Functional Programming for the Long Haul

schedule Dec 14th 09:30 AM - 10:15 AM place Crystal 1 people 41 Interested

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.

 
10 favorite thumb_down thumb_up 0 comments visibility_off  Remove from Watchlist visibility  Add to Watchlist
 

Outline/structure of the Session

  • The common language and tooling assessment process
  • How does FP measure up in such an analysis?
  • The blindspots such an analysis leads to
  • Examples of real world success with software maintenance
  • How we can bring this back to industry

Learning Outcome

Attendees will come away with a deeper understanding of why functional programming is a valuable tool for making better software. Furthermore, they will be empowered to go back to work and promote usage of functional programming from a business standpoint.

Target Audience

Those interested in understanding the practical benefits functional programming and Haskell can bring to software engineering in industry.

Prerequisite

No prerequisites, though familiarity with the common problems with maintaining large, production codebases will certainly help.

schedule Submitted 6 months ago

Comments Subscribe to Comments

comment Comment on this Submission

  • Liked Saurabh Nanda
    keyboard_arrow_down

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

    Saurabh Nanda
    Saurabh Nanda
    Founder
    Vacation Labs
    schedule 5 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 Raghu Ugare
    keyboard_arrow_down

    Raghu Ugare / Vijay Anant - (Why) Should You know Category Theory ?

    45 Mins
    Talk
    Intermediate

    Category Theory has been found to have a vast field of applications not limited to programming alone.

    In this fun-filled talk (Yes! We promise!) , we want to make the audience fall in love with Math & Category Theory in general, and Haskell in particular.

    We will address questions such as below:

    • What is the mysterious link between the abstract mathematical field of Category Theory and the concrete world of real-world Programming ? And why is it relevant especially in Functional Programming?
    • Most of all, how can You benefit knowing Category Theory ? (Examples in Haskell)

  • Liked Harendra Kumar
    keyboard_arrow_down

    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 Tony Morris
    keyboard_arrow_down

    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 Michael Ho
    keyboard_arrow_down

    Michael Ho - Making the Switch: How We Transitioned from Java to Haskell

    Michael Ho
    Michael Ho
    Sr. Software Engineer
    SumAll
    schedule 5 months ago
    Sold Out!
    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
    keyboard_arrow_down

    Anupam Jain - Purely Functional User Interfaces that Scale

    Anupam Jain
    Anupam Jain
    Haskell Consultant
    S&P Global
    schedule 5 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 Debasish Ghosh
    keyboard_arrow_down

    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 George Wilson
    keyboard_arrow_down

    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 Michael Snoyman
    keyboard_arrow_down

    Michael Snoyman - Applied Haskell Workshop

    Michael Snoyman
    Michael Snoyman
    Vice President of Engineering
    FP Complete
    schedule 6 months ago
    Sold Out!
    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.

  • Liked Jayaram Sankaranarayanan
    keyboard_arrow_down

    Jayaram Sankaranarayanan - YAAeM : Yet Another Attempt To Explain M

    45 Mins
    Talk
    Beginner

    It's another attempt to explain Monads to all those who are curious of this M-word.

    The famous Mars Rover problem is used to demonstrate a solution for it using basic Haskell tools and then introduces Monads and demonstrates a solution using the State Monad.

  • Liked Brian McKenna
    keyboard_arrow_down

    Brian McKenna - Starting Data61 Functional Programming Course

    Brian McKenna
    Brian McKenna
    Functional Programmer
    Atlassian
    schedule 5 months ago
    Sold Out!
    90 Mins
    Workshop
    Beginner

    Following Tony and Alois' Introduction to Haskell syntax and tools, we will work through the first few modules of Data61's Functional Programming Course. These modules cover writing functions for the optional and list data types.

    We will complete enough exercises to cover basic data types, functions and polymorphism. We'll practice the techniques of equational reasoning, parametricity and type/hole driven development. After completing these modules, you should be able to use the techniques to attempt most other exercises in the repository.

    This workshop has the same requirements as Tony's introduction, along with a download of a recent version of the fp-course repository (https://github.com/data61/fp-course).

  • Liked Luka Jacobowitz
    keyboard_arrow_down

    Luka Jacobowitz - Testing in the world of Functional Programming

    Luka Jacobowitz
    Luka Jacobowitz
    Software Engineer
    codecentric AG
    schedule 6 months ago
    Sold Out!
    45 Mins
    Demonstration
    Intermediate

    Testing is one of the most fundamental aspects of being a software developer. There are several movements and communities based on different methodologies with regards to testing such as TDD, BDD or design by contract. However, in the FP community testing is often not a large topic and is often glossed over. While it’s true that testing in functional programming tends to be less important, there should still be more resources on how to create tests that add actual value.

    This talks aims to provide exactly that, with good examples on how to leverage property based testing, refinement types and the most difficult part: figuring out how to test code that interacts with the outside world.

