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@vidarh
vidarh / closures-basic.c
Created December 18, 2009 12:10
A number of ways to implement closures in C, in preparation of an upcoming blog post
#include <stdio.h>
#include <stdlib.h>
struct closure {
void (* call)(struct closure *);
int x;
};
@ghoseb
ghoseb / ns-cheatsheet.clj
Last active April 11, 2024 05:28 — forked from alandipert/ns-cheatsheet.clj
Clojure ns syntax cheat-sheet
;;
;; NS CHEATSHEET
;;
;; * :require makes functions available with a namespace prefix
;; and optionally can refer functions to the current ns.
;;
;; * :import refers Java classes to the current namespace.
;;
;; * :refer-clojure affects availability of built-in (clojure.core)
;; functions.
@pepijndevos
pepijndevos / lazy_sort.clj
Created May 2, 2011 12:49
Lazy sorting implementations in Clojure
(ns lazy-sort)
(defn qsort [[head & tail]]
(when head
(lazy-cat (qsort (filter #(< % head) tail))
[head]
(qsort (remove #(< % head) tail)))))
(defn merge*
[[f1 & r1 :as l1] [f2 & r2 :as l2]]
@chrisroos
chrisroos / gpg-import-and-export-instructions.md
Created September 9, 2011 10:49
Instructions for exporting/importing (backup/restore) GPG keys

Every so often I have to restore my gpg keys and I'm never sure how best to do it. So, I've spent some time playing around with the various ways to export/import (backup/restore) keys.

Method 1

Backup the public and secret keyrings and trust database

cp ~/.gnupg/pubring.gpg /path/to/backups/
cp ~/.gnupg/secring.gpg /path/to/backups/
cp ~/.gnupg/trustdb.gpg /path/to/backups/

or, instead of backing up trustdb...

@alandipert
alandipert / kahn.clj
Last active June 24, 2023 17:59
Kahn's topological sort in Clojure
;; Copyright (c) Alan Dipert. All rights reserved.
;; The use and distribution terms for this software are covered by the
;; Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
;; By using this software in any fashion, you are agreeing to be bound by
;; the terms of this license.
;; You must not remove this notice, or any other, from this software.
(ns alandipert.kahn
(:require [clojure.set :refer [difference union intersection]]))
@hashmal
hashmal / gist:1401335
Created November 28, 2011 18:03
OpenGL 3.2 Core Profile, GLFW, Mac OS X Lion [FIXED]
// The following code doesn't work on Mac OS X Lion
// (I don't know for other platforms):
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <GL/glfw.h>
char *VS = "#version 150\n in vec2 position; void main() {gl_Position = vec4(position, 0.0, 1.0);}";
@lspector
lspector / evolvegeo.clj
Created December 9, 2011 17:27
Clojure code for a simple genetic programming system with trivial geography, for demonstration purposes.
;; Lee Spector (lspector@hampshire.edu) 20111018 - 20111121
(ns evolvegeo
(:require [clojure.zip :as zip]))
;; Like evolvefn.clj (https://gist.github.com/1335696), this this code
;; defines and runs a genetic programming system on the problem
;; of finding a function that fits a particular set of [x y] pairs.
;; Unlike evolvefn.clj, this code incorporates trivial geography
;; (http://hampshire.edu/lspector/pubs/trivial-geography-toappear.pdf).
@rygorous
rygorous / Stats.js
Created April 25, 2012 03:48
Half-space tri rasterizers in JS
// stats.js r9 - http://github.com/mrdoob/stats.js
var Stats=function(){var h,a,r=0,s=0,i=Date.now(),u=i,t=i,l=0,n=1E3,o=0,e,j,f,b=[[16,16,48],[0,255,255]],m=0,p=1E3,q=0,d,k,g,c=[[16,48,16],[0,255,0]];h=document.createElement("div");h.style.cursor="pointer";h.style.width="80px";h.style.opacity="0.9";h.style.zIndex="10001";h.addEventListener("mousedown",function(a){a.preventDefault();r=(r+1)%2;0==r?(e.style.display="block",d.style.display="none"):(e.style.display="none",d.style.display="block")},!1);e=document.createElement("div");e.style.textAlign=
"left";e.style.lineHeight="1.2em";e.style.backgroundColor="rgb("+Math.floor(b[0][0]/2)+","+Math.floor(b[0][1]/2)+","+Math.floor(b[0][2]/2)+")";e.style.padding="0 0 3px 3px";h.appendChild(e);j=document.createElement("div");j.style.fontFamily="Helvetica, Arial, sans-serif";j.style.fontSize="9px";j.style.color="rgb("+b[1][0]+","+b[1][1]+","+b[1][2]+")";j.style.fontWeight="bold";j.innerHTML="FPS";e.appendChild(j);f=document.createElement("div");f.style.position="relati
@stuarthalloway
stuarthalloway / gist:2645453
Created May 9, 2012 15:22
Datomic queries against Clojure collections
;; Datomic example code
(use '[datomic.api :only (db q) :as d])
;; ?answer binds a scalar
(q '[:find ?answer :in ?answer]
42)
;; of course you can bind more than one of anything
(q '[:find ?last ?first :in ?last ?first]
"Doe" "John")
@jboner
jboner / latency.txt
Last active May 6, 2024 07:06
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD