, then the dependency should be included as a
-`buildInput`, but if it is (also) a runtime dependency, then it should be added
-to `propagatedBuildInputs`. Test dependencies are considered build-time dependencies.
-
-The following example shows which arguments are given to `buildPythonPackage` in
-order to build [`datashape`](https://github.com/blaze/datashape).
-
-```nix
-datashape = buildPythonPackage rec {
-  name = "datashape-${version}";
-  version = "0.4.7";
-
-  src = pkgs.fetchurl {
-    url = "https://pypi.python.org/packages/source/D/DataShape/${name}.tar.gz";
-    sha256 = "14b2ef766d4c9652ab813182e866f493475e65e558bed0822e38bf07bba1a278";
-  };
-
-  buildInputs = with self; [ pytest ];
-  propagatedBuildInputs = with self; [ numpy multipledispatch dateutil ];
-
-  meta = {
-    homepage = https://github.com/ContinuumIO/datashape;
-    description = "A data description language";
-    license = licenses.bsd2;
-    maintainers = with maintainers; [ fridh ];
-  };
-};
-```
-
-We can see several runtime dependencies, `numpy`, `multipledispatch`, and
-`dateutil`. Furthermore, we have one `buildInput`, i.e. `pytest`. `pytest` is a
-test runner and is only used during the `checkPhase` and is therefore not added
-to `propagatedBuildInputs`.
-
-In the previous case we had only dependencies on other Python packages to consider.
-Occasionally you have also system libraries to consider. E.g., `lxml` provides
-Python bindings to `libxml2` and `libxslt`. These libraries are only required
-when building the bindings and are therefore added as `buildInputs`.
-
-```nix
-lxml = buildPythonPackage rec {
-  name = "lxml-3.4.4";
-
-  src = pkgs.fetchurl {
-    url = "http://pypi.python.org/packages/source/l/lxml/${name}.tar.gz";
-    sha256 = "16a0fa97hym9ysdk3rmqz32xdjqmy4w34ld3rm3jf5viqjx65lxk";
-  };
-
-  buildInputs = with self; [ pkgs.libxml2 pkgs.libxslt ];
-
-  meta = {
-    description = "Pythonic binding for the libxml2 and libxslt libraries";
-    homepage = http://lxml.de;
-    license = licenses.bsd3;
-    maintainers = with maintainers; [ sjourdois ];
-  };
-};
-```
-
-In this example `lxml` and Nix are able to work out exactly where the relevant
-files of the dependencies are. This is not always the case.
-
-The example below shows bindings to The Fastest Fourier Transform in the West, commonly known as
-FFTW. On Nix we have separate packages of FFTW for the different types of floats
-(`"single"`, `"double"`, `"long-double"`). The bindings need all three types,
-and therefore we add all three as `buildInputs`. The bindings don't expect to
-find each of them in a different folder, and therefore we have to set `LDFLAGS`
-and `CFLAGS`.
-
-```nix
-pyfftw = buildPythonPackage rec {
-  name = "pyfftw-${version}";
-  version = "0.9.2";
-
-  src = pkgs.fetchurl {
-    url = "https://pypi.python.org/packages/source/p/pyFFTW/pyFFTW-${version}.tar.gz";
-    sha256 = "f6bbb6afa93085409ab24885a1a3cdb8909f095a142f4d49e346f2bd1b789074";
-  };
-
-  buildInputs = [ pkgs.fftw pkgs.fftwFloat pkgs.fftwLongDouble];
-
-  propagatedBuildInputs = with self; [ numpy scipy ];
-
-  # Tests cannot import pyfftw. pyfftw works fine though.
-  doCheck = false;
-
-  LDFLAGS="-L${pkgs.fftw}/lib -L${pkgs.fftwFloat}/lib -L${pkgs.fftwLongDouble}/lib"
-  CFLAGS="-I${pkgs.fftw}/include -I${pkgs.fftwFloat}/include -I${pkgs.fftwLongDouble}/include"
-  '';
-
-  meta = {
-    description = "A pythonic wrapper around FFTW, the FFT library, presenting a unified interface for all the supported transforms";
-    homepage = http://hgomersall.github.com/pyFFTW/;
-    license = with licenses; [ bsd2 bsd3 ];
-    maintainer = with maintainers; [ fridh ];
-  };
-};
-```
-Note also the line `doCheck = false;`, we explicitly disabled running the test-suite.
