Indicium

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

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. The idea is to return a String for every field that we would like to be indexed. Example:

use indicium::simple::Indexable;

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

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 search 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.

Searching

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

The autocomplete function will provide several autocompletion options for the last keyword in the supplied string. The results are returned in lexographic order. Example usage:

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

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

The search function will return the keys for found records. The results are returned in order of descending relevance. Each resulting key can then be used to retrieve the corresponding record from its collection. Example usage:

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

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

The Keyword Methods

The autocomplete_keyword and search_keyword methods work on strings that are expected to contain only a single keyword. For small collections this might be a workable & lighter-weight alternative to using their big brothers.

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

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. Each resulting key can then be used to retrieve the corresponding record from its collection. Example usage: