Nix is a great tool to set up development environments. It allows us to have simultaneous installations of various versions of tools—such as Python—required for our projects. This means Nix makes it easy to have Python 2.7 installed for one project, and Python 3.6 for another. Projects using the same Python version can have different Python packages.
Of course, Python’s VirtualEnv also enables us to do this. Nix, however, is more powerful. It can handle all our system’s packages; not just Python’s. This means it enables us to hold different versions of any dependency. For example, if one project requires a specific version of OpenCL and another project requires an incompatible version, VirtualEnv won’t help us. Nix will.
There are many Python packages, and to install one such package through Nix requires it to be available in the Nix package repository. Understandably, not all Python packages are packaged for Nix—and those that are, often are not the newest version, nor at some other specific version we require.
We can use Nix to provision a Python environment for our project that works similarly to VirtualEnv’s. We can then use pip to handle such per-project Python dependencies, allowing us to grab Python packages directly from the regular Python package repositories without going through Nix. This also allows us to quickly get to work with others’ Python projects that are not set up to work with Nix.
&SPL is an acronym for Simple Programming Language, and is a C-like imperative programming language, with classes, lists, and tuples. For example, the following code produces the Fibonacci sequence.
// Output the Fibonacci sequence
var t1 = 0;
var t2 = 1;
var h = t1 + t2;
t1 = t2;
t2 = h;
The language is formally defined with a context-free grammar and typing rules. In this post an implementation of an &SPL source code compiler implemented in Haskell will be discussed. The compiler compiles the source code into assembly for a Simple Stack Machine  (http://www.staff.science.uu.nl/~dijks106/SSM/) in a four-part process of lexing, parsing, typing and code generation. The source code is available on GitHub.
When developing applications in Django, the need might arise to customize the user model. Specifically, you might want to create different types of users. In my case, I’m interested in creating a person user and a kit user. A person user can own multiple kit users, and both need to be able to authenticate to access an API. Luckily, Django’s authentication system is very flexible, and there are multiple ways to achieve this goal.
The standard way to implement this is to stick with the default user model, django.contrib.auth.models.User, and create a complex user profile. The profile adds the desired fields and behaviors for the various user types in a new model, and links to the model through a field reference. This can get fairly complex quickly. It is especially difficult to express ownership of kits by users, without allowing ownership of users by users. Here, we will see how we can implement this using inheritance.
Since building a new computer, my Windows 10 installation would sometimes crash. The error reported on the blue screen of death would always be page fault in nonpaged area. Interestingly, the system would be fine for months and then suddenly crash a few times per day — always when using Deluge, a torrent client. After some testing, it turned out that downloading a torrent with Deluge would reliably crash the system within an hour.
Debugging the crash minidump with Windows Debugger (WinDBG), it turned out the driver bcmwl63a was likely at fault. This driver is developed by Broadcom for 802.11 wireless network adapters. The driver was being used for my ASUS PCE-AC68 network adapter.
I was using version 7.35.338.0 of the Broadcom drivers for the adapter, supplied through the ASUS product utility version 126.96.36.199 that is available on the ASUS support website. The issue can be fixed by upgrading to version 7.35.351.0 of the Broadcom drivers, which ASUS supplies in version 188.8.131.52 of their utility. The issue can likely also be fixed by downgrading to version 184.108.40.206 (utility version 220.127.116.11), but I have not tested this. See this thread for more information.
First uninstall the old driver through Windows Device Manger (and uninstall the utility through the Control Panel, if installed). Then, instead of installing the new utility, I would recommend installing only the new driver (supplied in the same zip-file as the utility). This can be done manually in Device Manager by updating driver software for the PCE-AC68. Note that after uninstalling the old drivers, the adapter might show up as an unrecognized device, so be sure to check that if the PCE-AC68 is no longer present in the device list.