-
-
-#### Develop local package
-
-As a Python developer you're likely aware of [development mode](http://pythonhosted.org/setuptools/setuptools.html#development-mode) (`python setup.py develop`);
-instead of installing the package this command creates a special link to the project code.
-That way, you can run updated code without having to reinstall after each and every change you make.
-Development mode is also available on Nix as [explained](http://nixos.org/nixpkgs/manual/#ssec-python-development) in the Nixpkgs manual.
-Let's see how you can use it.
-
-In the previous Nix expression the source was fetched from an url. We can also refer to a local source instead using
-
-```nix
-src = ./path/to/source/tree;
-```
-
-If we create a `shell.nix` file which calls `buildPythonPackage`, and if `src`
-is a local source, and if the local source has a `setup.py`, then development
-mode is activated.
-
-In the following example we create a simple environment that
-has a Python 3.5 version of our package in it, as well as its dependencies and
-other packages we like to have in the environment, all specified with `propagatedBuildInputs`.
-Indeed, we can just add any package we like to have in our environment to `propagatedBuildInputs`.
-
-```nix
-with import <nixpkgs>;
-with pkgs.python35Packages;
-
-buildPythonPackage rec {
-  name = "mypackage";
-  src = ./path/to/package/source;
-  propagatedBuildInputs = [ pytest numpy pkgs.libsndfile ];
-};
-```
-
-It is important to note that due to how development mode is implemented on Nix it is not possible to have multiple packages simultaneously in development mode.
-
-
-### Organising your packages
-
-So far we discussed how you can use Python on Nix, and how you can develop with
-it. We've looked at how you write expressions to package Python packages, and we
-looked at how you can create environments in which specified packages are
-available.
-
-At some point you'll likely have multiple packages which you would
-like to be able to use in different projects. In order to minimise unnecessary
-duplication we now look at how you can maintain yourself a repository with your
-own packages. The important functions here are `import` and `callPackage`.
-
-### Including a derivation using `callPackage`
-
-Earlier we created a Python environment using `buildEnv`, and included the
-`toolz` package via a `let` expression.
-Let's split the package definition from the environment definition.
-
-We first create a function that builds `toolz` in `~/path/to/toolz/release.nix`
-
-```nix
-{ pkgs, buildPythonPackage }:
-
-buildPythonPackage rec {
-  name = "toolz-${version}";
-  version = "0.7.4";
-
-  src = pkgs.fetchurl{
-    url = "https://pypi.python.org/packages/source/t/toolz/toolz-${version}.tar.gz";
-    sha256 = "43c2c9e5e7a16b6c88ba3088a9bfc82f7db8e13378be7c78d6c14a5f8ed05afd";
-  };
-
-  meta = {
-    homepage = "http://github.com/pytoolz/toolz/";
-    description = "List processing tools and functional utilities";
-    license = licenses.bsd3;
-    maintainers = with maintainers; [ fridh ];
-  };
-};
-```
-
-It takes two arguments, `pkgs` and `buildPythonPackage`.
-We now call this function using `callPackage` in the definition of our environment
-
-```nix
-with import <nixpkgs> {};
-
-( let
-    toolz = pkgs.callPackage ~/path/to/toolz/release.nix { pkgs=pkgs; buildPythonPackage=pkgs.python35Packages.buildPythonPackage; };
-  in pkgs.python35.buildEnv.override rec {
-    extraLibs = [ pkgs.python35Packages.numpy  toolz ];
-}
-).env
-```
-
-Important to remember is that the Python version for which the package is made
-depends on the `python` derivation that is passed to `buildPythonPackage`. Nix
-tries to automatically pass arguments when possible, which is why generally you
-don't explicitly define which `python` derivation should be used. In the above
-example we use `buildPythonPackage` that is part of the set `python35Packages`,
-and in this case the `python35` interpreter is automatically used.
-
-
-
-## Reference
-
-### Interpreters
-
-Versions 2.6, 2.7, 3.3, 3.4 and 3.5 of the CPython interpreter are available on
-Nix and are available as `python26`, `python27`, `python33`, `python34` and
-`python35`. The PyPy interpreter is also available as `pypy`. Currently, the
-aliases `python` and `python3` correspond to respectively `python27` and
-`python35`. The Nix expressions for the interpreters can be found in
-`pkgs/development/interpreters/python`.
