coffeescript class variable scope

csscope.coffee

class myclass
  local_var=[]
  local_func = ->
     local_var+=1 

  local_func_wrong = ->
    @myclass.class_var++  # wrong! no way to access class var
    @inst_var++         # wrong! no way to access instance var


  @class_var:0    # class variable
  @class_func: -> # class function
    local_func()  # you can call local function
    local_var++   # you can access local variable
    @class_var=4  # you can access class variable through @ operator
    

  @class_func_wrong: ->
    inst_var=3 # wrong! you can't access instance variable
    inst_func() # wrong! you can't call instance function
   

  inst_var: 0     # instance variable
  inst_func: ->   # instance function
    @inst_var++   # you can access instance variable through @ operator
    local_func()  # you can call local function
    local_var++   # you can access local variables
    myclass.class_func() # you can call class function via prefixing the classname.
    myclass.class_var++  # you can access class variable via prefixing the classname.

i1 = new myclass()
i2 = new myclass()

i1.inst_var++  # you can access an instance's variable
i2.inst_func()   # you can call an instance's function

i1.class_var++   # wrong! you can't access an instance's class variable 
i1.class_func()    # wrong! you can't call an instance's class function

myclass.class_func()  # you can access a class's function
myclass.class_var++  # you can access a class's variable

i2.local_var++   # wrong! you can't access an instance's class's local var
i2.local_func()  # wrong! you can't call an instance's class's local var

simple rules

• 需要多份的
  • 宣告成 instance var
• 只要一份的
  • 只有class 內部要存取的 -> 宣告成 local var
  • 外部也要能存取 -> 宣告成class var