Summary
In this chapter, you learned about the crucial technical skills and tools used to build symbol tables that track all the variables in all the scopes in the input program. You create a symbol table for every scope in the program and insert entries into the correct symbol table for each variable. All of this is accomplished via traversals of the syntax tree.
You learned how to write tree traversals that create symbol tables for each scope, as well as how to create an inherited attribute for the symbol table associated with the current scope for each node in your syntax tree. You then learned how to insert symbol information into the symbol tables associated with your syntax tree and detect when the same symbol is redeclared illegally. You learned how to write tree traversals that look up information in symbol tables and identify any undeclared variable errors. These skills enabled you to take your first steps in enforcing the semantic rules associated with your programming...