liaden

letters = "ABCDEFGHIJKLMNOPRSTUVWXYZ"
map = {}

letters.each_char.each_with_index do |c, i|
  map[c] = letters[(i+13)%26]
end

map.keys.each do |k|
 map[k.downcase] = map[k].downcase
end

liaden

class Object
  # as inspired by bash
  def tee(*functions)
    self.tap do
      args.map { |arg| arg.call(self) }
    end
  end
end
class SomeClass

liaden

# before

class X
  # imperative, affects system state, depends on globals
  def self.x
    puts Config.data
  end
end

X.x

liaden

def find_column_in_tables(filter)
  tables = ActiveRecord::Base.connection.tables.map { |tname| tname.singularize.camelize.constantize rescue nil }.compact
  column_names_by_table = tables.reduce({}) { |hash, table| hash.merge( table.name =>  table.column_names ) }
  column_names_by_table.select { |key,value| value.any? { |column_name| column_name =~ filter } }
end

liaden

require 'active_record'
require 'sqlite3'

ActiveRecord::Base.establish_connection(
 adapter:  'sqlite3',
 database: ':memory:'
)


ActiveRecord::Schema.define do

liaden

class Maybe
  def initialize(item, &block)
     @item = item
     @block = block || proc { |item| !item.nil? }
   end
  def just
     yield(@item) if @block.call(@item)
  end
end
Maybe.new(5).just { |x| puts x }

liaden

class X
  attr_accessor :x

  def f
    self.x = 2
    if false
      # try commenting out x=0 to see what happens.
      x = 0
    end

liaden

h1 = Hash.new { |h,k| h[k] = Hash.new(&h.default_proc) }.with_indifferent_access
h2 = h1.dup

h1['x']['y']['a'] = 5
h1['x']['y']['arr'] = [1,2,3]
h2['x']['y']['arr'] = [2,3,4]
h1['h'] = [1,2]
h2['f'] = [3,4]

h1.deep_merge!(h2) { |key, old_value, new_value| (Array(old_value) + Array(new_value)).uniq }

liaden

def level(hash, index)
  if level == 1
    return if block_given?
      yield hash.values
    else
      hash.values
    end
  end
  # or hash.values.reduce(Set.new) ....
  hash.values.map { |subhash| level(subhash, index-1) }.flatten.uniq

liaden

/**********************************************************************
  gc.c -
  $Author$
  $Date$
  created at: Tue Oct  5 09:44:46 JST 1993
  Copyright (C) 1993-2003 Yukihiro Matsumoto
  Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
  Copyright (C) 2000  Information-technology Promotion Agency, Japan
**********************************************************************/