ruby -x demo.out

Hello,

This is a run down of the tips from the Aloha Ruby Conf
You can see the ruby embedded in this file.

The -x flag is cool, I build this blog using Jekyll and with the -x flag I can
actually execute this post!

#!/usr/bin/env ruby

# programmatically turn on warnings
$VERBOSE = true

# set this before any 'require' lines to get a hash of files and lines
# dynamically loaded
SCRIPT_LINES__ = { }

require "logger"

puts "Tested this shizzle ... and it worked"

# DATA io handle is created when Ruby sees "__END__"
# You can play with it
DATA.rewind
DATA.each do |l|
  puts "   Line from a rewind: #{l}"
end

# Here we use DATA to get a lock on the file, so it is only run once!
DATA.flock(File::LOCK_EX | File::LOCK_NB) or abort "Already running"
trap("INT", "EXIT")
puts "runnning..."
2.times do |i|
  sleep 1;
  puts "  looping #{i}"
end

if ( SCRIPT_LINES__ ) then
  puts "This is dynamically loaded code: #{SCRIPT_LINES__.inspect}"
end


puts " We can run ruby with the following options:

  --dump parsetree
  --dump parsetree_with_comment
  --dump insns
  --dump yydebug

"

#Autovivication
deep = Hash.new { |hash, key| hash[key] = Hash.new(&hash.default_proc) }
deep[:a][:b][:c]
puts "Autovivication: #{deep}"

str = "Prices: $127.12 $12.34 - They are cheap!"
puts str[/\$(?<dollars>\d+)/, :dollars]
puts str[/\w+?/]

# sprintf type formatting in 1.9
def show_off(name, content)
  puts " %s : %p " % [name, content];
end
show_off "PercentP does .inspect", {"grays" => %w[Jim Joe Ben] }

#puts "%<item>-%<item_size>s | %<price>#{price_size}s" % { item: "Item", price: "Price"}

# Tips:
puts "Hash  - Use .fetch     .. it has better warnings and you can give it default value/block"
puts "Array - Use .zip       .. you can move through multiple arrays in lock step"
puts "Array - Use .partition .. you can split up an array with a block that runs a yes/no"
puts "Array - Use .flat_map  .. if the values are Array's, it flattens then and you just see the all values"

# Array  things - .take and .drop
numbers = 1..10
p numbers.take(3)
p numbers.drop(3)
p numbers.take_while { |n| n <= 5 }
p numbers.drop_while { |n| n <= 5 }

# Array - .cycle is cool! (cycles basically returns a enumberator that just aways goes through array)
who = %w{ben jim}.cycle
(1 .. 10).each  do |n|
  puts " #{who.next} gets #{n} sweets "
end