Ruby is amazing. It has a huge standard library and a core choc full of weird and wonderful things. In this talk, given at the Ipswich Ruby User Group, I give a whimsical nonstop tour through some of the more obscure parts of Ruby.

1. HIDDEN TREASURES
of
RUBY
@MrJaba - iprug - 6th Dec 2011

2. Whistlestop tour through the lesser
known/obscure features of Ruby

3. Ruby has a
HUGE
standard library

4. Have you heard of?
Struct
OpenStruct
OptionParser
Abbrev
Benchmark
Find
English

5. Did you know about?
String#squeeze
String#count
String#tr
Kernel#Array
Kernel#trace_var

6. This is just for FUN

7. Core Ruby

8. STRING
#squeeze
“Uh oh the cat sat on the keeeeeeeeeee”.squeeze
=>
“Uh oh the cat sat on the ke”
“oh craaaapppp my aaappp keys are bloody
broken”.squeeze(“ap”)
=>
“oh crap my ap keys are bloody broken”

9. STRING
#count
“FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS.”
How many F’s are there?

10. STRING
#count
“FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS.”.count(“F”)
=>
6

11. STRING
#count
“how many woods would a wood chuck chuck if a
wood chuck could chuck wood?”.count(“a-z”, “^u”)
=>
52

12. “DYTSMH”
.tr(“DYTSMH”, “STRING”)
“STRING”
.tr(“R-T”, “F”)
“FFFING”

13. KERNEL
#Array
yesthat’sacapitalletter
Array(1..3) + Array(args[:thing])
=
[1,2,3, “Thing”]
thing.to_a
=
NoMethodError: undefined method `to_a' for
thing:String

14. KERNEL
#at_exit
at_exit { p ObjectSpace.count_objects }
=
{:TOTAL=31479, :FREE=4687, :T_OBJECT=1442, :T_CLASS=859, :T_MODULE=32, :T_FLOAT=7,
:T_STRING=18190, :T_REGEXP=168, :T_ARRAY=3657, :T_HASH=134, :T_STRUCT=1, :T_BIGNUM=2,
:T_FILE=6, :T_DATA=1210, :T_MATCH=100, :T_COMPLEX=1, :T_NODE=949, :T_ICLASS=34}
at_exit {
loop do
p “unkillable code!”
end }

15. KERNEL
#set_trace_func
class Cheese
def eat
p “om nom nom”
end
end
set_trace_func proc {|event, file, line, id, binding, classname|
p “#{event}, #{file}, #{line}, #{id}, #{binding}, #{classname}”
}
=
c-return, cheese.rb, 9, set_trace_func, #Binding:0x007fe11b84e488, Kernel
line, cheese.rb, 11, , #Binding:0x007fe11b84e1e0,
c-call, cheese.rb, 11, new, #Binding:0x007fe11b84dfb0, Class
c-call, cheese.rb, 11, initialize, #Binding:0x007fe11b84dc90, BasicObject
c-return, cheese.rb, 11, initialize, #Binding:0x007fe11b84da38, BasicObject
c-return, cheese.rb, 11, new, #Binding:0x007fe11b84d808, Class
line, cheese.rb, 12, , #Binding:0x007fe11b84d5d8,
call, cheese.rb, 2, eat, #Binding:0x007fe11b84d3a8, Cheese
line, cheese.rb, 3, eat, #Binding:0x007fe11b84d150, Cheese
c-call, cheese.rb, 3, p, #Binding:0x007fe11b84cef8, Kernel
c-call, cheese.rb, 3, inspect, #Binding:0x007fe11b84ccc8, String
c-return, cheese.rb, 3, inspect, #Binding:0x007fe11b84ca48, String
om nom nom
c-return, cheese.rb, 3, p, #Binding:0x007fe11b84c7f0, Kernel
return, cheese.rb, 4, eat, #Binding:0x007fe11b84c5c0, Cheese

