13. A system comprising: a memory; and a processing device coupled with the memory to execute an interpreted language software application to execute an expression in the interpreted language software application to evaluate an object of a first class that comprises one or more objects and an object of a second class, the second class being a concise expression class, execute the expression in the interpreted language software application to determine whether data associated with the object of the first class exists, return a result of the execution of the expression when data associated with the object of the first class exists within the software application, and return an instance of an object of the concise expression class when data associated with the object of the first class does not exist within the interpreted language software application, wherein when the concise expression class comprises an attribute of the object of the second class, an attribute of the returned instance of the object of the concise expression class corresponds to the attribute of the object of the second class.
13. A system comprising: a memory; and a processing device coupled with the memory to execute an interpreted language software application to execute an expression in the interpreted language software application to evaluate an object of a first class that comprises one or more objects and an object of a second class, the second class being a concise expression class, execute the expression in the interpreted language software application to determine whether data associated with the object of the first class exists, return a result of the execution of the expression when data associated with the object of the first class exists within the software application, and return an instance of an object of the concise expression class when data associated with the object of the first class does not exist within the interpreted language software application, wherein when the concise expression class comprises an attribute of the object of the second class, an attribute of the returned instance of the object of the concise expression class corresponds to the attribute of the object of the second class. 18. The system of claim 13 , wherein when the processing device executes the expression to evaluate the object of the second class, the processing device to access data in an object outside of the second class.