Robert Medeiros crimeminister

Introduction

Stuart talking about them as part of the Day of Datomic videos:

Simple data structure

Simple data structure for anomalies.

References

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

	...

	# Fake a fuse install
	RUN apt-get install libfuse2
	RUN cd /tmp ; apt-get download fuse
	RUN cd /tmp ; dpkg-deb -x fuse_* .
	RUN cd /tmp ; dpkg-deb -e fuse_*
	RUN cd /tmp ; rm fuse_*.deb
	RUN cd /tmp ; echo -en '#!/bin/bash\nexit 0\n' > DEBIAN/postinst
	RUN cd /tmp ; dpkg-deb -b . /fuse.deb

	;; Datomic example code

	;; demonstrates various update scenarios, using a news database
	;; that contains stories, users, and upvotes

	;; grab an in memory database
	(use '[datomic.api :only (q db) :as d])
	(def uri "datomic:mem://foo")
	(d/create-database uri)
	(def conn (d/connect uri))

	(ns groupon.joda-instant-reader
	(:require [clojure.instant :as i])
	(:import org.joda.time.DateTime))


	(defmethod print-method org.joda.time.DateTime
	[^org.joda.time.DateTime d ^java.io.Writer w]
	(#'i/print-date (java.util.Date. (.getMillis d)) w))

	(defmethod print-dup org.joda.time.DateTime