-
-
-#### Missing modules standard library
-
-The interpreters `python26` and `python27` do not include modules that
-require external dependencies. This is done in order to reduce the closure size.
-The following modules need to be added as `buildInput` explicitly:
-
-* `python.modules.bsddb`
-* `python.modules.curses`
-* `python.modules.curses_panel`
-* `python.modules.crypt`
-* `python.modules.gdbm`
-* `python.modules.sqlite3`
-* `python.modules.tkinter`
-* `python.modules.readline`
-
-For convenience `python27Full` and `python26Full` are provided with all
-modules included.
-
-All packages depending on any Python interpreter get appended
-`out/{python.sitePackages}` to `$PYTHONPATH` if such directory
-exists.
-
-#### Attributes on interpreters packages
-
-Each interpreter has the following attributes:
-
-- `libPrefix`. Name of the folder in `${python}/lib/` for corresponding interpreter.
-- `interpreter`. Alias for `${python}/bin/${executable}`.
-- `buildEnv`. Function to build python interpreter environments with extra packages bundled together. See section *python.buildEnv function* for usage and documentation.
-- `sitePackages`. Alias for `lib/${libPrefix}/site-packages`.
-- `executable`. Name of the interpreter executable, ie `python3.4`.
-
-### Building packages and applications
-
-Python packages (libraries) and applications that use `setuptools` or
-`distutils` are typically built with respectively the `buildPythonPackage` and
-`buildPythonApplication` functions.
-
-All Python packages reside in `pkgs/top-level/python-packages.nix` and all
-applications elsewhere. Some packages are also defined in
-`pkgs/development/python-modules`. It is important that these packages are
-called in `pkgs/top-level/python-packages.nix` and not elsewhere, to guarantee
-the right version of the package is built.
-
-Based on the packages defined in `pkgs/top-level/python-packages.nix` an
-attribute set is created for each available Python interpreter. The available
-sets are
-
-* `pkgs.python26Packages`
-* `pkgs.python27Packages`
-* `pkgs.python33Packages`
-* `pkgs.python34Packages`
-* `pkgs.python35Packages`
-* `pkgs.pypyPackages`
-
-and the aliases
-
-* `pkgs.pythonPackages` pointing to `pkgs.python27Packages`
-* `pkgs.python3Packages` pointing to `pkgs.python35Packages`
-
-#### `buildPythonPackage` function
-
-The `buildPythonPackage` function is implemented in
-`pkgs/development/python-modules/generic/default.nix`
-
-and can be used as:
-
-    twisted = buildPythonPackage {
-      name = "twisted-8.1.0";
-
-      src = pkgs.fetchurl {
-        url = http://tmrc.mit.edu/mirror/twisted/Twisted/8.1/Twisted-8.1.0.tar.bz2;
-        sha256 = "0q25zbr4xzknaghha72mq57kh53qw1bf8csgp63pm9sfi72qhirl";
-      };
-
-      propagatedBuildInputs = [ self.ZopeInterface ];
-
-      meta = {
-        homepage = http://twistedmatrix.com/;
-        description = "Twisted, an event-driven networking engine written in Python";
-        license = stdenv.lib.licenses.mit; };
-      };
-
-The `buildPythonPackage` mainly does four things:
-
-* In the `buildPhase`, it calls `${python.interpreter} setup.py bdist_wheel` to build a wheel binary zipfile.
-* In the `installPhase`, it installs the wheel file using `pip install *.whl`.
-* In the `postFixup` phase, the `wrapPythonPrograms` bash function is called to wrap all programs in the `$out/bin/*` directory to include `$PYTHONPATH` and `$PATH` environment variables.
-* In the `installCheck` phase, `${python.interpreter} setup.py test` is ran.
-
-As in Perl, dependencies on other Python packages can be specified in the
-`buildInputs` and `propagatedBuildInputs` attributes.  If something is
-exclusively a build-time dependency, use `buildInputs`; if it’s (also) a runtime
-dependency, use `propagatedBuildInputs`.
-
-By default tests are run because `doCheck = true`. Test dependencies, like
-e.g. the test runner, should be added to `buildInputs`.
-
-By default `meta.platforms` is set to the same value
-as the interpreter unless overriden otherwise.
