feature/safe-constructors-and-exception-handling
During construction of an object not all state is consistent, so not all functions can be called in a safe way. During exception handling, in case of bad resource initialization, not all resources are initializated correctly. Hence, the compiler should check the usage of functions at compile-time, and at run-time it must take trace of initializated resources, and manage code accordingly.
TODO check how CLOS solve this problem