staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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csfrancis

# Updated for Ruby 2.3
string_t = None

def get_rstring(addr):
  s = addr.cast(string_t.pointer())
  if s['basic']['flags'] & (1 << 13):
    return s['as']['heap']['ptr'].string()
  else:
    return s['as']['ary'].string()

lelandbatey

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results

gabetax

rspec expect syntax and stand-alone operator matches

I recently started a new project using rspec's newer (and soon to be default) expect syntax, and encountered this error:

expect(5).to == 5
ArgumentError: The expect syntax does not support operator matchers, so you must pass a matcher to `#to`

"Why'd they take out operator matches? I've grown quite accustomed to them!", I thought. Digging around, the source of this change started in pull request 119 citing issue 138 as one of the root causes. Here's what's actually happening:

mganucheau

// LPD8806 LED Code for our Yacht Club's Anchor 
/*************************************************************************************/
#include "LPD8806.h" // Library Here: https://github.com/adafruit/LPD8806
#include "SPI.h"

int totalLEDs = 14;
int dataPin = 2;    
int clockPin = 3; 

LPD8806 strip = LPD8806(totalLEDs, dataPin, clockPin);

jashkenas

# MAC manipulators
alias random_mac='sudo ifconfig en0 ether `openssl rand -hex 6 | sed "s/\(..\)/\1:/g; s/.$//"`'
alias restore_mac='sudo ifconfig en0 ether YOUR_ORIGINAL_MAC_ADDRESS_GOES_HERE'

ryanb

My issues with Modules

In researching topics for RailsCasts I often read code in Rails and other gems. This is a great exercise to do. Not only will you pick up some coding tips, but it can help you better understand what makes code readable.

A common practice to organize code in gems is to divide it into modules. When this is done extensively I find it becomes very difficult to read. Before I explain further, a quick detour on instance_eval.

You can find instance_eval used in many DSLs: from routes to state machines. Here's an example from Thinking Sphinx.

class Article < ActiveRecord::Base

theaboutbox

--type-add=css=.sass,.less,.scss
--type-add=ruby=.rake,.rsel,.builder,.thor
--type-add=html=.haml,.html.erb,.html.haml
--type-add=js=.js.erb,.coffee
--type-set=cucumber=.feature
--type-set=c=.c,.cpp,.ino,.pde,.h
--ignore-dir=vendor
--ignore-dir=log
--ignore-dir=tmp
--ignore-dir=doc

pettyjamesm

require 'monitor'
class Semaphore
  def initialize(maxval = nil)
    maxval = maxval.to_i unless maxval.nil?
    raise ArgumentError.new("Semaphores must use a positive maximum value or have no maximum!") if maxval and maxval <= 0
    @max   = maxval || -1
    @count = 0
    @mon   = Monitor.new
    @dwait = @mon.new_cond
    @uwait = @mon.new_cond

josevalim

Sinatra like routes in Rails controllers

A proof of concept of having Sinatra like routes inside your controllers.

How to use

Since the router is gone, feel free to remove config/routes.rb. Then add the file below to lib/action_controller/inline_routes.rb inside your app.