-
-##### `buildPythonPackage` parameters
-
-All parameters from `mkDerivation` function are still supported.
-
-* `namePrefix`: Prepended text to `${name}` parameter. Defaults to `"python3.3-"` for Python 3.3, etc. Set it to `""` if you're packaging an application or a command line tool.
-* `disabled`: If `true`, package is not build for particular python interpreter version. Grep around `pkgs/top-level/python-packages.nix` for examples.
-* `setupPyBuildFlags`: List of flags passed to `setup.py build_ext` command.
-* `pythonPath`: List of packages to be added into `$PYTHONPATH`. Packages in `pythonPath` are not propagated (contrary to `propagatedBuildInputs`).
-* `preShellHook`: Hook to execute commands before `shellHook`.
-* `postShellHook`: Hook to execute commands after `shellHook`.
-* `makeWrapperArgs`: A list of strings. Arguments to be passed to `makeWrapper`, which wraps generated binaries. By default, the arguments to `makeWrapper` set `PATH` and `PYTHONPATH` environment variables before calling the binary. Additional arguments here can allow a developer to set environment variables which will be available when the binary is run. For example, `makeWrapperArgs = ["--set FOO BAR" "--set BAZ QUX"]`.
-* `installFlags`: A list of strings. Arguments to be passed to `pip install`. To pass options to `python setup.py install`, use `--install-option`. E.g., `installFlags=["--install-option='--cpp_implementation'"].
-
-#### `buildPythonApplication` function
-
-The `buildPythonApplication` function is practically the same as `buildPythonPackage`.
-The difference is that `buildPythonPackage` by default prefixes the names of the packages with the version of the interpreter.
-Because with an application we're not interested in multiple version the prefix is dropped.
-
-#### python.buildEnv function
-
-Python environments can be created using the low-level `pkgs.buildEnv` function.
-This example shows how to create an environment that has the Pyramid Web Framework.
-Saving the following as `default.nix`
-
-    with import {};
-
-    python.buildEnv.override {
-      extraLibs = [ pkgs.pythonPackages.pyramid ];
-      ignoreCollisions = true;
-    }
-
-and running `nix-build` will create
-
-    /nix/store/cf1xhjwzmdki7fasgr4kz6di72ykicl5-python-2.7.8-env
-
-with wrapped binaries in `bin/`.
-
-You can also use the `env` attribute to create local environments with needed
-packages installed. This is somewhat comparable to `virtualenv`. For example,
-running `nix-shell` with the following `shell.nix`
-
-    with import {};
-
-    (python3.buildEnv.override {
-      extraLibs = with python3Packages; [ numpy requests ];
-    }).env
-
-will drop you into a shell where Python will have the
-specified packages in its path.
-
-
-##### `python.buildEnv` arguments
-
-* `extraLibs`: List of packages installed inside the environment.
-* `postBuild`: Shell command executed after the build of environment.
-* `ignoreCollisions`: Ignore file collisions inside the environment (default is `false`).
-
-### Development mode
-
-Development or editable mode is supported. To develop Python packages
-`buildPythonPackage` has additional logic inside `shellPhase` to run `pip
-install -e . --prefix $TMPDIR/`for the package.
-
-Warning: `shellPhase` is executed only if `setup.py` exists.
-
-Given a `default.nix`:
-
-    with import {};
-
-    buildPythonPackage { name = "myproject";
-
-    buildInputs = with pkgs.pythonPackages; [ pyramid ];
-
-    src = ./.; }
-
-Running `nix-shell` with no arguments should give you
-the environment in which the package would be build with
-`nix-build`.
-
-Shortcut to setup environments with C headers/libraries and python packages:
-
-    $ nix-shell -p pythonPackages.pyramid zlib libjpeg git
-
-Note: There is a boolean value `lib.inNixShell` set to `true` if nix-shell is invoked.
-
-### Tools
-
-Packages inside nixpkgs are written by hand. However many tools exist in
-community to help save time. No tool is preferred at the moment.
-
-- [python2nix](https://github.com/proger/python2nix) by Vladimir Kirillov
-- [pypi2nix](https://github.com/garbas/pypi2nix) by Rok Garbas
-- [pypi2nix](https://github.com/offlinehacker/pypi2nix) by Jaka Hudoklin
-
-## FAQ
-
-### How to solve circular dependencies?
