tavisrudd

Lazy, infinite recursive sequences in Bash (like in Haskell, if you squint).

I was inspired by the beautiful Haskell zipWith implementation of the Fibonacci sequence `fibs = 0 : 1 : zipWith (+) fibs (tail fibs)`
to find an equivalent in bash using 'coroutines' and recursive pipes.

My original experiments were https://twitter.com/tavisrudd/status/367164339716751360
"fun w/ recursive pipes: e=echo;mkfifo fib;{ $e 0 1 1 >fib &};{ while read i j k; do $e $i >&2; $e $j $k $(($j+$k));sleep .4; done;}<fib>fib"

and https://twitter.com/tavisrudd/status/367142071489937408
"o=ouro;b=boros;mkfifo $o$b;e=echo; { $e $o > $o$b & }; { while read s;do $e $s>&2;case $s in $o)$e $b;;*)$e $o; esac; done; }<$o$b >$o$b"

howardabrams

(defun remote-shell-fav-hosts-get ()
  "My hook to the remote-shell processes in order to connect to
    my OpenStack controller, and create a hashtable of host names as
    the keys, and IP addresses as the values."
  (interactive)

  ;; Run nova list command remotely on this host system, and put the
  ;; results in a temp buffer:
  (let* ((undercloud-controller "10.98.1.145")
         (default-directory    (format "/ssh:%s:" undercloud-controller))

gmorpheme

(ns ^{:doc "Evaluator from ch1 of lisp in small pieces. Warning:
  NON-IDIOMATIC clojure!"}
  lisp.chapter1.eval
  (:refer-clojure :exclude [extend]))

(defn wrong [& msgs]
  (throw (RuntimeException. (apply str msgs))))

;; -- runtime support, environments are represented as a seq of pairs,
;; -- stored in an atom. Non-idiomatic but faithful to the book.

lkuper

#lang racket

;; A solver for the following puzzle:
;; Given 5 integers a, b, c, d, and e,
;; find an expression that combines a, b, c, and d with arithmetic operations (+, -, *, and /) to get e.

(require srfi/1)

(define ops '(+ - * /))

swlaschin

(*
This script analyzes the dependencies between top level types in a .NET Assembly.
It is then used to compare the dependency relationships in some F# projects with those in some C# projects.

Note that no attempt has been made to optimize the code yet! 

REQUIRES:

* Mono.Cecil for code analysis
  From http://www.mono-project.com/Cecil#Download 

aztek

Require Import Coq.Program.Basics.
Require Import Coq.Program.Syntax.
Require Import Coq.Init.Datatypes.
Require Import Coq.Unicode.Utf8.

Open Local Scope program_scope.
Open Local Scope list_scope.
Open Local Scope type_scope.

Class Functor (φ : Type → Type) := {

floriandejonckheere

# This entry boots an Antergos (Arch) Linux ISO straight from disk.
# LVM is not supported because the lvm module is not loaded in Antergos initrd

menuentry "Antergos Minimal ISO 2015-09-13" {
        insmod part_gpt
        insmod lvm
        insmod loopback
        set root=(hd0,0)
        set isofile=/antergos.iso
        search --no-floppy --file ${isofile} --set

heppu

Create bootable USB

dd bs=4M if=/path/to/archlinux.iso of=/dev/sdx status=progress oflag=sync

Boot from USB and set prepare system

loadkeys <your-keymap>

pathikrit

/**
 * Solves the n-Queen puzzle in O(n!)
 * Let p[r] be the column of the queen on the rth row (must be exactly 1 queen per row)
 * There also must be exactly 1 queen per column and hence p must be a permuation of (0 until n)
 * There must be n distinct (col + diag) and n distinct (col - diag) for each queen (else bishop attacks)
 * @return returns a Iterator of solutions 
 *     Each solution is an array p of length n such that p[i] is the column of the queen on the ith row
 */
def nQueens(n: Int): Iterator[Seq[Int]] = 
  (0 until n)

CAFxX

📂 Persistent "pipes" in Linux

In a project I'm working on I ran into the requirement of having some sort of persistent FIFO buffer or pipe in Linux, i.e. something file-like that could accept writes from a process and persist it to disk until a second process reads (and acknowledges) it. The persistence should be both across process restarts as well as OS restarts.

AFAICT unfortunately in the Linux world such a primitive does not exist (named pipes/FIFOs do not persist