Class used to store and retrieve expressions.
Motivation: This is a new class not present on the base
C++ implementation. Sinse JavaScript and WebAssembly
don't have good support for destructors/finalizers
at the time of writting this documentation, the Scope
class is used to store a reference to allocated
expressions and can deallocate all resources used by
its expressions at once. If this class wasn't used,
the programmer will have to manually call a function
on each expression to deallocate its resources.