Add IsValidHabitObj helper trait

This commit is contained in:
Matthias Beyer 2017-11-20 18:59:04 +01:00
parent 6b33fc9e6f
commit 2c655daa39

View file

@ -17,9 +17,14 @@
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
use std::ops::BitXor;
use chrono::NaiveDate;
use error::Result;
use habit::HabitTemplate;
use instance::HabitInstance;
pub const NAIVE_DATE_STRING_FORMAT : &'static str = "%Y-%m-%d";
pub fn date_to_string(ndt: &NaiveDate) -> String {
@ -30,3 +35,18 @@ pub fn date_from_string(s: &str) -> Result<NaiveDate> {
NaiveDate::parse_from_str(s, NAIVE_DATE_STRING_FORMAT).map_err(From::from)
}
/// Helper trait to check whether a object which can be a habit instance and a habit template is
/// actually a valid object, whereas "valid" is defined that it is _either_ an instance or a
/// template (think XOR).
pub trait IsValidHabitObj : HabitInstance + HabitTemplate {
fn is_valid_havit_obj(&self) -> Result<bool> {
self.is_habit_instance().and_then(|b| self.is_habit_template().map(|a| a.bitxor(b)))
}
}
impl<H> IsValidHabitObj for H
where H: HabitInstance + HabitTemplate
{
// Empty
}