Ruby

@Ruby

Running the profiler

ruby -rprofile script.rb

get machine instructions

ruby --dump insns script.rb

See how commands are parsed

ruby --dump parsetree_with_comment script.rb

Abort on thread errors

Thread.abort_on_exception = true

Thread.new do
  fail 'Cannot continue'
end

loop do
  sleep
end

Syntax cheatsheet

class Thing
  attr_accessort :foo
  def initialize(foo = 0)
    @foo = foo
  end
  
  private
  
  def bar
    puts "whoa"
  end
end

if val = 42
  #do stuff
elsif val = 33
  #do stuff
else
  #do stuff
end

# Ternary operator
exp ? true : false

begin
  # try to do this
rescue Exception
  # oh crap
else
  # whatever else
ensure
  # do this no matter what
end

case thing
when 3
  puts 'fizz'
when 5
  puts 'buzz'
else
  puts thing
end

Running proceses

system() - return value of true (zero exit), false (non-zero), and nil (failed execution)
backticks - returns STDOUT, sets $? to the process status
exec() - replace current process by running command

% Notation

Modifier	Meaning
%i[ ]	Non-interpolated symbol array (Ruby 2+)
%I[ ]	Interpolated symbol array (Ruby 2+)
%q[ ]	Non-interpolated String (except for \\ \[ and \])
%Q[ ]	Interpolated String (default)
%r[ ]	Interpolated Regexp (flags can appear after the closing delimiter)
%s[ ]	Non-interpolated Symbol
%w[ ]	Non-interpolated Array of words, separated by whitespace
%W[ ]	Interpolated Array of words, separated by whitespace
%x[ ]	Interpolated shell command