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  • Liked Michael Snoyman
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    Michael Snoyman - Functional Programming for the Long Haul

    45 Mins
    Keynote
    Beginner

    How do you decide whether a programming language is worth using or not? By necessity, such decisions are usually based on assessments that can be made relatively quickly: the ease of using the language, how productive you feel in the first week, and so on. Unfortunately, this tells us very little about the costs involved in continuing to maintain a project past that initial phase. And in reality, the vast majority of time spent on most projects is spent in those later phases.

    I'm going to claim, based on my own experience and analysis of language features, that functional programming in general, and Haskell in particular, are well suited for improving this long tail of projects. We need languages and programming techniques that allow broad codebase refactorings, significant requirements changes, improving performance in hotspots of the code, and reduced debug time. I believe Haskell checks these boxes.

  • Liked Aaron W Hsu
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    Aaron W Hsu - Does APL Need a Type System?

    45 Mins
    Talk
    Intermediate

    APL is known for its concise problem-solving expressiveness, and it is used very successfully in places where high-quality and rapid iteration are requirements, not luxuries. Static Type Systems have had tremendous success throughout the computing industry, even receiving positive HCI usability studies that demonstrate their effectiveness on a number of metrics with mainstream and functionally-oriented programming languages. This success leads many programmers to take the value of type systems as a given, especially as mission-criticality and the age of a project increase. Therefore, it comes as a surprise to many, when learning about APL, that it has spent so long as an untyped, interpreted language in domains and use cases where traditional wisdom would suggest the need for a typed, compiled language.

    But APL is not like other languages, and its unique features and historical uses warrant a careful revisiting of the question of type systems. In this talk we will explore whether or not APL needs a type system, whether it would benefit from having one, what that might look like, and how the interaction between APL and type theory might inform the design and use of type systems in general.

  • Liked Dhaval Dalal
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    Dhaval Dalal / Ravindra Jaju - Code Jugalbandi - Exploring Concurrency

    45 Mins
    Demonstration
    Beginner

    In Indian classical music, we have Jugalbandi, where two lead musicians or vocalist engage in a playful competition. There is jugalbandi between Flutist and a Percussionist (say using Tabla as the instrument). Compositions rendered by flutist will be heard by the percussionist and will replay the same notes, but now on Tabla and vice-versa is also possible.

    In a similar way, we will perform Code Jugalbandi (http://codejugalbandi.org) to see how the solution looks using different programming languages. This time the focus of Code Jugalbandi will be on exploring concurrency models in different languages. Functional Programming has made programming concurrency easier as compared to imperative programming. For deeper perspective on Code Jugalbandi, check out http://codejugalbandi.org/#essence-of-code-jugalbandi

  • Liked Anne Ogborn
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    Anne Ogborn - let over logic - What functional programming can learn from logic programming

    Anne Ogborn
    Anne Ogborn
    Partner
    The Elgin Works
    schedule 1 week ago
    Sold Out!
    45 Mins
    Talk
    Intermediate

    48 years after it's invention, logic programming remains a less frequently used paradigm.

    What can functional programming learn from logic programming?

    Unification and nondeterminism are powerful constructs not strictly relegated to logic programming. We'll look at unification, nondeterministic completion, probabilistic computation, and constraint propagation in functional contexts.

  • Liked Srihari Sriraman
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    Srihari Sriraman - Generative Testing Patterns

    Srihari Sriraman
    Srihari Sriraman
    Partner, Engineer
    nilenso
    schedule 1 week ago
    Sold Out!
    45 Mins
    Talk
    Intermediate

    Tests are good. Generative tests are better. But we don't write them often enough. Why not?

    Generative testing isn't new; John Hughes' QuickCheck is now implemented in 30 languages. Yet, it is still not an every day tool for most software teams. Why not?

    I have seen that maintaining a generative, or simulation testing suite can require the full-time attention of a few senior engineers. And over time, the tests become complex, brittle, ineffective, and hard to diagnose.

    But isn't generative testing supposed to make testing simpler, and more effective?

    I believe that it requires a rather different paradigm of thought from what we're used to with traditional testing. And recognising this paradigm shift can help us leverage it effectively.

    I'll discuss a holistic perspective of generative testing to elucidate this thought paradigm.

