ESPL1000 uses
struct to define a Composite Data Type.
ESPL1000 structs like C structs semantically, but different
syntactically.
ESPL1000 uses ';' at the end of each struct member
declaration, same as in C, because this notation is both simple on it's own
and also familiar to those who know C.
struct MyStruct {
int a;
MyStruct b;
}