export class Extractor<O> {
    private extract: (text: string) => O | null;

    public constructor(extract: (text: string) => O | null) {
        this.extract = extract;
    }

    public get(text: string) {
        return this.extract(text);
    }

    public or<T>(other: Extractor<T>) {
        const this_extract = this.extract;
        return new Extractor(text => {
            const r1 = this_extract(text);
            if (r1 !== null) return r1;
            else return other.extract(text);
        });
    }
}