Chapter 4, Problem 26E

Explanation of Solution

Justification:

• The key idea is to include an indication of scope (referencing environment) in each node of the tree.
• For a language with static scope, the symbol table might consist of a “scope tree” and a mapping from “(id, scope_num)” pairs to type and other information.
• Each “symtab” attribute in the AST would be a pointer to a node of the symbol table scope tree.
• A lookup “((name, t) ϵ symtab)” operation would walk the path from the current scope node to the root of the scope tree...