iOS 11 NLP demo

nlp.swift

let tagger = NSLinguisticTagger(tagSchemes: [.nameType], options: 0)
let dataset: Dataset = .test
let url = Bundle.main.url(forResource: dataset.rawValue, withExtension: "txt")!
let content = try! String(contentsOf: url, encoding: .utf8).components(separatedBy: ["\n"])
var output: [String] = []

/// Map ios nlp tags to canonical tags.
extension NSLinguisticTag {
    var canonical: String {
        switch self {
        case .personalName:
            return "PER"
        case .placeName:
            return "LOC"
        case .organizationName:
            return "ORG"
        default:
            return "O"
        }
    }
}

func iob(_ descr: String, _ prevDescr: String) -> String {
    if descr == "O" {
        return "O"
    }
    if descr == prevDescr {
        return "I-\(descr)"
    } else {
        return "B-\(descr)"
    }
}