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Erik Osheim non

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non / half.scala
Last active Jun 10, 2022
Scala implementation of 16-bit floating point numbers. Also, a test prgoram.
View half.scala
package half
import scala.math.{pow, round, signum}
import scala.util.Random.nextInt
import java.lang.{Float => JFloat}
* Float16 represents 16-bit floating-point values.
* This type does not actually support arithmetic directly. The
non /
Last active Apr 5, 2022
Simple example of using seeds with ScalaCheck for deterministic property-based testing.


ScalaCheck 1.14.0 was just released with support for deterministic testing using seeds. Some folks have asked for examples, so I wanted to produce a Gist to help people use this feature.

simple example

These examples will assume the following imports:

non /
Created Mar 12, 2015
Gödel's fourteen point outline of his philosophical views.

Gödel left in his papers a fourteen-point outline of his philosophical beliefs, that are dated around 1960. They show his deep belief in the rational structure of the world. Here are his 14 points:

  1. The world is rational.
  2. Human reason can, in principle, be developed more highly (through certain techniques).
  3. There are systematic methods for the solution of all problems (also art, etc.).
  4. There are other worlds and rational beings of a different and higher kind.
  5. The world in which we live is not the only one in which we shall live or have lived.
  6. There is incomparably more knowable a priori than is currently known.
  7. The development of human thought since the Renaissance is thoroughly intelligible (durchaus einsichtige).
  8. Reason in mankind will be developed in every direction.
non /
Last active Feb 20, 2022
I feel like conversations around laws and lawfulness in Scala are often not productive, due to a lack of rigor involved. I wanted to try to be as clear and specific as possible about my views of lawful (and unlawful) behavior, and what I consider a correct and rigorous way to think about laws (and their limits) in Scala.


A law is a group of two or more expressions which are required to be the same. The expressions will usually involve one or more typed holes ("inputs") which vary.

Some examples: === x

What is the appeal of dynamically-typed languages?

Kris Nuttycombe asks:

I genuinely wish I understood the appeal of unityped languages better. Can someone who really knows both well-typed and unityped explain?

I think the terms well-typed and unityped are a bit of question-begging here (you might as well say good-typed versus bad-typed), so instead I will say statically-typed and dynamically-typed.

I'm going to approach this article using Scala to stand-in for static typing and Python for dynamic typing. I feel like I am credibly proficient both languages: I don't currently write a lot of Python, but I still have affection for the language, and have probably written hundreds of thousands of lines of Python code over the years.

non / grep.tal
Last active Feb 10, 2022
Regex implementation in Uxntal. Includes a simple grep implementation was well as a REPL for testing.
View grep.tal
( grep.tal )
( )
( by d_m )
( print a character to STDOUT )
%emit { #18 DEO }
( the first argument to grep is the regex )
( arguments are passed on STDIN, so we just )
( assume the first "line" is the argument )
View tal-mode.el
;; tal-mode.el
;; by d_m
;; use rx for regular expressions
(require 'rx)
;; set up a mode hook (currently unused)
(defvar tal-mode-hook nil)
non / maze.tal
Last active Dec 9, 2021
Prototype maze generator for the UXN virtual machine.
View maze.tal
( maze.tal )
( )
( mazes generated by randomized depth-first search )
( press any key to generate a new maze )
( )
( generator uses a simple 16-bit xorshift RNG )
( based on )
%DEBUG { #ff #0e DEO }
%<<5 { #50 SFT2 }
View rng.tal
( rng.tal )
( simple 16-bit xorshift RNG )
( based on )
%<<5 { #50 SFT2 }
%>>1 { #01 SFT2 }
%>>3 { #03 SFT2 }
%RTN { JMP2r }
%EMIT { #18 DEO }
%DIGIT { #00 SWP ;digits ADD2 LDA EMIT }
non /
Created Dec 2, 2012
python calculator
# by Erik Osheim
# This program uses a recursive descent, LL1 parser to generate a Code object
# for the given input. Code objects are pure expressions whose behavior can
# only be controlled via a dictionary of strings-to-numbers provided to run.
# Syntax: