gist:5122217

data StartsWithA a b = StartsWithA a (StartsWithB a b)
                     | EmptyA
                       deriving Show

data StartsWithB a b = StartsWithB b (StartsWithA a b)
                     | EmptyB
                       deriving Show

infixr 7 <<<
infixr 7 >>>

fogus

Chez Scheme

http://www.cs.indiana.edu/~dyb/pubs/hocs.pdf

Precursor systems

• SDP (with Rex Dwyer)
• Z80 Scheme (with George Cohn)
• C-Scheme
• Data General Common Lisp (with Rob Vollum, others)

fogus

#!/usr/bin/env python
# -*-coding: utf8-*-
# Title: chessboard.py
# Author: Gribouillis
# Created: 2012-05-19 22:18:09.909216 (isoformat date)
# License: Public Domain
# Use this code freely.

version_info = (0, 1)
version = ".".join(map(str, version_info))

mtnygard

(ns rxjava-datomic.query
  (:require [datomic.api :as d])
  (:use     [clojure.repl :only [pst]])
  (:import  [rx Observable]
            datomic.Peer))

(defn query [qry & inputs]
  (Observable/toObservable
   (Peer/q qry (object-array inputs))))

mislav

Jim Weirich:

This is how I explain it… Ruby has Procs and Lambdas. Procs are created with Proc.new { }, lambdas are created with lambda {} and ->() {}.

In Ruby 1.8, proc {} creates lambda, and Ruby 1.9 it creates procs (don't ask).

Lambdas use method semantics when handling parameters, procs use assignment semantics when handling parameters.

This means lambdas, like methods, will raise an ArgumentError when called with fewer arguments than they were defined with. Procs will simply assign nil to variables for arguments that were not passed in.

daveray

Links for essays ref'd in http://blog.fogus.me/2009/03/11/seven-books/

• On the Criteria to Be Used in Decomposing Systems Into Modules – David Parnas
• A Note On Distributed Computing – Jim Waldo, Geoff Wyant, Ann Wollrath, Sam Kendall
• The Next 700 Programming Languages – P. J. Landin
• Can Programming Be Liberated from the von Neumann Style? – John Backus
• Reflections on Trusting Trust – Ken Thompson
• Lisp: Good News, Bad News, How to Win Big – Richard Gabriel
• An Experimental Evaluation of the Assumption of Independence in Multiversion Programming – John Knight and Nancy Leveson
• [Arguments and Results –

manuel

;; See http://okmij.org/ftp/continuations/implementations.html#dynamic-wind
;; and http://axisofeval.blogspot.com/2012/08/delimited-continuations-do-dynamic-wind.html

;; Slight trick here: use identity of yield-record-tag function as the actual tag
(define (yield-record-tag) yield-record-tag)
(define (make-yield-record v k)
  (list yield-record-tag v k))

;; Yield simply aborts up to the generator's caller, delivering to it
;; the yielded value and the continuation for resuming after the call

fogus

Emails from Matthew

http://lists.racket-lang.org/users/archive/2005-August/009483.html

http://lists.racket-lang.org/users/archive/2005-November/010350.html

http://lists.racket-lang.org/users/archive/2006-June/013819.html

http://lists.racket-lang.org/users/archive/2006-August/014439.html

fogus

Latency Comparison Numbers
--------------------------
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
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

fogus

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs