Skip to content

Instantly share code, notes, and snippets.

stevecj / flatten-it.rb
Last active March 30, 2016 08:49
Coding exercise: Flatten an array in Ruby w/o using `Array#flatten`
module ArrayUtils
def self.flatten(array, result=[])
array = Array(array)
array.each do |entry|
case entry
when Array
flatten entry, result
result << entry
stevecj / gist:9ace6a70370f6d1a1511
Last active December 2, 2019 06:34
Ruby will destructure objects that are not arrays, but respond to #to_ary,:b)
ss = [,2),,4)]
p{|a,b| "#{a} #{b}" }
# => ["#<struct S a=1, b=2> ", "#<struct S a=3, b=4> "]
class S ; def to_ary ; to_a ; end ; end
p{|a,b| "#{a} #{b}" }
# => ["1 2", "3 4"]
stevecj / reversible_queue.rb
Last active August 29, 2015 14:10
ReversibleQueue: Works much like Ruby's native Queue, but provides an #undeq method, which Ruby's own Queue does not have
# Works much like Ruby's native Queue, but provides an #undeq
# method, which Ruby's own Queue does not have.
class ReversibleQueue
def initialize
@queue_array = []
@threads_waiting = []
@mutex =
# Push an object onto the tail of the queue
stevecj / colortest
Created July 29, 2014 16:50
ANSI color test written in Ruby
#!/usr/bin/env ruby
ColorNameSequence = %w[
stevecj / require_limit_for_mysql_text.rb
Last active August 29, 2015 14:03
Require a :limit option for MySQL text columns created in Rails 3 app so don't unintentionally make 64K column that silently truncates.
# == config/initializers/require_limit_for_mysql_text.rb ==
# Fail when an attempt is made to specify a MySQL text
# columnn in a migration without providing a :limit value.
# This helps to prevent accidentally defining a 64K column
# (default) when a 16MB or 4GB coumn is desired.
# Note that MySQL silently truncates the data when it is
# too long for the column, so problems are only apparent
# later when attempting to retrieve the data (if then).
stevecj / n-is-the-loneliest-number.txt
Last active September 10, 2015 15:02
(n) is the Loneliest Number
One is the loneliest number that you'll ever do
Two can be as bad as one, well it's the loneliest number since the number one
Three is really not so bad, but it can still be lonely, and that's really sad
Four is really no big deal, so if you think it's lonely, then you'd best get real
Five is practically a crowd, and if you're tryin' to think, it can seem really loud.
Five is the loneliest number
Five is the loneliest number
Five is the loneliest number since the number four dum dum-dum dum-dum
stevecj / yaml_value_extraction_benchmarks.rb
Last active August 29, 2015 13:57
Benchmarking of ways of extracting single value from large YAML map (e.g. ActiveRecord serialized data)
require 'yaml'
require 'benchmark'
def make_yaml_string(num_entries=500)
entry_nums = (0...num_entries).to_a
result = ''
entry_nums.each do |n|
result << "something_#{n}: #{Random.rand}\n"
stevecj / trinary.rb
Last active August 29, 2015 13:57
Stoopid Ruby trick <g>
class Trinary
class << self
def ~ ; ~new ; end
def -@ ; -new ; end
def +@ ; +new ; end
def initialize(digits=[])
@digits = digits
stevecj / deferred_uniqueness_validations.rb
Created March 7, 2013 21:32
Allow any ActiveRecord uniqueness validation(s) to be deferred, and only check after a failed save due to uniqueness violation error from the database.
# ./config/initializers/deferred_uniqueness_validations.rb
# This initializer adds support for deferred processing of
# ActiveRecord uniqueness validations. When a uniqueness
# validation is deferred using the :deferred => true option, it is
# not checked before save. Instead, if there is a uniqueness
# constraint defined for the column in the database, and if the
# save operation raises an ActiveRecord::RecordNotUnique
# exception, then the validation is performed so that the precise
# cause can be determined and the appropriate error information
stevecj / fiber_demo.rb
Created February 4, 2013 05:53
A demonstration of transfer of control to/from a Fiber in Ruby 1.9.x.
fib = do |val|
puts ' -- 2 --'
puts 'fiber started & got: ' + val
puts 'now yield with "1st yield"'
val = Fiber.yield('fiber yield 1')
puts ' -- 4 --'
puts '1st yield got: ' + val
puts 'now yield with "2nd yield"'