Miles Sabin

One of the distinguishing features of the HList (a data structure which combines the characteristics of both sequences and tuples) implementation in shapeless is its support for a map() higher-order function which, superficially at least, appears to operate very similarly to the one defined on ordinary Scala collection types like List,

To celebrate my talk on shapeless being selected for this year’s Northeast Scala Symposium in Boston, I thought I’d share something entertaining (and slightly whimsical) with you — compile time selection sort at the type-level!

I’ve been selected (against some really excellent competition — it’s a shame more talks couldn’t be squeezed in) to talk at this year’s Northeast Scala Symposium in Boston. Thanks to everyone who voted for my talk about shapeless.

shapeless is an exploration of generic (aka polytypic) programming in Scala derived from the various talks I’ve given over the course of 2011 on implementing scrap your boilerplate and higher rank polymorphism in Scala. It’s published under the Apache 2.0 licence and hosted on github — fork it and have a play.

Functional dependencies are a near-standard extension to Haskell (present in GHC and elsewhere) which allow constraints on the type parameters of type classes to be expressed and then enforced by the compiler. They allow the programmer to state that some of the type parameters of a multi-parameter type class are completely determined by the others.