8.11: adda/oop/self's id:
. the expression tree being sent to number's type mgt
contains ptrs to the symbol table nodes;
and, those nodes include type tags .
. the symbol table is constant,
being part of the function's template;
the code points to symbol table nodes,
and then those nodes point to the stack,
or have immediate data if constant .
. how does an object know its own id?
an expression tree sent to a type mgt
has a context (process, act'rec)
that tells it who the caller is,
and all the obj references in the expr'tree
are relative to that context .
. messaging an obj means calling its type mgt,
and then that type mgt is calling the methods
which then have access to the current context
as a global just like in assembly language
where programs have access to a current
stack pointer and program counter .