ajchemist

/*
 This software is Copyright (c) 2010
 Michael Wild. All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

 - Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.

ajchemist

고수준에서 암호학 이해하기

이 글은 메아리 저널에 쓸 목적으로 한동안 작업하던 글입니다. 메아리 특유의 디자인(...)이 싫다면 여기로 링크하셔도 됩니다. 어느 쪽이든간에 의견은 이 아래의 코멘트 란 또는 메아리에 기재되어 있는 메일 주소를 써 주시면 감사하겠습니다. --lifthrasiir

암호학을 사용하는 많은 시스템은 세부적으로 무슨 알고리즘을 쓰는지보다는 그 알고리즘들이 어떻게 연결되어 있는지, 즉 구조가 실제 안전성에 더 큰 영향을 미친다. 따라서 구조와 그 구조를 이루는 빌딩 블럭을 아는 것이 중요한데, 여기에서는 이러한 암호학적 빌딩 블럭과 함께 블럭들이 어떻게 쓰여서 더 큰 구조를 만드는지를 알아 본다.

Key Exchange

키 교환. 두 사람만이 알 수 있는 새로운 키를 만든다. 이 과정이 끝나도 상대방이 내가 아는 사람인진 알 수 없지만 적어도 상대방과 내가 같은 키를 가지고 있다는 건 확신할 수 있다.

ajchemist

(defn ->kebab [s]
  (str/join "-" (map str/lower-case (re-seq #"\w[a-z]+" s))))

(def components '[Card AppBar LeftNav CardTitle])

(defn gen-wrapper [component]
  `(defmacro ~(symbol (->kebab (str component))) [& args#]
     (let [[opts# & [children#]] (if (-> args# first map?)
                                   [(first args#) (rest args#)]
                                   [nil args#])]

ajchemist

javascript: (function(e, t) {
    var n = e.document;
    setTimeout(function() {
        function a(e) {
            if (e.data === "destroy_bookmarklet") {
                var r = n.getElementById(t);
                if (r) {
                    n.body.removeChild(r);
                    r = null
                }

ajchemist

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors

ajchemist

CSS Layout Debugger

A tweet-sized debugger for visualizing your CSS layouts. Outlines every DOM element on your page a random (valid) CSS hex color.

One-line version to paste in your DevTools

Use $$ if your browser aliases it:

~ 108 byte version

ajchemist

; A REPL-based, annotated Seesaw tutorial
; Please visit https://github.com/daveray/seesaw for more info
;
; This is a very basic intro to Seesaw, a Clojure UI toolkit. It covers
; Seesaw's basic features and philosophy, but only scratches the surface
; of what's available. It only assumes knowledge of Clojure. No Swing or
; Java experience is needed.
;
; This material was first presented in a talk at @CraftsmanGuild in
; Ann Arbor, MI.

ajchemist

A little Clojure configuration reader

This is a handy bit of code I've written more than once. I thought I'd throw it in here so I can refer back to it later. Basically, it lets you read a config file to produce a Clojure map. The config files themselves can contain one or more forms, each of which can be either a map or a list. Maps are simply merged. Lists correspond to invocations of extension points, which in turn produces a map, which is merged along with everything else.

An Example

Consider the following files:

names.edn

ajchemist

;;
;; 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.

ajchemist

Lisp interpreter in 90 lines of C++

I've enjoyed reading Peter Norvig's recent articles on Lisp. He implements a Scheme interpreter in 90 lines of Python in the first, and develops it further in the second.

Just for fun I wondered if I could write one in C++. My goals would be

1. A Lisp interpreter that would complete Peter's Lis.py test cases correctly...
2. ...in no more than 90 lines of C++.

Although I've been thinking about this for a few weeks, as I write this I have not written a line of the code. I'm pretty sure I will achieve 1, and 2 will be... a piece of cake!