In another tutorial, I showed a concept definition for Yellkey, a popular URL shortening service: concept Yellkey purpose shorten URLs to common words principle if you register a URL u for t seconds and obtaining a shortening s, looking up s will yield u until the shortening expires t seconds from now state used: set String shortFor: used -> one URL expiry: used -> one Date const shorthands: set String actions // register URL u for t seconds // resulting in shortening s register (u: URL, t: i...