    Using a practical scenario, I'll discuss the patterns that emerge from this thinking, and how they address the concerns of making generative tests more effective, and maintainable.

  • Liked Anne Ogborn
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    Anne Ogborn - Introduction to Logic Programming and SWI-Prolog

    Anne Ogborn
    Anne Ogborn
    Partner
    The Elgin Works
    schedule 3 weeks ago
    Sold Out!
    480 Mins
    Workshop
    Beginner

    As machine learning matures, it is becoming obvious that we need explainable solutions. As functional programming
    matures it becomes obvious that we need inference and nondeterminism. And linked open data demands reasoning.
    This all day workshop will introduce the logic programming paradigm, in which programs are expressed as a set of
    logical rules and executed by finding proofs of queries.
    SWI-Prolog is the most highly developed and widely used language for logic programming.
    The language, which has been in continuous use in academic research settings since it's invention in 1972, provides unparalleled power. Many problems which would be difficult to express in other languages are simple in SWI-Prolog.
    SWI-Prolog is a 'batteries included' modern language, ready for real world tasks like web development and process control.
    In this dynamic hands on workshop we'll learn the basics of SWI-Prolog, and look at some of the amazing things it can do.

  • Liked Emily Pillmore
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    Emily Pillmore / Stuart Popejoy - Pact: An Open Source Language for Smart Contracts

    45 Mins
    Demonstration
    Intermediate

    In this talk we'll discuss the design and implementation of a smart contract property verification tool for Pact.

    The revolutionary idea of putting computer programs in a blockchain to create smart contracts has opened up a whole new world of possibilities. But these programs have very different characteristics from other software. This talk explores these differences, some of the challenges that have been encountered, and then discusses how Kadena is solving these problems with its smart contract language Pact. We'll discuss the design and implementation of a smart contract property verification tool for Pact. We leverage these (lack of) features to build a system capable of proving many properties of contracts via the Z3 SMT solver. We'll also give examples of real bugs caught by the system.

  • Liked Emily Pillmore
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    Emily Pillmore - A Radically New Functional Blockchain Architecture: Chainweb

    Emily Pillmore
    Emily Pillmore
    Haskell Engineer
    Kadena.io
    schedule 2 months ago
    Sold Out!
    45 Mins
    Talk
    Advanced

    Proof-of-work blockchain networks like Bitcoin, Litecoin and Ethereum are characterized by low throughput (5-15 transactions per second). Efforts to improve throughput through protocol modifications, such as block size increases, have no hope of reaching levels required to take on modern fiat-currency payment networks. However, efforts that seek to replace Proof-of-Work (Proof-of-Stake and variants) or integrate it with off-chain networks and processes (payment channels, side chains) degrade assurance, censorship resistance or trustless-ness of the original design. Recovering and elaborating on early proposals for Bitcoin scaling, we present ChainWeb, a parallel-chain architecture which can combine hundreds to thousands of Proof-of-Work blockchains pushing throughput to 10,000 transactions per second and beyond. The network transacts a single currency, using atomic and trustless SPV (Simple Payment Verification) cross-chain transfers orchestrated at the application layer with capability and coroutine support in the Pact smart contract language. Chains incorporate each other’s Merkle tree receipts to enforce a single “super branch” offering an effective hash power that is the sum of each individual chain’s hash rate. In addition to massive throughput, other benefits accrue from having a truly parallelized smart-contract blockchain system.

  • Liked Saurabh Nanda
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    Saurabh Nanda - "Refresh-driven" development with Haskell & Elm

    Saurabh Nanda
    Saurabh Nanda
    Founder
    Vacation Labs
    schedule 2 months ago
    Sold Out!
    45 Mins
    Tutorial
    Beginner

    We sorely missed the rapid "refresh-based" feedback loop available in Rails (and other dynamically typed web frameworks), while writing Haskell. Change your code, hit save, and refresh your browser!

    In this talk we will share a few tips on how we finally hit productivity nirvana with ghcid and automated code-gen.

    Best of both worlds -- rock-solid type-safety AND being able to reload code with every change.

  • Liked Nikhil Barthwal
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    Nikhil Barthwal - Implementing Event-Driven Microservices architecture in Functional language

    45 Mins
    Talk
    Advanced

    Web services are typically stateless entities, that need to operate at scale at large. Functional paradigm can be used to model these web services work and offer several benefits like scalability, productivity, and correctness.

    This talk describes how to implement Event-Driven Microservices with examples in F#. It starts with introducing Domain Driven Design to create Microservices boundaries. Using Discriminated Unions (F#'s Algebraic Data Types), the domain model can be captured as code eliminating the need for separate documentation. Moreover, using Computation expressions (F#'s Monads), one can model custom workflows easily.

    It then introduces event-driven architecture, where every external action generates an event that the system responds to. Events act as the notification messages for any significant change in state and may generate other event(s) as services invoke each other. They are immutable by nature.

    An explanation on why 2-phase commits cannot be used in Microservices having their own databases. Further the talk explains, how Event Driven Architecture solves this problem in an eventually consistent manner without sacrificing availability or partition tolerance. Distributed Sagas as a protocol for coordinating Microservices is introduced and its implementation in F# is also provided.

    Event Sourcing can be used to model the system state. Event sourcing models the state of entity as a sequence of state-changing events. Whenever the state of a business entity changes, a new event is appended. List fold operation is ideal for implementing Event sourcing where the application reconstructs an entity's current state by replaying the events. An example with F#'s List.fold is provided.

    Some aspects of evolutionary architecture are also discussed, particularly on how to evolve Microservices interface. F#'s Type providers can be used for the same though there are alternate approaches using Apache Thrift/Google Protobuf (They don't have support for F# but they do have support for C#, which F# code can leverage).

    Events and their responses can be very easily modeled with Discriminated Unions. Data immutability captures the behavior of these events, since events are immutable by nature. A service can be thought of as a function that accepts an event (input) and gives back a response (output). A service may call other services, which is equivalent to a function calling other functions or even Higher-Order functions.

    Immutability allows infinite scalability as it eliminated the need to worry about a mutex, a lock, or a race. As functional code is much more terse compares to object-oriented code, it provides productivity benefits. Its strict typing makes writing correct code easy as mismatch of types are caught at compile time.

    Most of the services are implemented as set of pure functions. These functions which have no internal state, where outputs depend only on inputs and constants and it is very easy to test such functions. The absence of internal state means that there are no state transitions to test. The only testing left is to collect a bunch of inputs that tests for all the boundary conditions, pass each through the function under test and validate the output.

    The objective of the talk is to show how to create a scalable & highly distributed web service in F#, and demonstrate how various characteristics of functional paradigm captures the behavior of such services architecture very naturally.

  • Liked Michael Snoyman
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    Michael Snoyman - Applied Haskell Workshop

    480 Mins
    Workshop
    Intermediate

    This full day workshop will focus on applying Haskell to normal, everyday programming. We'll be focusing on getting comfortable with common tasks, libraries, and paradigms, including:

    • Understanding strictness, laziness, and evaluation
    • Data structures
    • Structuring applications
    • Concurrency and mutability
    • Library recommendations

    By the end of the workshop, you should feel confident in working on production Haskell codebases. While we obviously cannot cover all topics in Haskell in one day, the goal is to empower attendees with sufficient knowledge to continue developing their Haskell skillset through writing real applications.

    Attendees will be provided with a recommended prereading list to get the most out of the workshop.

  • Liked Nikhil Barthwal
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    Nikhil Barthwal - Embracing Functional Paradigm in F# for Enhanced Productivity

    480 Mins
    Workshop
    Beginner

    F# is a relatively new primarily Functional programming language for the .NET platform. It is a statically typed managed functional language that is fully inter-operable with other .NET languages like C#, Visual Basic.NET etc. It builds on the power of Functional Paradigm and combines it with .NET Object-Oriented model enabling the developer to use the best approach for a given problem.

    This workshop introduces Functional Programming in F# from ground up. No prior experience in Functional Programming or .NET is needed, familiarity with a mainstream programming language like C++/Java/C# should be enough.

    Functional programming (FP) offers several benefits. The code tends to be terse which leads to enhanced developer productivity. FP encourages pure functions which are much easier to reason about and debug, as well as eliminates large class of bugs due to side effect free programming. Moreover, immutability leads to easy parallelization of the code. Algebraic Data Types can be used to express domain object conveniently and control state space explosion.

    F# is great practical choice for developing reliable and highly scalable real-world system that are quick and easy to develop due to the design of the language itself combined with the ability of the language to use a large no. of 3rd party libraries designed for the .NET platform.

    Unfortunately, support for multiple paradigms often leads to confusion. Newcomers tend to find the transition from object-oriented world to functional world difficult. Moreover, it often leads to abuse where developer tries to use the same old imperative style of coding in a functional language and is unable to take advantage of the features, the language has to offer.

  • Liked Ravindra Jaju
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    Ravindra Jaju / Aditya Athalye / Dhaval Dalal - The Clojuring: (hit rubber road)

    480 Mins
    Workshop
    Intermediate
    distance(clojure-code, production)→ 0

    Clojure is capable of leveraging everything your JVM provides. And you are convinced of the benefits this LISP brings to your productivity. In this workshop, we target bridging the gap between your expressive and beautiful Clojure code, and the huge, daunting world of the Enterprise. With some small, helpful steps.

    We'll specifically target

    • Going beyond the linear flows - making core.async practical
    • Confidence building measures - Clojure spec
    • Demystifying the wormhole - JVM interop
    • Practical tidbits - Introducing Clojure to your existing apps
    • Graduating - Build tooling and publishing for both library and standalone application use-cases
  • Liked Tony Morris
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    Tony Morris - Parametricity, Functional Programming, Types

    45 Mins
    Talk
    Intermediate

    In this talk, we define the principle of functional programming, then go into
    detail about what becomes possible by following this principle. In particular,
    parametricity (Wadler, 1989) and exploiting types in API design are an essential
    property of productive software teams, especially teams composed of volunteers
    as in open-source. This will be demonstrated.

    Some of our most important programming tools are neglected, often argued away
    under a false compromise. Why then, are functional programming and associated
    consequences such as parametricity so casually disregarded? Are they truly so
    unimportant? In this talk, these questions are answered thoroughly and without
    compromise.

    We will define the principle of functional programming, then go into
    detail about common problems to all of software development. We will build the
    case from ground up and finish with detailed practical demonstration of a
    solution to these problems. The audience should expect to walk away with a
    principled understanding and vocabulary of why functional programming and
    associated techniques have become necessary to software development.

  • Liked Harendra Kumar
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    Harendra Kumar - High Performance Haskell

    45 Mins
    Talk
    Intermediate

    Haskell can and does perform as well as C, sometimes even better. However,
    writing high performance software in Haskell is often challenging especially
    because performance is sensitive to strictness, inlining and specialization.
    This talk focuses on how to write high performance code using Haskell. It is
    derived from practical experience writing high performance Haskell libraries. We
    will go over some of the experiences from optimizing the "unicode-transforms"
    library whose performance rivals the best C library for unicode normalization.
    From more recent past, we will go over some learnings from optimizing and
    benchmarking "streamly", a high performance concurrent streaming library. We
    will discuss systematic approach towards performances improvement, pitfalls and
    the tools of the trade.

  • Liked Todd Sundsted
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    Todd Sundsted / Michael Ho - Making the Switch: How We Transitioned from Java to Haskell

    45 Mins
    Case Study
    Intermediate

    In this case study presentation, SumAll's CTO, Todd Sundsted, and Senior Software Engineer, Michael Ho, will discuss the move from Java to Haskell along two parallel paths. First, the business/political story — how SumAll convinced the decision makers, fought the nay-sayers, and generally managed the people impacted by the transition. Second, the technical story — how they actually replaced their Java code with Haskell code. Along the way, they will address their hopes and expectations from transitioning from Java to Haskell, and will conclude with the results they've gained and seen to date.

  • Liked Anupam Jain
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    Anupam Jain - Purely Functional User Interfaces that Scale

    Anupam Jain
    Anupam Jain
    Haskell Consultant
    S&P Global
    schedule 2 months ago
    Sold Out!
    45 Mins
    Talk
    Beginner

    A virtual cottage industry has sprung up around Purely functional UI development, with many available libraries that are essentially just variants on two distinct approaches: Functional Reactive Programming (FRP), and some form of functional views like "The Elm Architecture". After having worked extensively with each of them, I have found that none of the approaches scale with program complexity. Either they are too difficult for beginners trying to build a hello world app, or they have unpredictable complexity curves with some simple refactorings becoming unmanageably complex, or they "tackle" the scaling problem by restricting developers to a safe subset of FP which becomes painful for experienced developers who start hitting the complexity ceiling.

