A simple Trie structure implementation in Swift for indexing and searching words.

This library does not include a user interface, it was built to be a simple easy to use auto-completion tool. Originally, it written for MessMoji.

Andrew Crookston

Please send me a tweet if you like this library or have questions or feedback: @acr

The Example project contains a full working implementation of the library including a table view, and an input field to search the SOWPODS word list. If you are looking for an auto-complete solution with a UI, take a look at the Example project.

To run the example project, clone the repo, and run pod install from the Example directory first.

The library was written for iOS. It has no external requirements and it's possible it works on macOS or other Swift platforms, but this has not been tested.

ACRAutoComplete is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "ACRAutoComplete"

First add the protocol to whatever object you wish to index, for example with a Word class, and add the required methods:

import ACRAutoComplete

class Word : Searchable {
    let word : String
    init(_ word: String) {
        self.word = word
    }

    // From Searchable protocol
    func keywords() -> [String] {
        return [word]
    }

    // Hashable
    var hashValue: Int { return word.hashValue }

    static func == (lhs: Word, rhs: Word) -> Bool {
        return lhs.id == rhs.id
    }
}

In your controller or place where you wish to use the index. Create an `AutoComplete` object with the `Word` class:
```swift
let autocomplete = AutoComplete<Word>()

Insert the objects you wish to index:

let football = Word("Football")
autocomplete.insert(football)

Finally, when needed, search the index for any matching objects:

autocomplete.search("foot") // -> [Word("Football")]

For testing, the SOWPODS word list has been used. It contains 267753 words which takes roughly 5 seconds to index in the iOS Simulator. Searching is very quick and will take less than 200ms, depeding .

ACRAutoComplete is available under the MIT license. See the LICENSE file for more info.

The example project (not the Pod) includes a SOWPODS word file which is used for testing. The license of the SOWPODS file when downloaded was unknown but was labeled "open source".