Your solution to the previous exercise probably doesn’t generalize to languages with nontrivial scoping rules. Explain how an AG such as that in Figure 4.14 might be modified to use a global symbol table similar to the one described in Section C 3.4.1. Among other things, you should consider nested scopes, the hiding of names in outer scopes, and the requirement (not enforced by the table of Section C 3.4.1) that variables be declared before they are used.

Figure 4.14:

Attributes Class of node Variants Inherited Synthesized location, errors program item int decl, real_decl, read, write, :=, null int.const, real_const, id, +, -, x, , symtab, errors.in location, errors_out xpr symtab location, type, errors, name (id only) float, trunc