12.3 MiniC Grammar for yacc

%union {
Symbol *sym; /* symbol table pointer */
Symbol *inst; /* machine instruction */
int narg; /* number of arguments */
}
%token <sym>NUMBER STRING PRINT BLTIN UNDEF WHILE FOR IF ELSE
%token <sym>FUNCTION PROCEDURE RETURN FUNC PROC READ INT VAR IVAR SVAR END
%token <narg>ARG
%type  <sym>  expr
%type <inst> stmt asgn prlist stmtlist
%type <inst>cond while for if begin end
%type <sym>procname
%type <narg>arglist
%type  <sym>  dtype
%type  <sym>  dlist
%right ‘=’ ADDEQ SUBEQ MULEQ DIVEQ MODEQ
%left OR
%left AND
%left GT GE LT LE EQ NE
%left ‘+’ ‘–’
%left ‘*’ ‘/’ ‘%’
%left UNARYMINUS NOT INC DEC
%right ‘^’
%%
list:  stmtlist END
       | stmtlist error END
;
asgn:  VAR ‘=’ expr
       | IVAR ‘=’ expr
| IVAR ADDEQ expr
| IVAR SUBEQ expr
| IVAR MULEQ expr
| IVAR DIVEQ expr
| IVAR MODEQ expr
| ARG ‘=’ expr { }
| ARG ADDEQ expr { }
| ARG SUBEQ expr { }
| ARG MULEQ expr { }
| ARG DIVEQ expr { }
| ARG MODEQ expr { }
;
stmt:  decl
       | defn
       | expr
| RETURN
| RETURN expr
| PRINT prlist
| while’(’ cond ‘)’ stmt end
| for’(’ cond ‘;’ cond ‘;’ cond ‘)’ stmt end
| if’(’ cond ‘)’ stmt end
| if’(’ cond ‘)’ stmt end ELSE stmt end
| ‘{’ stmtlist ‘}’
;
cond:  expr
;
while: WHILE
;
for:  FOR
;
if:  IF
;
begin:  /* nothing */
;
end:  /* nothing */
;
stmtlist: /* nothing */ }
| stmtlist ‘
’
| stmtlist stmt
;
expr:  INT
       | NUMBER
| VAR
| IVAR
| ARG
| asgn
| FUNCTION begin ‘(’ arglist ‘)’
| READ ‘(’ VAR ‘)’
| BLTIN ‘(’ expr ‘)’
| ‘(’ expr ‘)’
| expr ‘+’ expr
| expr ‘–’ expr
| expr ‘*’ expr
| expr ‘/’ expr
| expr ‘%’ expr
| expr ‘^’ expr
| ‘–’ expr %prec UNARYMINUS
| expr GT expr
| expr GE expr
| expr LT expr
| expr LE expr
| expr EQ expr
| expr NE expr
| expr AND expr
| expr OR expr
| NOT expr
| INC VAR
| DEC VAR
| VAR INC
| VAR DEC
;
prlist:  expr
| STRING
| prlist ‘,’ expr
| prlist ‘,’ STRING
;
defn:  FUNC procname ‘(’ ‘)’ stmt
;
procname: VAR
| FUNCTION
;
arglist:  /* nothing */
| expr
| arglist ‘,’ expr
;
decl:    dtype ‘:’ dlist
       ;
dtype:   IVAR
       | VAR
       | SVAR
       ;
dlist:   VAR
       | dlist ‘,’ VAR
       ;
%%
/*  end of grammar */