Steve Marin stevemarin

Emacs, Python, Treesitter and Eglot

Treesitter (“better”/faster syntax highlighting)

Make sure you have Emacs with treesitter support:
M-: (treesit-available-p) RET should return t
Make sure you have installed python treesitter grammar

Method for Emulating Higher-Kinded Types in Rust

Intro

I've been fiddling about with an idea lately, looking at how higher-kinded types can be represented in such a way that we can reason with them in Rust here and now, without having to wait a couple years for what would be a significant change to the language and compiler.

There have been multiple discussions on introducing higher-ranked polymorphism into Rust, using Haskell-style Higher-Kinded Types (HKTs) or Scala-looking Generalised Associated Types (GATs). The benefit of higher-ranked polymorphism is to allow higher-level, richer abstractions and pattern expression than just the rank-1 polymorphism we have today.

As an example, currently we can express this type:

What I did to get Python 3.4.2 on Ubuntu 14.04. The stock version of Python 3 on Ubuntu is 3.4.0. Which is missing some of the best parts! (asyncio, etc). Luckily I discovered pyenv which solved my problem.

Install pyenv

Pyenv (not to be confused with pyvenv) is the Python equivelant of rbenv. It lets you configure which Python environment/version is available per directory, user, or other session variables.

I followed the instructions here to install pyenv in my home directory. Verbatem, those instructions are:

sudo apt-get install git python-pip make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev

	import cityhash

	class Cell:
	"""A cell in the Invertible Bloom Filter."""
	def __init__(self, index, ibf):
	self.index = index
	self.item_sum = 0 # Now just a single integer instead of array
	self.hash_sum = 0 # Store hash sum separately for verification
	self.count = 0
	self.ibf = ibf