  • Liked Mark Hibberd
    keyboard_arrow_down

    Mark Hibberd - Property Based Testing

    Mark Hibberd
    Mark Hibberd
    Head of Technology
    Kinesis
    schedule 5 months ago
    Sold Out!
    90 Mins
    Workshop
    Beginner

    Building on the earlier two introductions to functional programming with types, property based testing is the extra verification technique you need to ensure working software. We will work through the patterns of property based testing, starting with simple functions, working up to verification of a larger program.

    By the end of this workshop participants will have a better understanding of the advantages of property based tests over example based tests, as well as acquiring the skills and confidence to start applying property based testing techniques to their current work.

    This workshop has the same requirements as Tony's introduction, and will require a recent clone of the workshop repository available at https://github.com/markhibberd/property-based-testing-workshop.

  • Liked Tony Morris
    keyboard_arrow_down

    Tony Morris - Let's Lens

    Tony Morris
    Tony Morris
    Sr. Software Engineer
    Queensland FP Lab, Data61
    schedule 4 months ago
    Sold Out!
    480 Mins
    Workshop
    Intermediate

    Let's Lens presents a series of exercises, in a similar format to the Data61 functional programming course material. The subject of the exercises is around the concept of lenses, initially proposed by Foster et al., to solve the view-update problem of relational databases.

    The theories around lenses have been advanced significantly in recent years, resulting in a library, implemented in Haskell, called lens.

    This workshop will take you through the basic definition of the lens data structure and its related structures such as traversals and prisms. Following this we implement some of the low-level lens library, then go on to discuss and solve a practical problem that uses all of these structures.

  • Liked Aaron W Hsu
    keyboard_arrow_down

    Aaron W Hsu / Dhaval Dalal / Morten Kromberg - Array-oriented Functional Programming

    90 Mins
    Workshop
    Beginner

    APL is the original functional programming language, the grand-daddy, the Godfather, and the old workhorse. But don't let Grandpa's age fool you. APL programmers have been leveraging the use of functional programming with arrays long before it was cool to be chasing pointers in an ADT using statically typed pattern matching, and they've refined their own style and approach to getting the most from a "functional paradigm."

    In this workshop, you will have the chance to spend some time thinking like a functional array programmer. What makes it different? How does the code look at the end? What thought process do you go through to get there? Get a chance to play around with some classic problems and try solving them "the APL way."

    Taijiquan Classics say, "Four ounces deflects a thousand pounds."

    APLers might say instead, "Fifty characters solve a thousand problems."

  • Liked Jayaram Sankaranarayanan
    keyboard_arrow_down

    Jayaram Sankaranarayanan - Ring Of Effects Architecture Driven by FP!

    20 Mins
    Experience Report
    Beginner

    This talk shares case study on how an application's design and architecture evolved when functional principles were applied and application was refactored.

    The transformation of the architecture and how developers understood the structure of the application is also discussed.

    It starts with outlining the basic use case, initial implementation tech stack and high level design and how iteratively the design was changed by applying the following FP principles.

    1. No mutable global state

    2. Use pure functions

    3. Effects as Data and Restrict effects to outer ring of the application

  • Liked Mark Hibberd
    keyboard_arrow_down

    Mark Hibberd - Hanging on in Quiet Desperation: Time & Programming

    Mark Hibberd
    Mark Hibberd
    Head of Technology
    Kinesis
    schedule 3 months ago
    Sold Out!
    45 Mins
    Talk
    Intermediate

    Time has a profound impact on the complexity of the systems we build.

    A significant amount of this software complexity comes from either an inability to recall previous states or the inability to understand how a state was arrived at.

    From the foundations of AI, LISP and functional programming [1], to causality in distributed systems [2], to the more grungy practices of immutable infrastructure, or the unreasonable effectiveness of fact-based approaches to large scale data systems; the ability to adequately cope with time, and the change and conflict it inevitably creates, is a common thread to being able to build and reason about these systems.

    This talk looks at the impact of time on system design. We will walk through examples of large-scale systems and their battles with complexity. At the end of the talk, the audience should start to see the common spectre of time and have an appreciation of how understanding time is fundamental to maintaining clarity, correctness and reliability in systems.

    [1] Situations, Actions, and Causal Laws
    John McCarthy
    http://www.dtic.mil/dtic/tr/fulltext/u2/785031.pdf

    [2] Times, Clocks and the Ordering of Events in a Distributed System
    Leslie Lamport
    https://amturing.acm.org/p558-lamport.pdf

  • Liked Tanmai Gopal
    keyboard_arrow_down

    Tanmai Gopal - Using Haskell to build a performant GraphQL to SQL compiler

    Tanmai Gopal
    Tanmai Gopal
    Founder
    Hasura
    schedule 4 months ago
    Sold Out!
    45 Mins
    Case Study
    Intermediate
    1. Motivation/Problem statement: Lifecycle of a GraphQL query
    2. Design Goals
    3. Why Haskell
    4. Compiler implementation details:
      1. Fast GraphQL parsing with parser combinators
      2. Modelling and manipulating the GraphQL AST with algebraic data types
      3. Software Transactional Memory: Concurrency constructs for scaling GraphQL subscriptions
    5. Summary with performance benchmarks
  • Liked Zubin Duggal
    keyboard_arrow_down

    Zubin Duggal - The Future of Haskell Tooling

    20 Mins
    Talk
    Intermediate

    Haskell tooling, particularly editor and IDE integration has been sorely lacking for years. This talk will be a broad overview of the state of Haskell tooling, and the challenges faced by it. It will be derived from the experience of working on two summer of code projects trying to improve Haskell tooling.

    For tooling users, we will discuss different Haskell tools available today(intero, haskell-ide-engine, ghcid etc.), their differences and trade-offs with respect to build tool support(stack, cabal, new-build, nix, make etc.), editor integration, features, limitations and speed.

    We will go over the approach taken by haskell-ide-engine and the Language Server Protocol in order to solve these problems. Then we will discuss the new .hie file format designed to make information about Haskell source collected by GHC more accessible to tooling and users.

    Finally, for budding tooling writers, we will discuss the various approaches to writing programs that extract information from and manipulate Haskell source, and their pros and cons:

    • The GHC API
      • Via ghc-mod and haskell-ide-engine
    • ghc-exactprint
    • haskell-src-extras
    • GHC source plugins
    • .hie files
  • Liked Ravi Mohan
    keyboard_arrow_down

    Ravi Mohan - Experience Report: Building Shin - A Typed Functional Compiler For Computational Linear Algebra Problems.

    Ravi Mohan
    Ravi Mohan
    CEO
    AxiomChoice
    schedule 6 months ago
    Sold Out!
    45 Mins
    Talk
    Intermediate

    Abstract: I wrote a distributed (mostly) Functional Compiler in Scheme, OCaml and Elixir that incorporates knowledge of Computational Linear Algebra and domain specific knowledge to generate highly optimized linear algebra code from specification of problems. This talk is about lessons learned in the process.

    The problem:
    In every domain that uses computational linear algebra (which is all of engineering and science), we encounter the 'how to optimize a linear algebra expression into an optimized sequence of BLAS (or LAPACK or $linear_algera library) kernel calls' problem.

    Example: (if the math equations make you want to tear your hair out and go jump off a cliff, don't worry, it is just an example, you don't have to grok it. Just skim the equations The basic problem being addressed here is that solving such equations with code takes up a lot of effort and time from experts in computational linear algebra)


    Here is a linear algebra expression from a genetics problem , specifically GWAS -Genome Wide Association Studies, looking for significant associations for millions of genetic markers- where the essence of the problem [1] comes down to generating the most efficient algorithm possible that solves these equations

    This in turn involves solving a 2 dimensional sequence of Generalized Least Squared Problems of the form

    The algorithms to solve these can be directly coded up in Matlab or Julia. But there are problems with this approach, with this specific problem.


    1. For different input sizes, different algorithms give the most optimal performance. Which algorithm do you code up?


    2. Even for a given input size, there are multiple algorithms that compute the same result, but have differing computational characteristics depending on the hardware etc. How do you generate the optimal algorithm for your hardware ?


    3. Most importantly the structure of *this* specific problem allows optimizations that are specific to the problem which are not built into generic linear algebra routines. (Obviously, one can't expect MATLAB to incorporate problem specific information for every scientific/engineering problem ever). The GLS problems are connected to others, thus saving intermediate results can save hours of computation vs calculating every GLS problem from scratch

    In practice, one needs to be an expert in Computational Linear Algebra to come up with the optimized algorithm for a domain specific problem, and then write (say Fortran) code to use BLAS, LAPACK etc optimally to actualize this algorithm, often with much iteration, often consuming 100s of hours.

    The Solution:


    Incorporating this 'expert knowledge' into a compiler speeds up the time taken to arrive at the best solution (often by a factor of 100 or 1000), and allows Computational Linear Algebra experts to do more interesting things, like focus on their research.

    For this particular problem, the above equations, and additional knowledge of the problem domain are the input into an expression compiler. The output is highly efficient and 'proved correct' code

    In compiler terms, incorporating domain knowldege into the compilation process results in being able to apply optimizations to the generated Syntax Trees/Graphs, resulting in optimal algorithms. (note: the output of the compiler is a program in another language- say Matlab).

    In essence, "Domain Specific Compilers" consume knowledge about the structure of a problem and generate optimized code that solves that problem.

    Shin is one such compiler. It consumes a problem description and outputs highly efficient Julia code that solves the problem.

    This talk focuses on the engineering challenges I faced in building this compiler, with a special focus on the approaches that failed [5]

    Trivia:

    "Shin" is the Hebrew letter, not the English word meaning 'front of the leg between knee and ankle' ;-).

    Every company uses names from a common theme to name their servers and components - Athena, Zeus, Hercules , or Thor, Loki, Odin, or Jedi, Sith, Skywalker etc. We use Hebrew words, so we have Ruach, Melekh, Malkuth etc..