Instance variables can be referenced in any method of that class.
Ruby instance variable in module.
They are things that hold methods just like classes do.
All methods of a class use the same instance variable table as opposed to local variables where each method will have a different variable table.
Btw you can get a list of instance variables.
Instance variables in views.
For example using instance variables in the controllers helpers and views.
However modules can not be instantiated.
When this module is included in another ruby calls append features in this module passing it the receiving module in mod.
It now makes sense to introduce another language feature in ruby.
For a mixin this means that the module that you mix into your client class the mixee may create instance variables in the client object and may use attr and friends to define accessors for.
To embed a module in a class you use the include statement in the class syntax include modulename if a module is defined in a separate file then it is required to include that file using require statement before embedding module in a class.
In ruby modules are somewhat similar to classes.
The constant variables can not reassign their values.
Rails somehow encourages people using modules and instance variables everywhere.
Remember how instance variables work in ruby.
You can embed a module in a class.
Instance variables begin with commat.
The first mention of an prefixed variable creates the instance variable in the current object self.
Uninitialized instance variables have the value nil and produce warnings with the w option.
Instance variables don t have to be created in the initialize method but that s how you give them an initial value.
I e it is not possible to create objects from a module.
Modules with instance variables could be considered harmful background.
Constant variables start with the upper case letter.
Constants defined inside the class can be accessed inside the class and those defined inside the modules can be accessed inside the modules we can also define the constant as the global which outside the class and module and will be available for all.
Consider the following module.
There are advanced ways to access instance variables like instance variable get but you should avoid these.
Instance variables live within a class instance so as long as that instance stays alive so will the instance variables.
