Mike Tang miketang84

Document moved to: https://github.com/servo/servo/blob/master/HACKING_QUICKSTART.md

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:

	//! Source file for the `game` crate.
	#![allow(dead_code)]

	/// The `Player` trait.
	pub trait Player {
	/// Gets called when it's time for this player to take their turn.
	///
	/// The game is played by sending commands on `pipe` and checking
	/// the responses that are returned.
	fn take_turn(&self, pipe: &PlayerActionPipe, round: uint);

	"""
	Minimal character-level Vanilla RNN model. Written by Andrej Karpathy (@karpathy)
	BSD License
	"""
	import numpy as np

	# data I/O
	data = open('input.txt', 'r').read() # should be simple plain text file
	chars = list(set(data))
	data_size, vocab_size = len(data), len(chars)