smart-hash 0.1.2

partial queries in HashSets, the traits.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

use std::collections::HashSet;

pub trait SmartHash { 
    type option;

    fn into_option(&self) -> Self::option;
}

pub trait SmartHashOpt where Self : Default { }

pub trait SmartHashSet where <Self as SmartHashSet>::output : SmartHash, <Self as SmartHashSet>::option : Default
{
    type output;
    type option;

    fn get_matching<'a>(&'a self, options : <<Self as SmartHashSet>::output as SmartHash>::option) -> Option<Vec<&'a Self::output>>;

    fn get_none_default(&self) -> Self::option {
        Self::option::default()
    }
}

impl<SH> SmartHashSet for HashSet<SH>
    where SH : SmartHash + std::hash::Hash + std::cmp::Eq,
            <SH as SmartHash>::option : std::cmp::PartialEq + Default,
{ 
    type output = SH;
    type option = SH::option;

    fn get_matching<'a>(&'a self, options : <SH as SmartHash>::option) -> Option<Vec<&'a SH>> {
        let mut matches : Vec<&SH> = Vec::new();

        for item in self.iter() {
            let option = item.into_option();
            if option == options {
                matches.push(&item);
            }
        }

        if matches.len() > 0 {
            Some(matches)
        } else {
            None
        }
    }
}