theburningmonk

## Functional Track talks from NDC London 2014

### Wednesday 2014-12-3

* [F-Words - Functional Programming Terms With More Than Four Letters - Calvin Bottoms](http://www.ndcvideos.com/#/app/video/2191)
* [Reactive Game Development For The Discerning Hipster - Bodil Stokke](http://www.ndcvideos.com/#/app/video/2221)
* [Erlang Patterns Matching Business Needs -- Torben Hoffman](http://www.ndcvideos.com/#/app/video/2211)
* [Equivalence Classes, xUnit.net, FsCheck, Property-Based Testing -- Mark Seemann](http://www.ndcvideos.com/#/app/video/2291)
* [Functional programming design patterns -- Scott Wlaschin](http://www.ndcvideos.com/#/app/video/2311)
* [Write Your Own Compiler in 24 Hours -- Phillip Trelford](http://www.ndcvideos.com/#/app/video/2281)

theburningmonk

open System

let letters = "acdegilmnoprstuw"
let hash : string -> int64 = Seq.fold (fun acc ch -> acc * 37L + int64 (Seq.findIndex ((=) ch) letters)) 7L
let unhash : int64 -> string =
    Seq.unfold (function 
        | n when n <= 7L -> None 
        | n -> let idx = n % 37L |> int
               (letters.[idx], n / 37L) |> Some)
    >> (fun chars -> new String(chars |> Seq.toArray |> Array.rev))