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doc/python: update python version references

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doc/languages-frameworks/python.section.md
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@ -8,9 +8,9 @@
Several versions of the Python interpreter are available on Nix, as well as a Several versions of the Python interpreter are available on Nix, as well as a
high amount of packages. The attribute `python3` refers to the default high amount of packages. The attribute `python3` refers to the default
interpreter, which is currently CPython 3.9. The attribute `python` refers to interpreter, which is currently CPython 3.10. The attribute `python` refers to
CPython 2.7 for backwards-compatibility. It is also possible to refer to CPython 2.7 for backwards-compatibility. It is also possible to refer to
specific versions, e.g. `python38` refers to CPython 3.8, and `pypy` refers to specific versions, e.g. `python39` refers to CPython 3.9, and `pypy` refers to
the default PyPy interpreter. the default PyPy interpreter.
Python is used a lot, and in different ways. This affects also how it is Python is used a lot, and in different ways. This affects also how it is
@ -26,10 +26,10 @@ however, are in separate sets, with one set per interpreter version.
The interpreters have several common attributes. One of these attributes is The interpreters have several common attributes. One of these attributes is
`pkgs`, which is a package set of Python libraries for this specific `pkgs`, which is a package set of Python libraries for this specific
interpreter. E.g., the `toolz` package corresponding to the default interpreter interpreter. E.g., the `toolz` package corresponding to the default interpreter
is `python.pkgs.toolz`, and the CPython 3.8 version is `python38.pkgs.toolz`. is `python.pkgs.toolz`, and the CPython 3.9 version is `python39.pkgs.toolz`.
The main package set contains aliases to these package sets, e.g. The main package set contains aliases to these package sets, e.g.
`pythonPackages` refers to `python.pkgs` and `python38Packages` to `pythonPackages` refers to `python.pkgs` and `python39Packages` to
`python38.pkgs`. `python39.pkgs`.
#### Installing Python and packages {#installing-python-and-packages} #### Installing Python and packages {#installing-python-and-packages}
@ -54,7 +54,7 @@ with `python.buildEnv` or `python.withPackages` where the interpreter and other
executables are wrapped to be able to find each other and all of the modules. executables are wrapped to be able to find each other and all of the modules.
In the following examples we will start by creating a simple, ad-hoc environment In the following examples we will start by creating a simple, ad-hoc environment
with a nix-shell that has `numpy` and `toolz` in Python 3.8; then we will create with a nix-shell that has `numpy` and `toolz` in Python 3.9; then we will create
a re-usable environment in a single-file Python script; then we will create a a re-usable environment in a single-file Python script; then we will create a
full Python environment for development with this same environment. full Python environment for development with this same environment.
@ -70,10 +70,10 @@ temporary shell session with a Python and a *precise* list of packages (plus
their runtime dependencies), with no other Python packages in the Python their runtime dependencies), with no other Python packages in the Python
interpreter's scope. interpreter's scope.
To create a Python 3.8 session with `numpy` and `toolz` available, run: To create a Python 3.9 session with `numpy` and `toolz` available, run:
```sh ```sh
$ nix-shell -p 'python38.withPackages(ps: with ps; [ numpy toolz ])' $ nix-shell -p 'python39.withPackages(ps: with ps; [ numpy toolz ])'
``` ```
By default `nix-shell` will start a `bash` session with this interpreter in our By default `nix-shell` will start a `bash` session with this interpreter in our
@ -81,8 +81,8 @@ By default `nix-shell` will start a `bash` session with this interpreter in our
```Python console ```Python console
[nix-shell:~/src/nixpkgs]$ python3 [nix-shell:~/src/nixpkgs]$ python3
Python 3.8.1 (default, Dec 18 2019, 19:06:26) Python 3.9.12 (main, Mar 23 2022, 21:36:19)
[GCC 9.2.0] on linux [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information. Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy; import toolz >>> import numpy; import toolz
``` ```
@ -102,13 +102,16 @@ will still get 1 wrapped Python interpreter. We can start the interpreter
directly like so: directly like so:
```sh ```sh
$ nix-shell -p 'python38.withPackages(ps: with ps; [ numpy toolz requests ])' --run python3 $ nix-shell -p "python39.withPackages (ps: with ps; [ numpy toolz requests ])" --run python3
these derivations will be built: this derivation will be built:
/nix/store/xbdsrqrsfa1yva5s7pzsra8k08gxlbz1-python3-3.8.1-env.drv /nix/store/mpn7k6bkjl41fm51342rafaqfsl10qs4-python3-3.9.12-env.drv
building '/nix/store/xbdsrqrsfa1yva5s7pzsra8k08gxlbz1-python3-3.8.1-env.drv'... this path will be fetched (0.09 MiB download, 0.41 MiB unpacked):
created 277 symlinks in user environment /nix/store/5gaiacnzi096b6prc6aa1pwrhncmhc8b-python3.9-toolz-0.11.2
Python 3.8.1 (default, Dec 18 2019, 19:06:26) copying path '/nix/store/5gaiacnzi096b6prc6aa1pwrhncmhc8b-python3.9-toolz-0.11.2' from 'https://cache.nixos.org'...
