有趣的程序

1.to_proc

class Array
def to_proc
proc { |receiver| receiver.send *self }
end
end

[ 'Hello', 'Goodbye' ].map &[ :+, ' BeiJing!' ]

#=> ["Hello BeiJing!", "Goodbye BeiJing!"]

2.map(&:key)

order_records = OrderRecord.all(:all, :limit => 10)

order_records.map(&:order_no)

#=> ["20140627141050-5096zG", "20140627143533-90bm9v", "20140627143648-2sJQxR", "20140627161046-UE0y07", "20140627161456-16GGT1", "20140627161707-58Lc3t", "20140627173915-0mI1Ji", "20140627175248-31YTtk", "20140627180802-s487cX", "20140717112957-eQ993g"]

arr = '100+100+200+100'

arr.split('+').map(&:to_i)

3.hash = JSON.parse content.gsub!('=>', ':')

require 'rubygems'
require 'json'

content = %Q({\"credentials\"=>{\"token\"=>\"F538FF45937887AF7246E50928E0961F1\", \"refresh_token\"=>\"6EC400DD7B547B401D29474EA68952145\", \"expires_at\"=>1418310654, \"expires\"=>true}})

hash = JSON.parse content.gsub!('=>', ':')

4.好有创意

5.对 define_method。 instance_variable_get，instance_variable_set 的使用

class Activity
attr_reader :data

def self.<< data
new(data).call
end

def self.data_reader *attrs

attrs.each do |attr|
define_method attr do
instance_variable_get("@#{attr}") || \
instance_variable_set("@#{attr}", data[attr.to_sym])
end
end

end

def self.default attr, default
orig_attr = "#{attr}_without_default"
alias_method orig_attr, attr
define_method attr do
send(orig_attr) || default
end
end

def self.set name, value

if value.is_a?

Symbol
define_method name do
instance_variable_get("@#{name}") || \
instance_variable_set("@#{name}", send(value) )
end
elsif value.respond_to?

:call
define_method name do
instance_variable_get("@#{name}") || \
instance_variable_set("@#{name}", value.call)
end
else
define_method name do
instance_variable_get("@#{name}") || \
instance_variable_set("@#{name}", value)
end
end

end

def initialize(data = {})
@data = data
end

def call
''
end

private
def set(name,value)
instance_variable_set("@#{name}", value)
end

def get_or_set(name)
value = instance_variable_get("@#{name}")
return value if value
value = yield
instance_variable_set("@#{name}", value)
end

end

6. 编辑器