Krzysztof Cieślak

F# Developer, OSS contributor, Developer Experience Resercher

Łódź, Poland

Krzysztof is a photographer, globetrotter, and public speaker. He works as a Senior Research Engineer at [GitHub Next](https://next.github.com/), where he designs and builds the next generation of developer tools such as [GitHub Copilot](https://copilot.github.com/).

After the work, Krzysztof is an open-source software maintainer passionate about functional programming (especially F#), editor tooling and developer experience - he has created and maintained several OSS projects varying from [language servers](https://github.com/fsharp/FsAutoComplete) to [web frameworks](https://github.com/SaturnFramework/Saturn) to [VSCode plugins](https://github.com/ionide/ionide-vscode-fsharp).

Additionally, he is a passionate public speaker. You can meet him at many conferences around the world, where he is always trying to meet new people and learn how to make the lives of software developers better.

Area of Expertise

Information & Communications Technology

Topics

.NET
F#
Open Source Software
Web Development
Functional Programming
JavaScript
TypeScript
JavaScript Typescript
Developer Experience
Developer Tools

Reinventing MVC pattern for web programming with F#

The MVC pattern has been one of the most important architectural patterns for server-side web development - it has been implemented and popularized by frameworks like Ruby On Rail or ASP.NET MVC. However, this pattern was traditionally coupled with object-oriented programming. In the talk, I will show how to reinvent MVC pattern, and structure your web application in a functional language - F#.

The talk will cover some brief introduction to F# - modern functional programming language running on .Net platform, show how to model MVC layers using functional composition, and at the end show some examples of applying MVC pattern with Saturn - opinionated, web development framework for F# which implements the server-side, functional MVC pattern

Challenges of post-OSS world.

OSS has won. After years of convincing people to use open source software, fighting with false dichotomy between OSS and industrial, commercial software, and defending against negative biases, position of OSS is no longer disputed – it's been used by the vast majority of companies around the world, it has become default choice when choosing technologies, it powers the internet, our PCs, mobile phones and most devices we use every day, it's been accepted by huge, conservative companies that were against the whole concept a few years ago.

But were we ready for that? Have we built enough foundations for this new world, or are we just building the castle on the sand and another disaster like Heartblead is going to happen? Are assumptions on which we’ve built our mental model about OSS still correct in 2018? And what's the future of the OSS ecosystem?

LSP - magic behind your IDE

Language Server Protocol (LSP) is a project that has changed how editor tooling is built over the past two years. It is a specification of the communication between a client (editor) and a server that provides language tooling capabilities such as autocomplete, tooltips, etc. It reduces the m-times-n problem to the m-plus-n problem —similar to how Virtual Machines solve the same problem for deploying code to many platforms.

In the talk, I'll give general overview of the protocol, show some of its capabilities and explain why it is so important. I'll also dive into some sample implementations, showing you how you can leverage LSP to create rich editing experience for many different editors.

Behind F# editor tooling

F# editor tooling is in a unique position among FP languages - cross-platform, feature-rich, stable, innovative and supported and actively developed by both OSS community and commercial vendors. It's also ubiquitous - powered by the compiler which is developed with tooling in mind.

By the end of the talk, you should have an idea of how to design pieces of a compiler so that accurate tooling can be built, how constraints of a language affect tooling, and some of the challenges tooling developers face.

F# Full Stack with SAFE

F# excels at building efficient, scalable and robust web solutions. Web programming is based around receiving a single HTTP request and replying with a result, which maps very well to a stateless, functional approach. Advantages to using F# for web programming include using high level, declarative, composable code, interop with rich .Net ecosystem, and using battle-tested solutions like Kestrel and ASP.NET Core. The introduction of the [SAFE stack](https://safe-stack.github.io/) presents significant productivity gains for .NET developers to build full stack web applications in F# which run on both the server and in the user’s web browser, whilst taking advantage of F#'s functional-first feature set and capabilities, including reduce bug rates and quicker time to market.

In this talk you'll learn how to write end-to-end applications that run on the server (across Mac, Windows or Linux) and browser using F# for the entire system and effectively use the SAFE stack toolchain including .Net CLI, Fable, and Saturn tooling.

Let's code together - bringing F# to JS world.

Javascript has conquered the software development world - developers can use it in the browser, on the server, to write mobile apps, on the desktop with Electron, and even to create serverless services. Whether you like the language or not, the truth is JS developers have built an incredible ecosystem with libraries and tools to do almost anything.

During the talk, I'll show how to bring the power of F# - robust, static type system with type inference, pattern matching, and immutable design, and succinct syntax - to this vast and rich JS world using Fable - F# to JS compiler.

It will be a practical talk, showing various use cases of Fable - from building React-based web applications, through building serverless, edge web services using Cloudflare Workers, creating mobile apps, to building VSCode extensions.

Bringing the Power of AI into your Editor with GitHub Copilot

GitHub Copilot is an AI pair programmer tool that puts the collective knowledge of millions of developers right at your fingertips, directly in your IDE.

During the talk, Krzysztof, a core team member behind GitHub Copilot, will demo how Copilot works and discuss the design principles used while creating the project.

He will also dive into some of the project's technical details - how Copilot communicates with its AI, what "queries" it uses, how it processes responses, and how it integrates with various IDE to create characteristic Copilot's UX.

Workshop - SAFE Stack (focused on Fable & Elmish)

October 2019 Zürich, Switzerland

Talk for Jet.com

Challenges of post-OSS world.

April 2018 Hoboken, New Jersey, United States

The Hanselminutes podcast

F# and the functional SAFE Stack with Krzysztof Cieślak

March 2018

Workshop - Introduction to F#

January 2018 Kaunas, Lithuania

Krzysztof Cieślak

F# Developer, OSS contributor, Developer Experience Resercher

Łódź, Poland

Krzysztof Cieślak

Links

Area of Expertise

Topics

Workshop - SAFE Stack (focused on Fable & Elmish)

Talk for Jet.com

Workshop - Introduction to F#

Krzysztof Cieślak

Links