This is needed by the pre and post debugging choice and
narrow instructions to see all of the computations
that were created by the choice or narrow instruction.
ModuleLoaderFactory instantiates a ModuleLoader based upon the type of the module file to be loaded (currently one of .class/.txt/.xml)
This class is responsible for
Creating suitable ModuleLoader based upon module filename's extention.
precedence is an int so that one can leave "gaps" in the assigned precedence values
and later when a new operation requires to occupy a position between the gaps it can do so readily.
when PrintAsTxtLoadable visits a symbol,
it creates a textual representation
that can be supplied to the TxtParser and it will load the symbol correctly.
This class contains a collection of Tracing Variables,
a collection of variables that denote the profiling related statistics
and methods to access the statistics.