[GCC 9.2.0] on linux building '/nix/store/mpn7k6bkjl41fm51342rafaqfsl10qs4-python3-3.9.12-env.drv'...
created 279 symlinks in user environment
Python 3.9.12 (main, Mar 23 2022, 21:36:19)
[GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information. Type "help", "copyright", "credits" or "license" for more information.
>>> import requests >>> import requests
>>> >>>
@ -147,7 +150,7 @@ Executing this script requires a `python3` that has `numpy`. Using what we learn
in the previous section, we could startup a shell and just run it like so: in the previous section, we could startup a shell and just run it like so:
```ShellSession ```ShellSession
$ nix-shell -p 'python38.withPackages(ps: with ps; [ numpy ])' --run 'python3 foo.py' $ nix-shell -p 'python39.withPackages(ps: with ps; [ numpy ])' --run 'python3 foo.py'
The dot product of [1 2] and [3 4] is: 11 The dot product of [1 2] and [3 4] is: 11
``` ```
@ -210,12 +213,12 @@ create a single script with Python dependencies, but in the course of normal
development we're usually working in an entire package repository. development we're usually working in an entire package repository.
As explained in the Nix manual, `nix-shell` can also load an expression from a As explained in the Nix manual, `nix-shell` can also load an expression from a
`.nix` file. Say we want to have Python 3.8, `numpy` and `toolz`, like before, `.nix` file. Say we want to have Python 3.9, `numpy` and `toolz`, like before,
in an environment. We can add a `shell.nix` file describing our dependencies: in an environment. We can add a `shell.nix` file describing our dependencies:
```nix ```nix
with import <nixpkgs> {}; with import <nixpkgs> {};
(python38.withPackages (ps: [ps.numpy ps.toolz])).env (python39.withPackages (ps: [ps.numpy ps.toolz])).env
``` ```
And then at the command line, just typing `nix-shell` produces the same And then at the command line, just typing `nix-shell` produces the same
@ -229,7 +232,7 @@ What's happening here?
imports the `<nixpkgs>` function, `{}` calls it and the `with` statement imports the `<nixpkgs>` function, `{}` calls it and the `with` statement
brings all attributes of `nixpkgs` in the local scope. These attributes form brings all attributes of `nixpkgs` in the local scope. These attributes form
the main package set. the main package set.
2. Then we create a Python 3.8 environment with the `withPackages` function, as before. 2. Then we create a Python 3.9 environment with the `withPackages` function, as before.
3. The `withPackages` function expects us to provide a function as an argument 3. The `withPackages` function expects us to provide a function as an argument
that takes the set of all Python packages and returns a list of packages to that takes the set of all Python packages and returns a list of packages to
include in the environment. Here, we select the packages `numpy` and `toolz` include in the environment. Here, we select the packages `numpy` and `toolz`
@ -240,7 +243,7 @@ To combine this with `mkShell` you can:
```nix ```nix
with import <nixpkgs> {}; with import <nixpkgs> {};
let let
pythonEnv = python38.withPackages (ps: [ pythonEnv = python39.withPackages (ps: [
ps.numpy ps.numpy
ps.toolz ps.toolz
]); ]);
@ -378,8 +381,8 @@ information. The output of the function is a derivation.
