All my wtf momements, Ruby or otherwise.

# having a wat moment here in ruby
0 <=> 1
# => -1  (left is less, or another way to think of it, 
# the argument 1 is less than 0)

"0" <=> "1"
# => -1

0 <=> "1"
# => nil

# WAT
# So now if checks will be weird because of nil.  
# This also screws up Comparable <=> methods.  Gah.


# @tpitale:
# Using nil has a hash key {nil => 'value'} #lolwutruby
h = { nil => "wtf" }
# => {nil=>"wtf"}

h.keys.first.nil?
# => true

>> h[nil]
# => "wtf"

# How come Array.collect with a multi-line block returns an Enumerator
# but a single line block returns an array?
puts [1, 2, 3].collect do |number|; number; end
#<Enumerator:0x007fe7d2194fd0>
puts [1, 2, 3].collect {|number| number}.join(",")
1,2,3

# this is just order of operations problems.
puts([1, 2, 3].collect do |number|; number; end.join(","))
1,2,3


# Rubygems can't install all dev dependencies.  Gets in a loop.
# You have to download a gem to hack on and get its dependencies through Bundler.

# $ gem install --include-dependencies --dev bundler -V
# Unable to resolve dependencies: em-spec requires rspec (> 2.6.0), test-unit (>= 0); 
# sdoc-helpers requires sdoc (~> 0.2); railties requires rdoc (~> 3.4); mail requires i18n
# (>= 0.4.0); fuubar requires rspec (~> 2.0); capybara requires rack-test (>= 0.5.4); 
# jeweler requires rdoc (>= 0); uglifier requires execjs (>= 0.3.0); aruba requires rspec 
# (>= 2.7.0); webrat requires rack-test (>= 0.5.3); test-unit-rr requires test-unit (>= 
# 2.1.2); test-unit-notify requires test-unit (>= 2.1.2); mini_shoulda requires minitest (> 
# 2.1.0); actionpack requires i18n (~> 0.5.0), rack (~> 1.2.5), rack-test (~> 0.5.7), erubis 
# (~> 2.6.6); activemodel requires i18n (~> 0.5.0); bourne requires mocha (= 0.10.5); pry 
# requires coderay (~> 1.0.5); eco requires eco-source (>= 0), execjs (>= 0); hoe-highline 
# requires hoe (~> 2.8); coffee-script requires execjs (>= 0); hoe-gemspec requires hoe (>= 
# 2.2.0); hoe-git requires hoe (>= 2.2.0); hoe-bundler requires hoe (>= 2.2.0); gem_hadar 
# requires sdoc (~> 0.2.20)

# if your locale is en_US.UTF-8 (it is)
# and you are using bash and not using zsh 
# you will delete files by accident
# If you are using an older version of bash?  This doesn't seem to happen on bash-3.2 now.
touch resume.txt Trash.me
rm [A-Z]*  # delete all files with a capital letter
ls         # your precious face is deleted


# puts ignores the first newline
puts "this newline is ignored.\n"
puts "two newlines turn into one.\n\n"


# Exceptions have weird corner case
# Raise exception and rescue doesn't work but raise exception and rescue exception does. Wtf.
begin
  raise Exception
rescue
  puts "saved!"  # doesn't fire
end
# => Exception: Exception

begin
  raise Exception
rescue Exception
  puts "this works."
end
# => this works

# even though Exception is at the top of the object hierarchy
# so rescue with no class type should work
begin
  raise StandardError
rescue
  puts "this works."
end

# but did not work with Exception above.


# Ruby base64 generates a hash with a newline which is not allowed in the spec.
# It will be thrown away when you decode it so it's harmless.
# It's harmless unless you are taking the output and using as a hash, index or a search string.
require 'base64'
Base64.encode64("hello")
# => "aGVsbG8=\n"
# The solution is to use strict_encode64
Base64.strict_encode64("hello")
# => "aGVsbG8="
perl -e 'use MIME::Base64; print decode_base64("aGVsbG8=\n") . "\n";'
# => hello
# The new line is thrown away.


# Not ruby but headers in a rails controller isn't a shortcut for request.headers
headers
=> {"X-Frame-Options"=>"SAMEORIGIN", "X-XSS-Protection"=>"1; mode=block", "X-Content-Type-Options"=>"nosniff"}
headers.class
=> Hash

request.headers.class
# => ActionDispatch::Http::Headers

request.headers
#<ActionDispatch::Http::Headers:0x007fe4a5b82e00
 @env=
  {"CONTENT_LENGTH"=>"106",
   "CONTENT_TYPE"=>"application/x-www-form-urlencoded",
   "GATEWAY_INTERFACE"=>"CGI/1.1",
   "PATH_INFO"=>"/bacon",
   "QUERY_STRING"=>"",
   "REMOTE_ADDR"=>"::1",
   "REMOTE_HOST"=>"::1",
   "REQUEST_METHOD"=>"POST",
   ...


# to_i can't be used for number coercion
"5".to_i
# => 5
"golden rings".to_i
# => 0
"5 golden rings".to_i
# => 5

# use Integer(string) instead.

# YAML is terrible.
irb> YAML.load("no: true\nfalse: yes")
# => {false=>true}

Everything Else

What the hell. Using zsh on mac.

$ cd
$ cd sandbox
$ pwd
/var/empty
# What.

Mysql uses sockets if host is localhost. If you say 127.0.0.1, that's different. Because that makes sense.

squarism/wtf_computers.md

All my wtf momements, Ruby or otherwise.

Everything Else