Erlang: the power of functional programming

Functional programming in Erlang, including streams, lazy evaluation and dependent types.

Code for the presentation at Erlang/Elixir Factory, Buenos Aires, 2017 and CODE BEAM SF 2018. Slides in EFBA.pdf and CBSF.pdf.

Notes on different approaches

lazy.erl Definitive version of lazy examples in which references stored in a named ETS table. References are allocated sequentially, with value at key 0 being the current index used.

lazy0.erl Version in which the id of a table is passed explicitly into all functions that might use it.

lazy2.erl Incomplete experiment in which use a hashed version of an expression as its address in an ETS table. Unsuccessful: hasing appears to be too eager to work.

lazy3.erl Definitive version of lazy examples which doesn't use ETS tables or other side-effecting constructs. References are stored in a map, and allocated sequentially, with value at key 0 being the current index used. The map is threaded through the computation.

memo.erl Two experiments in memoisation: using ETS and in the data.

rps.erl Rock-Paper-Scissors, a basic implementation in Erlang.

maze.erl List of routes through a maze: a good candidate for making lazy: want to try it?

stream.erl Demand-driven evaluation for streams: first iteration with no attempt to optimise.