(types 2)
PostgreSQL
Object Relational DataBase Management System

型の拡張(2)
入力関数（外部表現のためのパーサ）
complex_in
Complex *complex_in(char *str)
{
    double x, y;
    Complex *result;
    if (sscanf(str, " ( %lf , %lf )", &x, &y) != 2) {
        elog(WARN, "complex_in: error in parsing
        return NULL;
    }
    result = (Complex *)palloc(sizeof(Complex));
    result->x = x;
    result->y = y;
    return (result);
}