/** execute_FOR Executes for statement.
* initialize condition increment
* for(<statement>; <expression>; <expression>)
* <statement>;
*
* @param p_function_id
*/
void cx_executor::execute_FOR(cx_symtab_node * p_function_id) {
bool condition = false;
get_token(); // for
// get the location of where to go to if <expr> is false.
int break_point = get_location_marker();
get_token();
int statement_location = get_location_marker();
get_token();
int condition_marker = get_location_marker();
get_token();
int increment_marker = get_location_marker();
get_token();
// (
get_token();
if (token != tc_semicolon) {
// declaration would go here //
execute_assignment(p_node);
}
do {
get_token(); // ;
if (token != tc_semicolon) {
// expr 2
execute_expression();
get_token(); // ;
} else get_token();
condition = top()->basic_types.bool__;
pop();
if (condition) {
go_to(statement_location);
get_token();
execute_statement(p_function_id);
if (break_loop) go_to(break_point);
} else {
go_to(break_point);
get_token();
break;
}
go_to(increment_marker);
get_token();
// expr 3
execute_expression();
go_to(condition_marker);
} while (current_location() == condition_marker);
break_loop = false;
}
/** execute_statement Execute a Cx statement
*
* @param p_function_id : ptr to the routine symtab node
*/
void cx_executor::execute_statement(cx_symtab_node *p_function_id) {
if (token != tc_left_bracket) {
++statement_count;
trace_statement();
}
switch (token) {
case tc_identifier:
{
if (p_node->defn.how == dc_function) {
execute_function_call(p_node);
} else {
cx_symtab_node *p_var = p_node;
get_token();
if (token_in(token, tokenlist_assign_ops)) {
execute_assignment(p_var);
} else {
execute_variable(p_var, false);
pop();
}
}
}
break;
case tc_DO: execute_DO(p_function_id);
break;
case tc_WHILE: execute_WHILE(p_function_id);
break;
case tc_IF: execute_IF(p_function_id);
break;
case tc_FOR: execute_FOR(p_function_id);
break;
case tc_SWITCH: //parse_SWITCH();
break;
case tc_CASE:
case tc_DEFAULT://parse_case_label();
break;
case tc_BREAK:
get_token();
break_loop = true;
break;
case tc_left_bracket: execute_compound(p_function_id);
break;
case tc_RETURN: execute_RETURN(p_function_id);
break;
default:
break;
}
}
/** execute_RETURN Assign a return value to the functions StackItem and
* set current location to the return line of the caller.
*
* return;
* return <expression>;
*
* @param p_function_id : ptr to the subroutine name's symtab node
*/
void cx_executor::execute_RETURN (cx_symtab_node * p_function_id) {
execute_assignment(p_function_id);
token = tc_dummy;
}
