Indicium

A simple search engine for collections and key-value stores with typeahead/autocomplete.

Quick Guide

For our Quick Guide example, we will be searching inside of the following struct:

struct MyStruct {
    title: String,
    description: String,
}

Implementing Indexable

To begin we must make our struct indexable. We do this by implementing the Indexable trait for our struct:

use indicium::simple::Indexable;

impl Indexable for MyStruct {
    fn strings(&self) -> Vec<String> {
        vec![
            self.title.clone(),
            self.description.clone(),
        ]
    }
}

The idea is to return a String for every field that we would like to be indexed. Once this trait is implemented, the struct can be indexed by indicium.

Don't forget: you may make numbers, numeric identifiers, enums, and other types indexable by converting them to a String and including them in the returned Vec<String>!

Indexing a Collection

To index an existing collection, we can iterate over the collection. For each record, insert it into the index. This might look like something like these two examples:

let mut search_index: SearchIndex<usize> = SearchIndex::default();

my_vec
    .iter()
    .enumerate()
    .for_each(|(index, element)| search_index.insert(&index, element));

let mut search_index: SearchIndex<usize> = SearchIndex::default();

my_hashmap
    .iter()
    .for_each(|(key, value)| search_index.insert(&key, value));

The above examples will work for a previously populated Vec or HashMap. However, the preferred method is to index your collection (Vec, HashMap, etc.) as it is being populated.

Search

Once the index has been populated, you can use the autocomplete and search functions.

The autocomplete function will autocomplete / typeahead the last keyword in the string. This function will return several strings with different options for the autocompleting the last keyword. The results are returned in lexographic order:

let keywords: Vec<String> = search_index.autocomplete(&"ass".to_string());

assert_eq!(keywords, vec!["assassin", "assistance"]);

The search function will return all keys for indexed structs that exactly match the single String keyword provided by the caller:

let indicies: Vec<u32> = search_index.search_keyword(&"Helicopter".to_string());

assert_eq!(indicies, Some(vec![&1]));

Note: the autocomplete_keyword and search_keyword functions work on strings that are expected to contain only a single keyword. For small collections, this might be a workable & lighter-weight solution than using their big brothers.

The autocomplete_keyword function will return all indexed keywords that begin with the single String provided by the caller:

let keywords: Vec<String> = search_index.autocomplete_keyword(&"ass".to_string());

assert_eq!(keywords, vec!["assassin", "assistance"]);

The search_keyword function will return all keys for indexed structs that exactly match the single String keyword provided by the caller:

let indicies: Vec<u32> = search_index.search_keyword(&"Helicopter".to_string());

assert_eq!(indicies, Some(vec![&1]));