    In this talk I give an overview of the current Purely Functional UI Development Landscape, and then present "Concur", a rather unusual UI framework, that I built to address the shortcomings of the existing approaches. In particular, it completely separates monoidal composition in "space" (i.e. on the UI screen), from composition in "time" (i.e. state transitions), which leads to several benefits. It's also a general purpose approach, with Haskell and Purescript implementations available currently, and can be used to build user interfaces for the web or for native platforms.

    The biggest advantage of Concur that has emerged is its consistent UI development experience that scales linearly with program complexity. Simple things are easy, complex things are just as complex as the problem itself, no more. Reusing existing widgets, and refactoring existing code is easy and predictable. This means that Concur is suitable for all levels of experience.

    1. For Learners - Concur provides a consistent set of tools which can be combined in predictable ways to accomplish any level of functionality. Due to its extremely gentle learning curve, Concur is well suited for learners of functional programming (replacing console applications for learners).
    2. For experienced folks - Assuming you are already familiar with functional programming, Concur will provide a satisfying development experience. Concur does not artificially constrain you in any form. You are encouraged to use your FP bag of tricks in predictable ways, and you are never going against the grain. It's a library in spirit, rather than a framework.
  • Liked George Wilson
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    George Wilson - Laws!

    45 Mins
    Talk
    Beginner

    Laws, laws, laws. It seems as though whenever we learn about a new abstraction in functional programming, we hear about its associated laws. Laws come up when we learn about type classes like Functors, Monoids, Monads, and more! Usually laws are mentioned and swiftly brushed past as we move on to examples and applications of whatever structure we're learning about. But not today.

    In this talk, we'll learn about Functors and Monoids, paying close attention to their laws. Why should our abstractions have laws? We'll answer this question both by seeing powers we gain by having laws, and by seeing tragedies that can befall us without laws.

  • Liked Debasish Ghosh
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    Debasish Ghosh - Managing Effects in Domain Models - The Algebraic Way

    45 Mins
    Talk
    Intermediate

    When we talk about domain models, we talk about entities that interact with each other to accomplish specific domain functionalities. We can model these behaviors using pure functions. Pure functions compose to build larger behaviors out of smaller ones. But unfortunately the real world is not so pure. We need to manage exceptions that may occur as part of the interactions, we may need to write stuff to the underlying repository (that may again fail), we may need to log audit trails and there can be many other instances where the domain behavior does not guarantee any purity whatsoever. The substitution model of functional programming fails under these conditions, which we call side-effects.

    In this session we talk about how to manage such impure scenarios using the power of algebraic effects. We will see how we can achieve function composition even in the presence of effects and keep our model pure and referentially transparent. We will use Scala as the implementation language.

    In discussing effects we will look at some patterns that will ensure a clean separation between the algebra of our interface and the implementation. This has the advantage that we can compose algebras incrementally to build richer functionalities without committing to specific implementations. This is the tagless final approach that offers modularity and extensibility in designing pure and effectful domain models.

  • Liked Neeraj Sharma
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    Neeraj Sharma - BeamParticle - A Polyglot Dynamic Programming Engine

    Neeraj Sharma
    Neeraj Sharma
    Director Engineering
    redBus
    schedule 2 months ago
    Sold Out!
    45 Mins
    Talk
    Intermediate

    BeamParticle is an open source project built on top of the Erlang virtual machine (BEAM), which allows dynamic (re)programming in multiple programming languages. This project tries to take some simple decisions thereby making the life of developer easy in realizing dynamic code patching and reprogrammability. It is very easy to setup this software on any of the modern GNU/Linux distributions, although Debian packages are available for Ubuntu Xenial. The project supports six different programming languages; namely: Erlang, Elixir, Java, Python, Efene, and PHP.

    The system is deployed in a limited capacity in production within redBus to serve numerous use cases.