-
-Consider the packages `A` and `B` that depend on each other. When packaging `B`,
-a solution is to override package `A` not to depend on `B` as an input. The same
-should also be done when packaging `A`.
-
-### `install_data` / `data_files` problems
-
-If you get the following error:
-
-    could not create '/nix/store/6l1bvljpy8gazlsw2aw9skwwp4pmvyxw-python-2.7.8/etc':
-    Permission denied
-
-This is a [known bug](https://bitbucket.org/pypa/setuptools/issue/130/install_data-doesnt-respect-prefix) in setuptools.
-Setuptools `install_data` does not respect `--prefix`. An example of such package using the feature is `pkgs/tools/X11/xpra/default.nix`.
-As workaround install it as an extra `preInstall` step:
-
-    ${python.interpreter} setup.py install_data --install-dir=$out --root=$out
-    sed -i '/ = data\_files/d' setup.py
-
-
-###  Rationale of non-existent global site-packages
-
-On most operating systems a global `site-packages` is maintained. This however
-becomes problematic if you want to run multiple Python versions or have multiple
-versions of certain libraries for your projects. Generally, you would solve such
-issues by creating virtual environments using `virtualenv`.
-
-On Nix each package has an isolated dependency tree which, in the case of
-Python, guarantees the right versions of the interpreter and libraries or
-packages are available. There is therefore no need to maintain a global `site-packages`.
-
-If you want to create a Python environment for development, then the recommended
-method is to use `nix-shell`, either with or without the `python.buildEnv`
-function.
-
-
-## Contributing
-
-### Contributing guidelines
-
-Following rules are desired to be respected:
-
-* Make sure package builds for all python interpreters. Use `disabled` argument to `buildPythonPackage` to set unsupported interpreters.
-* If tests need to be disabled for a package, make sure you leave a comment about reasoning.
-* Packages in `pkgs/top-level/python-packages.nix` are sorted quasi-alphabetically to avoid merge conflicts.
-* Python libraries are supposed to be in `python-packages.nix` and packaged with `buildPythonPackage`. Python applications live outside of `python-packages.nix` and are packaged with `buildPythonApplication`.
diff --git a/doc/languages-frameworks/python.xml b/doc/languages-frameworks/python.xml
new file mode 100644
index 000000000000..57aceeb48685
--- /dev/null
+++ b/doc/languages-frameworks/python.xml
@@ -0,0 +1,447 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-python">
+
+<title>Python</title>
+
+<para>
+  Currently supported interpreters are <varname>python26</varname>, <varname>python27</varname>,
+  <varname>python33</varname>, <varname>python34</varname>, <varname>python35</varname>
+  and <varname>pypy</varname>.
+</para>
+
+<para>
+  <varname>python</varname> is an alias to <varname>python27</varname> and <varname>python3</varname> is an alias to <varname>python34</varname>.
+</para>
+
+<para>
+  <varname>python26</varname> and <varname>python27</varname> do not include modules that require
+  external dependencies (to reduce dependency bloat). Following modules need to be added as
+  <varname>buildInput</varname> explicitly:
+</para>
+
+<itemizedlist>
+  <listitem><para><varname>python.modules.bsddb</varname></para></listitem>
+  <listitem><para><varname>python.modules.curses</varname></para></listitem>
+  <listitem><para><varname>python.modules.curses_panel</varname></para></listitem>
+  <listitem><para><varname>python.modules.crypt</varname></para></listitem>
+  <listitem><para><varname>python.modules.gdbm</varname></para></listitem>
+  <listitem><para><varname>python.modules.sqlite3</varname></para></listitem>
+  <listitem><para><varname>python.modules.tkinter</varname></para></listitem>
+  <listitem><para><varname>python.modules.readline</varname></para></listitem>
+</itemizedlist>
+
+<para>For convenience <varname>python27Full</varname> and <varname>python26Full</varname>
+are provided with all modules included.</para>
+
+<para>
+  Python packages that
+  use <link xlink:href="http://pypi.python.org/pypi/setuptools/"><literal>setuptools</literal></link> or <literal>distutils</literal>,
+  can be built using the <varname>buildPythonPackage</varname> function as documented below.
