// mult_expr
// mult_expr [+-] add_expr_list
//
int64_t add_expr()
{
int64_t val;
val = mult_expr();
while (1) {
switch(token) {
case '+': NextToken(); val = val + mult_expr(); break;
case '-': NextToken(); val = val - mult_expr(); break;
default: goto j1;
}
}
j1:
return val;
}
static struct ast_node*
sum_expr(void)
{
struct ast_node *node;
struct ast_node *rest_node;
node = mult_expr();
if (node == NULL)
return NULL;
rest_node = rest_sum(node);
return rest_node;
}
static struct ast_node*
rest_sum(struct ast_node *node)
{
struct ast_node *prev_node;
struct ast_node *ret_node;
struct ast_node *mult_node;
char op;
prev_node = node;
while (TRUE) {
switch(current_token) {
case TOKEN_PLUS:
op = '+';
break;
case TOKEN_MINUS:
op = '-';
break;
default:
goto exit_sum;
}
consume_token();
mult_node = mult_expr();
if (mult_node == NULL) {
error_msg("error: syntax error");
mult_node = (struct ast_node *)ast_node_stub();
}
prev_node = (struct ast_node *)ast_node_op(op, prev_node, mult_node);
}
exit_sum:
ret_node = prev_node;
return ret_node;
}
