It's been around for a long time, but everyone's talking about it all of a sudden. But why and why now? We've been

programming in languages like Java for a while, quite well. Now we're asked to change and the languages themselves

are changing towards this style of programming. In this keynote, a passionate polyglot programmer and author of

"Functional Programming in Java: Harnessing the Power of Java 8 Lambda Expressions" will share the reasons

we need to make the paradigm shift and the pure joy—the benefits—we will reap from it.

In this talk, we'll explore why some technologies end up inexplicably dominating our field while others fade away despite their obvious merits. What will it take for the languages we care about to succeed, and what are the consequences of success? Let's apply a broad perspective to the mess we've made of modern computer science, and explore our options for getting the situation back on track through a careful examination of history, science and ponies.

Code used during the talk: https://github.com/shashi/fuconf-talk
Slides: https://docs.google.com/presentation/d/16Xfqd-xU8y2JEN0TIcacDoYnp0b5-W7ESDB5v1SmcXs/edit#slide=id.p

Elm is a strongly typed functional reactive programming (FRP) language that compiles to HTML, CSS, and Javascript. In Elm, the Signal type represents a time-varying value--things like mouse position, keys pressed, current time are signals. With Signals, one can write terse code that is isomorphic to a dataflow diagram of the app. The code hence feels natural and is 100% callback free. All this, with powerful type inference.

This talk is an introduction to FRP. It explores functionally composing graphics and UIs, and creating interactions and animations with the Signal type. There will also be an overview of Elm’s execution mechanism and the time traveling debugger: a consequence of Elm's purely functional approach.

While instructive, it will be good fun too, in the spirit of Elm.

Most applications running in the cloud are not optimized to do so. They make assumptions about the underlying operating system, resulting in larger footprints with increased costs and risks.  The open source Mirage OS represents a new approach where the application code is combined with the specific components of the operating system it needs into a single-purpose unikernel appliance. With Mirage OS, developers can create lean and efficient unikernels for secure, cost-effective and high-performance network applications. Mirage OS unikernels run directly on the Xen Project hypervisor, which allows them to be quickly deployed to many leading cloud platforms.

Mirage OS is fully written in OCaml, from the device drivers and network stack to higher-level synchronisation protocols and databases. In this presentation I will explain how we developed Mirage OS and why we choose to do so in a strongly typed functional language with a powerful module langage. I will then present some of the new features of Mirage OS v2.0 such as: support for ARM devices, Irmin: a Git-like distributed database and OCaml-TLS: a comprehensive implementation of the TLS protocol in pure OCaml. 

APL is a member of the family of languages that are approaching middle age (Ken Iverson’s book titled “A Programming Language” was published in 1962). APL was very influential in the 60’s and 70’s, and widely used to deliver “end user computing” - but although the REPL, dynamic scope and lack of a type system endeared APL to domain experts, it also drew fire from computer scientists, most famously when Edsger Dijkstra declared that “APL is a mistake, carried through to perfection. It is the language of the future for the programming techniques of the past it creates a new generation of coding bums.”

Dyalog is a modern, array-first, multi-paradigm programming language, which supports functional, object-oriented and imperative programming based on an APL language kernel. Dyalog allows people with good ideas – from bright high school students to PhDs – to contribute directly to the software development process using a notation which fits comfortably with those used in their own domains. Subject matter experts can write prototypes or, with suitable training and/or support, highly efficient, parallel and robust code that can be embedded in high-performance production applications.

There is a growing need for scalable, realtime business systems that are continuously running and highly-available. Two very different frameworks/approaches you could use to build such systems are Storm and Akka.

Systems created with Storm or Akka are distributed, at runtime, on as many machines as you choose. The inherent concurrency implied by this brings the issues of State, Time and Failure into sharp focus. Functional programming has much to say about dealing with state and time; not surprisingly, both Storm and Akka have strong roots in functional languages (for Storm it is Clojure, and for Akka, Scala).

In this talk we'll explore the core concepts and challenges of distributed computation; the role of functional programming in concurrent distributed computing; we'll take a look at Storm and Akka, by example, and see that as different as these 2 approaches are, the underlying difficulties of distributed computation remains evident in both: dealing with time, and dealing with failure.

