Compilers: Principles and Practice by Pearson

Intermediate Code 229

a C compiler, which then outputs finished object or machine code, we restrict ourselves to more

traditional intermediate codes.

We now discuss several possible Intermediate forms of the program. We also indicate how to

generate the intermediate code for some of them. For that purpose we use the following example

grammar, given in yacc input format.

program : ’P’ stmt-list ’.’ ;

stmt-list : stmt

| stmt ’;’ stmt-list ;

stmt : expr | if | while | let ;

if : ’I’ ’(’ expr ’)’ stmt-list ’E’

| ’I’ ’(’ expr ’)’ stmt-list ’:’ stmt-list ’E’;

while : ’W’ ’(’ expr ’)’ stmt-list ’Z’ ;

let : ’L’ ’a’ ’=’ expr ;

expr : term | term ’+’ expr ; ...