+</para>
+
+<para>
+ All packages depending on any Python interpreter get appended <varname>$out/${python.sitePackages}</varname>
+ to <literal>$PYTHONPATH</literal> if such directory exists.
+</para>
+
+<variablelist>
+  <title>
+     Useful attributes on interpreters packages:
+  </title>
+
+  <varlistentry>
+    <term><varname>libPrefix</varname></term>
+    <listitem><para>
+        Name of the folder in <literal>${python}/lib/</literal> for corresponding interpreter.
+    </para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><varname>interpreter</varname></term>
+    <listitem><para>
+        Alias for <literal>${python}/bin/${executable}.</literal>
+    </para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><varname>buildEnv</varname></term>
+    <listitem><para>
+        Function to build python interpreter environments with extra packages bundled together.
+        See <xref linkend="ssec-python-build-env" /> for usage and documentation.
+    </para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><varname>sitePackages</varname></term>
+    <listitem><para>
+      Alias for <literal>lib/${libPrefix}/site-packages</literal>.
+    </para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><varname>executable</varname></term>
+    <listitem><para>
+      Name of the interpreter executable, ie <literal>python3.4</literal>.
+    </para></listitem>
+  </varlistentry>
+
+</variablelist>
+<section xml:id="ssec-build-python-package"><title><varname>buildPythonPackage</varname> function</title>
+
+  <para>
+  The function is implemented in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/generic/default.nix">
+  <filename>pkgs/development/python-modules/generic/default.nix</filename></link>.
+  Example usage:
+
+<programlisting language="nix">
+twisted = buildPythonPackage {
+  name = "twisted-8.1.0";
+
+  src = pkgs.fetchurl {
+    url = http://tmrc.mit.edu/mirror/twisted/Twisted/8.1/Twisted-8.1.0.tar.bz2;
+    sha256 = "0q25zbr4xzknaghha72mq57kh53qw1bf8csgp63pm9sfi72qhirl";
+  };
+
+  propagatedBuildInputs = [ self.ZopeInterface ];
+
+  meta = {
+    homepage = http://twistedmatrix.com/;
+    description = "Twisted, an event-driven networking engine written in Python";
+    license = stdenv.lib.licenses.mit;
+  };
+};
+</programlisting>
+
+  Most of Python packages that use <varname>buildPythonPackage</varname> are defined
+  in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/python-packages.nix"><filename>pkgs/top-level/python-packages.nix</filename></link>
+  and generated for each python interpreter separately into attribute sets <varname>python26Packages</varname>,
+  <varname>python27Packages</varname>, <varname>python35Packages</varname>, <varname>python33Packages</varname>,
+  <varname>python34Packages</varname> and <varname>pypyPackages</varname>.
+  </para>
+
+  <para>
+    <function>buildPythonPackage</function> mainly does four things:
+
+    <orderedlist>
+      <listitem><para>
+        In the <varname>buildPhase</varname>, it calls
+        <literal>${python.interpreter} setup.py bdist_wheel</literal> to build a wheel binary zipfile.
+      </para></listitem>
+
+      <listitem><para>
+        In the <varname>installPhase</varname>, it installs the wheel file using
+        <literal>pip install *.whl</literal>.
+      </para></listitem>
+
+      <listitem><para>
+        In the <varname>postFixup</varname> phase, <literal>wrapPythonPrograms</literal>
+        bash function is called to wrap all programs in <filename>$out/bin/*</filename>
+        directory to include <literal>$PYTHONPATH</literal> and <literal>$PATH</literal>
+        environment variables.
+      </para></listitem>
+
+      <listitem><para>
+        In the <varname>installCheck</varname> phase, <literal>${python.interpreter} setup.py test</literal>
+        is ran.
+      </para></listitem>
+    </orderedlist>
+  </para>
+
+  <para>By default <varname>doCheck = true</varname> is set</para>
+
+  <para>
+    As in Perl, dependencies on other Python packages can be specified in the
+    <varname>buildInputs</varname> and
+    <varname>propagatedBuildInputs</varname> attributes.  If something is
+    exclusively a build-time dependency, use
+    <varname>buildInputs</varname>; if it’s (also) a runtime dependency,
+    use <varname>propagatedBuildInputs</varname>.
+  </para>
+
+  <para>
+    By default <varname>meta.platforms</varname> is set to the same value
+    as the interpreter unless overriden oth