Sync, Async, Blocking, Non-Blocking, Streaming are the buzzwords in the reactive programming world. This talk will attempt to attach some meaning to them. It will also demo the performance and resource consumption patterns for blocking-io, Scala Futures and RxJava Observables for comparable programs. Finally, a command line application that consumes twitter streams API will demo what is possible using the new reactive abstractions.

Traditionally functions return some value. Someone is waiting for that value and does some computation with it. This "someone" is called the continuation of this value. In a normal functional call, the continuation is "implicit". In the "continuation passing style" (hence forth called with the short form, CPS), we make the continuations explicit. In this style, function definitions take an extra argument called "continuation" and it never return. The "return value" of the function 'continues' by passing this value as an argument to the continuation. Continuations are sometimes called "gotos with arguments".

CPS is used as an intermediate stage while compiling a program since it makes the control structure of the program explicit and hence can be converted easily to machine code. Another feature of a CPS-transformed function is that it is tail-recursive even if the original function was not written in a tail-recursive style.

Continuations enable a programmer to build new control operators (if the language's built-in operators does not already provide the control operators the programmer need).

Javascript programmers have had a lot of choices when it comes to programming. There were days of mootools, scriptaculous and jQuery and then there are now days of Angular, Ember, Knockout and the like. As a javascript programmer myself, I find that Clojurescript/React as Om offers a fresh perspective into building performant Javascript UIs that are easy to write.

The talk will introduced concepts of React, immutable datastructures in Clojure and live code an application that demonstrates the concepts.

Brief history of recursion 

Snippets from a few languages

What is tail recursion?

Design choices around recursion

The importance of tail recursion in erlang

How do you profile such improvements?

I learn different languages not to make use of them, but to program in my current languages in a better way. As we adapt functional style of programming in mainstream languages, like Java, C#, and C++, we can learn a great deal from a language that is touted as a purely functional language.

Haskell is statically typed, but not in a way like Java, C#, or C++. Its static typing does not get in the way of productivity. Haskell quietly does lazy evaluation and enforces functional purity for greater good. Everyday programmers, like your humble speaker, who predominantly code in mainstream languages, can greatly benefit from learning the idioms and style of this elegant language. The next time we sit down to crank out some code in just about any language, we can make use of some of those styles, within the confines of the languages, and move towards a better, functional style.

Functional programming as a programming style and discipline is useful even in languages which are not pure functional languages. By practising programming in a pure functional language like Haskell, programmers can drastically improve the quality of code when coding in other languages as well.

The talk is based on first hand experience of using Haskell in internal courses in our organisation to improve code quality.

This talk will cover Gofer (one of the earliest variants of Haskell) as a teaching tool, including the choice of the language, the features from Haskell that should (and shouldn't) be covered and the obstacles and benefits of the exercise.

Elixir is a functional and dynamic language built on top of the Erlang VM. The development of the language is happening at a fast pace. People in the community have participated actively to write tools and libraries, required to write real-world apps in Eilxir.

In this talk, I will attempt to skim through all the new features in Elixir, a few important libraries with short examples and some learning resources.

Each tool showcased in this talk, will have a 3-step tryout, with the simplest example.

As Java programmers we have used a number of design patterns and design techniques. With the introduction of lambda expressions, we now have some more sharper tools in our design toolbox. Come to this presentation to learn how we can implement some elegant design ideas with lambda expressions. We will learn about these design techniques, not using diagrams, but by realizing the ideas in code.

The programming paradigms that served us so well through the 80s and 90s are failing us. Building systems the way we're used to building them always seems to end in the inevitable death march towards exponential complexity. But once you stop to ask the right question- "what's really causing all this complexity?" - you realise the answers have really been staring you in the face all along. Debugging is only hard when you can't reason about your code. Concurrency is only hard when you can't predict the state of your code. Reusability is only hard when your components aren't naturally composable.

Fortunately, languages addressing these issues specifically are popping up all over the place. In many cases, it turns out we've had the solutions to our problems for a long time, we've just forgotten about them, or never really bothered to look. Let's take a moment to explore some of these languages, not as exercises in syntactic details, but looking at the inherent properties in their design that enable us to defy decades of OO tradition and write honest-to-Dijkstra bug free, fault tolerant software without even trying. After half a century in the wilderness, functional programming seems to finally be gaining some ground on the barbarians. Let's examine why.