An expression for `toolz` can be found in the Nixpkgs repository. As explained An expression for `toolz` can be found in the Nixpkgs repository. As explained
in the introduction of this Python section, a derivation of `toolz` is available in the introduction of this Python section, a derivation of `toolz` is available
for each interpreter version, e.g. `python38.pkgs.toolz` refers to the `toolz` for each interpreter version, e.g. `python39.pkgs.toolz` refers to the `toolz`
derivation corresponding to the CPython 3.8 interpreter. derivation corresponding to the CPython 3.9 interpreter.
The above example works when you're directly working on The above example works when you're directly working on
`pkgs/top-level/python-packages.nix` in the Nixpkgs repository. Often though, `pkgs/top-level/python-packages.nix` in the Nixpkgs repository. Often though,
@ -392,11 +395,11 @@ and adds it along with a `numpy` package to a Python environment.
with import <nixpkgs> {}; with import <nixpkgs> {};
( let ( let
my_toolz = python38.pkgs.buildPythonPackage rec { my_toolz = python39.pkgs.buildPythonPackage rec {
pname = "toolz"; pname = "toolz";
version = "0.10.0"; version = "0.10.0";
src = python38.pkgs.fetchPypi { src = python39.pkgs.fetchPypi {
inherit pname version; inherit pname version;
sha256 = "08fdd5ef7c96480ad11c12d472de21acd32359996f69a5259299b540feba4560"; sha256 = "08fdd5ef7c96480ad11c12d472de21acd32359996f69a5259299b540feba4560";
}; };
@ -414,7 +417,7 @@ with import <nixpkgs> {};
``` ```
Executing `nix-shell` will result in an environment in which you can use Executing `nix-shell` will result in an environment in which you can use
Python 3.8 and the `toolz` package. As you can see we had to explicitly mention Python 3.9 and the `toolz` package. As you can see we had to explicitly mention
for which Python version we want to build a package. for which Python version we want to build a package.
So, what did we do here? Well, we took the Nix expression that we used earlier So, what did we do here? Well, we took the Nix expression that we used earlier
@ -742,7 +745,7 @@ 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 is a local source, and if the local source has a `setup.py`, then development
mode is activated. mode is activated.
In the following example we create a simple environment that has a Python 3.8 In the following example we create a simple environment that has a Python 3.9
version of our package in it, as well as its dependencies and other packages we 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`. 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 Indeed, we can just add any package we like to have in our environment to
@ -750,7 +753,7 @@ Indeed, we can just add any package we like to have in our environment to
```nix ```nix
with import <nixpkgs> {}; with import <nixpkgs> {};
with python38Packages; with python39Packages;
buildPythonPackage rec { buildPythonPackage rec {
name = "mypackage"; name = "mypackage";
@ -828,9 +831,9 @@ and in this case the `python38` interpreter is automatically used.
### Interpreters {#interpreters} ### Interpreters {#interpreters}
Versions 2.7, 3.7, 3.8 and 3.9 of the CPython interpreter are available as Versions 2.7, 3.7, 3.8, 3.9 and 3.10 of the CPython interpreter are available
respectively `python27`, `python37`, `python38` and `python39`. The as respectively `python27`, `python37`, `python38`, `python39` and `python310`.
aliases `python2` and `python3` correspond to respectively `python27` and The aliases `python2` and `python3` correspond to respectively `python27` and
`python39`. The attribute `python` maps to `python2`. The PyPy interpreters `python39`. The attribute `python` maps to `python2`. The PyPy interpreters
compatible with Python 2.7 and 3 are available as `pypy27` and `pypy3`, with compatible with Python 2.7 and 3 are available as `pypy27` and `pypy3`, with
aliases `pypy2` mapping to `pypy27` and `pypy` mapping to `pypy2`. The Nix aliases `pypy2` mapping to `pypy27` and `pypy` mapping to `pypy2`. The Nix