Your confusion is due to the fact that the class method module constants hides the instance method module constants for module.
Ruby define constant in class.
Module constants all constants one argument.
A class in ruby always starts with the keyword class followed by the name of the class.
Classes become more useful when you start adding instance methods instance variables to them.
Note that constants do not exist until a value is actually assigned to them.
You can squeeze an orange to get juice.
Ruby performs a lookup for the constant that follows a class or module keyword because it needs to know if the class or module is going to be created or reopened.
The class customer can be displayed as class customer end you terminate a class by using the keyword end.
All the data members in the class are between the class definition and the end keyword.
So this is the way ruby s constant lookup algorithm works.
Ruby class and module names are also constants but they are conventionally written using initial capital letters and camel case likethis.
Module constants true constants of module and.
6 1 reloading and stale objects.
The name should always be in initial capitals.
If the constant is not defined at that point it is not considered to be a missing constant autoloading is not triggered.
Same class method as in 1 8.
Class orange def squeeze puts here s your juice end end orange orange new orange squeeze.
6 1 1 constants after the class and module keywords.
When we call sub class instance foo via constant ruby searches for foo constant in myclass and its superclasses.
Usr bin ruby class example var1 100 var2 200 def show puts value of first constant is var1 puts value of second constant is var2 end end create objects object example new object show here var1 and var2 are constants.
It never looks in subclass and so it can t find a definition for the constant.
It is very important to understand that ruby does not have a way to truly reload classes and modules in memory and have that reflected everywhere they are already used.
Here s a code example.
Although constants should not be changed you can modify the internal states of the objects they reference as seen in.
This will produce the following result.
In ruby 1 9 this has been addressed by adding an optional parameter.
A method is a thing your class can do.
Uses the instance method.
