Memory-sensitive languages like C++ and Rust use compile-time information to calculate
sizes of datatypes. These sizes are used to inform alignment, allocation, and calling conventions in ways
that improve runtime performance. Modern languages in this setting support generic types, but so far
these languages only allow parameterisation over types, not type constructors. In this article I describe
how to enable parameterisation over arbitrary type constructs, while still retaining compile-time calculation
of datatype sizes.
I’ve been using Agda on NixOS for a while (mostly via agda-mode in Emacs), but I remember it was a bit
difficult to get going the very first time. Hopefully this becomes a searchable reference
to getting it all set up quickly.
In this Twitter thread,
Eugenia Cheng talks about how she presented at a conference for women in STEM, and was
confronted by a white guy who felt ‘called out’ by some of her anecdotes. Apparently, she
described interactions with obnoxious individuals in a professional setting, and noted that
they were all white guys. Ironically, the guy raised the issue in such a way that he was added
to the list of anecdotes.
I remember when I first learned about computer programming, around 2008 or 2009.
I wanted to make games, and asked a search engine. Apparently computer graphics
was way too hard, so I decided I wanted to create browser-based static HTML
games and text-based roguelikes. Having learned that PHP and MySQL exist, I sat
down and brainstormed a setting, classes and roles for characters, and all the
other things that come with fantasy RPGs.
I love bound - it makes De
Bruijn indices mindlessly easy. I also love
for all sorts of whole-program transformations. I think they’re two
indispensible tools for working with programming languages.
Unfortunately, they’re not compatible.
It’s difficult to learn functional programming without hearing about continuations. Often they’re mentioned while talking about boosting the performance of pure functional code, sometimes there’s talk of control flow, and occasionally with ‘time-travel’ thrown in there to make it all seem more obscure. It’s all true, but let’s start from the beginning.
NixOS is a Linux distribution with declarative
configuration management. Your system configuration is specified in a
set of files, and can run a command to update your system to the current
specification. A consequence of this is that your entire system
configuration can be versioned.
Unification is a vital process in the implementation of Hindley-Damas-Milner
type inference. In the original paper
it is mentioned in passing as assumed knowledge, so here is an explanation of
unification in with a little help from the HM type theory.
LINQ is a system that provides a flexible query interface for .NET languages.
It allows a user to write queries over arbitrary data using an in-built
SQL-like syntax. This syntactic sugar is mapped to method calls at compile time,
so any data structure that implements the correct methods can be used with LINQ.
With so many programming languages and frameworks at our disposal, it is
too easy to believe that knowledge of many tools is the defining characteristic
of a good programmer. However, many experienced programmers will assert that
it isn’t the languages you know, but your ability to solve problems that
defines you as a programmer.
Monad transformers combine the functionality of two monads into one. They are often used
as a way to “flatten” nested monads, but are also used to enable interactions between
monads that, when used seperately, would be incredibly difficult to implement.