Compilers: Principles and Practice by Pearson

Syntax-directed Translation 143

better. We shall discuss Implicit Stacking in an RDP, Synchronized Semantic Stacks and Action

Symbols.

5.1 Implicit Stacking in RDP

If the language can be parsed by an RDP, then a simple method is available to implement many of

the semantic analysis operations. The method illustrated here is further used extensively in Chapter 8

on Intermediate Code, for generating the Intermediate representation of the program. Several further

examples of implicit stacking in RDP are given.

We shall use the following sub-grammar of an IF-THEN-ELSE construct:

if-stmt : IF logic-expr THEN stmt-list FI

| IF logic-expr THEN stmt-list1 ...