16. Struct
Point = Struct.new :x, :y do
def distance(point)
Math.sqrt((point.x - self.x) ** 2 +
(point.y - self.y) ** 2)
end
end

17. Why? Struct
Quickly define a class with a few known fields
Automatic Hash key
Mitigate risk of spelling errors on field names

18. Ruby
STANDARD
LIBRARY

19. 113 Packages

20. OptionParser
require ‘optparse’
options = {}
parser = OptionParser.new
parser.on(-i, --ipswich, description of IP) {|val| options[:ipswich] = val }
parser.on(-r=ARG, --ruby, Mandatory Argument) {|val| options[:ruby] = val }
parser.on(-u=[ARG], --user, Optional Argument) {|val| options[:user] = val }
parser.on(-g=ARG, --group, Integer, Type cast Argument) {|val| options[:group] = val }
unmatched = parser.parse(ARGV)
puts parser.to_s
puts options are #{options.inspect}
puts unmatched are #{unmatched.inspect}

21. Abbrev
require ‘abbrev’
Abbrev::abbrev(['Whatever'])
{Whateve=Whatever, Whatev=Whateve
Whate=Whatever, What=Whatever,
Wha=Whatever, Wh=Whatever,
W=Whatever, Whatever=Whatever}
Thereisno“whatevs”inthere!

22. Benchmark
require ‘benchmark’
puts Benchmark.measure { calculate_meaning_of_life }
=
0.42 0.42 0.42 ( 4.2)
ElapsedRealTime
UserCPU Sum
SystemCPU
Benchmark.bmbm do |x|
x.report(sort!) { array.dup.sort! }
x.report(sort) { array.dup.sort }
end
=
user system total real
sort! 12.959000 0.010000 12.969000 ( 13.793000)
sort 12.007000 0.000000 12.007000 ( 12.791000)

23. English
require ‘English’
$ERROR_INFO $! $DEFAULT_OUTPUT $
$ERROR_POSITION $@ $DEFAULT_INPUT $
$FS $; $PID $$
$FIELD_SEPARATOR $; $PROCESS_ID $$
$OFS $, $CHILD_STATUS $?
$OUTPUT_FIELD_SEPARATOR $, $LAST_MATCH_INFO $~
$RS $/ $IGNORECASE $=
$INPUT_RECORD_SEPARATOR $/ $ARGV $*
$ORS $ $MATCH $
$OUTPUT_RECORD_SEPARATOR $ $PREMATCH $`
$INPUT_LINE_NUMBER $. $POSTMATCH $'
$NR $. $LAST_PAREN_MATCH $+
$LAST_READ_LINE $_

24. Find
require ‘find’
Find.find(“/Users/ET”) do |path|
puts path
Find.prune if path =~ /hell/
end
= Geddit?
/Users/ET/phone
/Users/ET/home

25. Profiler__
require ‘profiler’
Profiler__::start_profile
complicated_method_call
Profiler__::stop_profile
Profiler__::print_profile($stdout)
% cumulative self self total
time seconds seconds calls ms/call ms/call name
0.00 0.00 0.00 1 0.00 0.00 Integer#times
0.00 0.00 0.00 1 0.00 0.00 Object#complicated_method_call
0.00 0.01 0.00 1 0.00 10.00 #toplevel

26. RSS
require ‘rss/2.0’
response = open(http://feeds.feedburner.com/MrjabasAdventures).read
rss = RSS::Parser.parse(response, false)
rss.items.each do |item|
p item.title
end

27. MiniTest
require ‘minitest/autorun’
describe Cheese do
before do
@cheddar = Cheese.new(“cheddar”)
end
describe when enquiring about smelliness do
it must respond with a stink factor do
@cheddar.smelliness?.must_equal 0.9
end
end
end
Provides:
Specs Mocking Stubbing Runners Benchmarks

28. Thank you to
everyone involved in
Ruby!