ifyouseewendy’s gists

ifyouseewendy / constant_reference.rb

Created October 13, 2014 05:37

	##
	# Note from Ruby Pocket Reference
	#
	# Since constants refer to objects, the contents of the object
	# to which the constant refers may change without Ruby generating
	# a warning. Thus, Ruby constants are called mutable, because,
	# although the constant is only expected to refer to a single
	# object throughout the program, what's contained in that object
	# may vary.

ifyouseewendy / method_visibility_in_mixined_module.rb

Created October 13, 2014 05:12

Check the visibility of private and protected mixined from module. Example from http://www.treibstofff.de/2009/08/07/ruby-visibility-of-private-and-protected-module-methods-when-mixed-into-a-class/

ifyouseewendy / subclasses_of.rb

Created October 8, 2014 14:19

Get subclasses, using Iterator Pattern

	def subclasses_of(superclass)
	subclasses = []

	ObjectSpace.each_object(Class) do \|k\|
	next if !k.ancestors.include?(superclass) \|\| superclass == k \|\| k.to_s.include?('::') \|\| subclasses.include?(k.to_s)
	subclasses << k.to_s
	end

	subclasses
	end

ifyouseewendy / metal_and_base.md

Last active August 29, 2015 14:06

How to make method in module override the method in base class?

module A
  def foo
    puts 'foo from A'
    super
  end
end

module B
 def foo

ifyouseewendy / git-fu.md

Last active August 29, 2015 14:06

some useful commands

How to revert all the commits involved by a merge?

git revert {merge SHA} -m 1

ref -m, --mainline <n> parent number

eg.

➜  wendi-mac ~/tmp/demo (master)                                                                   (ruby-2.0.0-p353)

ifyouseewendy / config.auth.ru

Created September 23, 2014 08:05

a bundle of `config.ru`, testing rack middlewares.

	use Rack::Auth::Basic, 'app' do \|usr, pwd\|
	usr == 'wendi' && pwd == '123123'
	end

	# => Request Headers
	# Authorization:Basic d2VuZGk6MTIzMTIz

	# realm = 'Hello, wrold'
	# opaque = '1234567890'
	# use Rack::Auth::Digest::MD5, realm, opaque do \|password\|

ifyouseewendy / mongo-dump_and_restore.rb

Created May 23, 2014 02:47

A basic script to integrate `mongodump` and `mongorestore`.

ifyouseewendy / throw_and_catch.rb

Created May 19, 2014 16:08

throw and catch example

	# catch executes its block.
	# If a throw is executed, Ruby searches up its stack for a catch block with a tag corresponding to the throw's tag.
	# If found, that block is terminated, and catch returns the value given to throw.
	# If throw is not called, the block terminates normally, and the value of catch is the value of the last expression evaluated.
	# catch expressions may be nested, and the throw call need not be in lexical scope.

	def routine(n)
	puts n
	throw :done, "I'm the return value" if n <= 0
	routine(n-1)

ifyouseewendy / enumerator-lazy-benchmark.rb

Created May 16, 2014 11:03

Does Enumerator::Lazy make loops running faster? Maybe, It depends.

	# ruby 2.1.2

	require 'benchmark/ips'

	Benchmark.ips do \|x\|
	x.report { (1..100).select { \|x\| x % 3 == 0 }.select { \|x\| x % 4 == 0 } }
	x.report { (1..100).select { \|x\| x % 3 == 0 && x % 4 == 0 } }
	x.report { (1..100).lazy.select { \|x\| x % 3 == 0 }.select { \|x\| x % 4 == 0 }.to_a }
	end

ifyouseewendy / proc-curry.rb

Created May 16, 2014 09:19

a Proc#curry note from http://www.sitepoint.com/functional-programming-techniques-with-ruby-part-ii/

	# http://ruby-doc.org/core-2.0/Proc.html#method-i-curry
	#
	# curry → a_proc
	#
	# Returns a curried proc.
	#
	# curry(arity) → a_proc
	#
	# If the optional arity argument is given, it determines the number of arguments.
	#

	# ruby 2.1.2

	require 'benchmark/ips'

	Benchmark.ips do \|x\|
	x.report { (1..100).select { \|x\| x % 3 == 0 }.select { \|x\| x % 4 == 0 } }
	x.report { (1..100).select { \|x\| x % 3 == 0 && x % 4 == 0 } }
	x.report { (1..100).lazy.select { \|x\| x % 3 == 0 }.select { \|x\| x % 4 == 0 }.to_a }
	end