This function is called to analyze a sub-expression that has no lower precedence operators than i (unless enclosed in parentheses inside the sub expression).
If the argument variable i is 1 then this function simply calls @xref{ex_Tag}. Otherwise it calls itself recursively twice with optionally compiling the operator between the two subexpressions.
peNODE ex_Expression_i(peXobject pEx,
int i
){
The function returns pointer to the new node.