JosephPecoraro

# Ways to execute a shell script in Ruby
# Example Script - Joseph Pecoraro

cmd = "echo 'hi'" # Sample string that can be used

# 1. Kernel#` - commonly called backticks - `cmd` 
# This is like many other languages, including bash, PHP, and Perl
#   Synchronous (blocking)
#   Returns the output of the shell command
#   Docs: http://ruby-doc.org/core/classes/Kernel.html#M001111

mboeh

# NOTE: I just slapped this together as a proof of concept. Thread safety etc. is left to the reader.

module RTDocumentation

  def self.included(into)
    # method_added doesn't seem to work if mixed in
    into.send(:define_method, :method_added) do |name|
      if @_rtdoc_nextdoc
        @_rtdocs ||= {}
        @_rtdocs[name.to_s] = @_rtdoc_nextdoc

mboeh

class Snatcher < BasicObject
  
  C = ::Object.new
  class << C
    def abduct_method(meth, arity)
      ObjectSpace.each_object(Module) do |mod|
        next if mod.kind_of? Class
        if mod.instance_methods.include?(meth)
          return mod.instance_method(meth)
        end

kinopyo

Concept

(The blockquote style does not look so well so I just pasted directly, but these are all quoted from the links in the bottom of this page)

You should not implement to_str unless your object acts like a string, rather than just having a string representation. The only core class that implements to_str is String itself.

[to_i and to_s] are not particularly strict: if an object has some kind of decent representation as a string, for example, it will probably have a to_s method… [to_int and to_str] are strict conversion functions: you implement them only if you object can naturally be used every place a string or an integer could be used.

to_str is used by methods such as String#concat to convert their arguments to a string. Unlike to_s, which is supported by almost all classes, to_str is normally implemented only by those classes that act like strings. Of the built-in classes, only Exception and String implement to_str

willurd

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

nellshamrell

All of these resources were extremely valuable as I researched regex, finite state machines, and regex in Ruby.  Check them out, they're full of fantastic information!

Articles
"Exploring Ruby's Regular Expression Algorithm" by Pat Shaughnessy
http://patshaughnessy.net/2012/4/3/exploring-rubys-regular-expression-algorithm

"Finite State Machines and Regular Expressions" by Eli Bendersky
http://www.gamedev.net/page/resources/_/technical/general-programming/finite-state-machines-and-regular-expressions-r3176

"Regular Expression Matching Can Be Simple and Fast" by Russ Cox

rjfranco

Upgrading a PostgreSQL Database

When using homebrew, on OSX

• launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist (old way)
• brew services stop postgresql (new way)
• mv /usr/local/var/postgres /usr/local/var/postgres.old
• initdb /usr/local/var/postgres -E utf8
• pg_upgrade -b /usr/local/Cellar/postgresql/9.3.5_1/bin -B /usr/local/Cellar/postgresql/9.4.0/bin -d /usr/local/var/postgres.old -D /usr/local/var/postgres
• ./delete_old_cluster.sh (automatically generated in current directory)
• rm delete_old_cluster.sh

nellshamrell

Beginning Regex

Intro to Regular Expressions by Michael Fitzgeral
http://www.amazon.com/Introducing-Regular-Expressions-ebook/dp/B008K9OGDA/ref=sr_1_2?ie=UTF8&qid=1374171971&sr=8-2&keywords=Regular+Expressions

Using Regular Expressions in Ruby: Part 1 by Nell Shamrell 
https://www.bluebox.net/insight/blog-article/using-regular-expressions-in-ruby-part-1-of-3

Intermediate Regex

chaitanyagupta

Reader Macros in Common Lisp

This post also appears on lisper.in.

Reader macros are perhaps not as famous as ordinary macros. While macros are a great way to create your own DSL, reader macros provide even greater flexibility by allowing you to create entirely new syntax on top of Lisp.

Paul Graham explains them very well in [On Lisp][] (Chapter 17, Read-Macros):

The three big moments in a Lisp expression's life are read-time, compile-time, and runtime. Functions are in control at runtime. Macros give us a chance to perform transformations on programs at compile-time. ...read-macros... do their work at read-time.

zloedi

// Copyright (c) 2021 Stoiko Todorov
// This work is licensed under the terms of the MIT license.  
// For a copy, see https://opensource.org/licenses/MIT.

//   What this function does:
//      Rasterizes a single Field Of View octant on a grid, similar to the way 
//      field of view / line of sight / shadowcasting is implemented in some 
//      roguelikes.
//      Uses rays to define visible volumes instead of tracing lines from origin 
//      to pixels.