bhb

Building a blockchain, assisted by Clojure spec

In an effort to gain at least a superficial understanding of the technical implementation of cryptocurrencies, I recently worked my way through "Learn Blockchains by Building One" using Clojure.

This was a good chance to experiment with using spec in new ways. At work, we primarily use spec to validate our global re-frame state and to validate data at system boundaries. For this project, I experimented with using instrumentation much more pervasively than I had done elsewhere.

This is not a guide to spec (there are already many excellent resources for this). Rather, it's an experience report exploring what went well, what is still missing, and quite a few unanswered questions for future research. If you have solutions for any of the problems I've presented, please let me know!

You don't need to know or care about blockchains to understand the code be

bishboria

These links no longer work. Springer have pulled the free plug.

Graduate texts in mathematics

duplicates = multiple editions

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

brendonanderson

repositories {
  jcenter()
  maven { url "http://repo.spring.io/libs-release" }
}

dependencies {
  ...
  springloaded "org.springframework:springloaded:1.2.3.RELEASE"
  ...
}

ckirkendall

(use '[clojure.core.match :only [match]])

(defn evaluate [env [sym x y]]
  (match [sym]
    ['Number]   x
    ['Add]      (+ (evaluate env x) (evaluate env y))
    ['Multiply] (* (evaluate env x) (evaluate env y))
    ['Variable] (env x)))
    
(def environment {"a" 3, "b" 4, "c" 5})

ironcamel

import java.io.BufferedReader;
import java.io.InputStreamReader;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
public class SimpleRequest {

nikolaplejic

(ns fileupload.core
    (:use [net.cgrand.enlive-html
              :only [deftemplate defsnippet content clone-for
                     nth-of-type first-child do-> set-attr sniptest at emit*]]
          [compojure.core]
          [ring.adapter.jetty])
    (:require (compojure [route :as route])
            (ring.util [response :as response])
            (ring.middleware [multipart-params :as mp])
            (clojure.contrib [duck-streams :as ds]))