$//$ Function with Arithmetic Expression

function main returns integer;

begin

$7+2*(5+4)$;

end;

How to I modify the grammar below to parse the arithmetic expression above?

It current throws a syntax error, unexpected IDENTIFIER, expecting RETURNS.

$\%\}$

$\%$define parse.error verbose

$\%$token IDENTIFIER INT$\_$LITERAL CHAR$\_$LITERAL REAL$\_$LITERAL

$\%$token ADDOP MULOP ANDOP RELOP ARROW OROP NOTOP REMOP EXPOP NEGOP

$\%$token BEGIN$\_$ CASE CHARACTER ELSE END ENDSWITCH FUNCTION INTEGER IS LIST OF OTHERS RETURNS SWITCH WHEN ELSIF ENDFOLD ENDIF FOLD IF LEFT REAL RIGHT THEN

$\%\%$

function:

function$\_$header optional$\_$variable body ;

function$\_$header:

FUNCTION IDENTIFIER RETURNS type $\text{'}$;$\text{'}$ ;

type:

INTEGER $|$

CHARACTER ;

optional$\_$variable:

variable $|$

$\%$empty ;

variable:

IDENTIFIER $\text{'}$:$\text{'}$ type IS statement $\text{'}$;$\text{'}|$

IDENTIFIER $\text{'}$:$\text{'}$ LIST OF type IS list $\text{'}$;$\text{'}$ ;

list:

$\text{'}(\text{'}$ expressions $\text{'})\text{'}$ ;

expressions:

expressions $\text{'},\text{'}$ expression$|$

expression ;

body:

BEGIN$\_$ statement$\_$ END $\text{'}$;$\text{'}$ ;

statement$\_$:

statement $\text{'}$;$\text{'}|$

error $\text{'}$;$\text{'}$ ;

statement:

expression $|$

WHEN condition $\text{'},\text{'}$ expression $\text{'}$:$\text{'}$ expression $|$

SWITCH expression IS cases OTHERS ARROW statement $\text{'}$;$\text{'}$ ENDSWITCH ;

cases:

cases case $|$

$\%$empty ;

case:

CASE INT$\_$LITERAL ARROW statement $\text{'}$;$\text{'}$ ;

condition:

condition ANDOP relation $|$

relation ;

relation:

$\text{'}(\text{'}$ condition $\text{'})\text{'}|$

expression RELOP expression ;

expression:

expression ADDOP term $|$

term ;

term:

term MULOP primary $|$

primary ;

primary:

$\text{'}(\text{'}$ expression $\text{'})\text{'}|$

INT$\_$LITERAL $|$

CHAR$\_$LITERAL $|$

IDENTIFIER $\text{'}(\text{'}$ expression $\text{'})\text{'}|$

IDENTIFIER ;

$\%\%$

void yyerror$($const char$*$ message$)\{$

appendError$($SYNTAX$,$ message$)$;

$\}$

int main$($int argc, char $*$argv$[])\{$

firstLine$()$;

yyparse$()$;

lastLine$()$;

return $0$;

$\}$