karpathy

"""
The most atomic way to train and run inference for a GPT in pure, dependency-free Python.
This file is the complete algorithm.
Everything else is just efficiency.

@karpathy
"""

import os       # os.path.exists
import math     # math.log, math.exp

rrampage

/*
  Compile with one of the following: 
    zig cc -v -s -Os -target aarch64-linux-musl -nostdlib -flto -static shell.c  -o csh
    zig cc -v -s -Os -target aarch64-linux-gnu  -nostdlib -flto -static shell.c  -o csh

	CLANG:
		clang -v -s -Oz -ffreestanding -nostdlib -fno-stack-protector -Wl,--entry=_start -Wl,--gc-sections -Wl,-z,now -flto -static -o csh  shell.c
		musl-clang -v -s -Os -nostdlib -nostartfiles -fno-stack-protector -Wl,--entry=_start -Wl,--gc-sections -Wl,-z,now -flto -nostdinc -static -o csh  shell.c

  GCC (some things DO NOT WORK like `pwd`):

hirrolot

let discard _a b = b

let rec pp lvl = function
  | `Lam f -> "(λ" ^ pp (lvl + 1) (f (`Go lvl)) ^ ")"
  | `Pi (a, f) -> "(Π" ^ pp lvl a ^ "." ^ pp (lvl + 1) (f (`Go lvl)) ^ ")"
  | `Appl (m, n) -> "(" ^ pp lvl m ^ " " ^ pp lvl n ^ ")"
  | `Ann (m, a) -> "(" ^ pp lvl m ^ " : " ^ pp lvl a ^ ")"
  | `Go x -> string_of_int x
  | `Star -> "*"
  | `Box -> "☐"

pizlonator

This document explains how I would implement an SSA-based compiler if I was writing one today.

This document is intentionally opinionated. It just tells you how I would do it. This document is intended for anyone who has read about SSA and understands the concept, but is confused about how exactly to put it into practice. If you're that person, then I'm here to show you a way to do it that works well for me. If you're looking for a review of other ways to do it, I recommend this post.

My approach works well when implementing the compiler in any language that easily permits cyclic mutable data structures. I know from experience that it'll work great in C++, C#, or Java. The memory management of this approach is simple (and I'll explain it), so you won't have to stress about use after frees.

I like my approach because it leads to an ergonomic API by minimizing the amount of special cases you have to worry about. Most of the compiler is analyses and transformations ov

neel-krishnaswami

module C : sig
  type t 
  val empty : t 
  val one : char -> t 
  val union : t -> t -> t 
  val inter : t -> t -> t 
  val top : t 
  val mem : char -> t -> bool 
  val make : (char -> bool) -> t 
  val equal : t -> t -> bool

hirrolot

type term =
  | Lam of (term -> term)
  | Pi of term * (term -> term)
  | Appl of term * term
  | Ann of term * term
  | FreeVar of int
  | Star
  | Box

let unfurl lvl f = f (FreeVar lvl)

swatson555

/* Heap based virtual machine described in section 3.4 of Three Implementation Models for Scheme, Dybvig
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>

char token[128][32];

pdarragh

Approachable PL Papers for Undergrads

On September 28, 2021, I asked on Twitter:

PL Twitter:

you get to recommend one published PL paper for an undergrad to read with oversight by someone experienced. the paper should be interesting, approachable, and (mostly) self-contained.

what paper do you recommend?

p4bl0-

This project is a tiny compiler for a very simple language consisting of boolean expression.

The language has two constants: 1 for true and 0 for false, and 4 logic gates: ! (not), & (and), | (or), and ^ (xor).

It can also use parentheses to manage priorities.

Here is its grammar in BNF format:

expr ::= "0" | "1"

snej

// Tails has grown a bit and moved out into its own repository: https://github.com/snej/tails/
// Please visit it there!
//
// If you want to see the tiny original version from May Forth 2021, it's still here;
// click the "Revisions" button above, or go to:
//   https://gist.github.com/snej/9ba59d90689843b22dc5be2730ef0d49/2d55f844b7622aa117b9275bbc9d189613f7ff7f