Elm is a functional programming language that compiles to performant JavaScript. At NoRedInk we have over 80,000 lines of production Elm code. It's the primary technology we use to build our Web application's user interface, which students around the world use to answer millions of questions per day. Since we began using Elm in 2015, our production Elm code has yet to cause a single runtime exception. Our error logs show plenty of crashes from our legacy JavaScript code, but none from our Elm code. We've also found our Elm-powered front-end substantially easier to scale than our previous React code base. In this talk, attendees will gain an understanding of how the Elm programming language works, what differentiates it from the other front-end technologies on the market, and practical advice for introducing it to an existing JavaScript code base. The talk will contextualize all this in an experience report of shipping production Elm code, including how it has impacted our team's velocity, technical debt, and hiring. Attendees are assumed to be comfortable with JavaScript, but no other knowledge is needed. Come see how nice your team's front-end programming experience can become!

Types, testability, tooling, paradigms, productivity, managed, native, concurrency, parallelism, performance, asynchrony, integrations, memory management, security, resilience, or, maybe, simple readability? What are the important things crossing the minds of language designers today as they build new languages or evolve the tried and trusted ones?

QCon convenes a panel of four language designers. These are people at the heart of questions like these. The computer science language panel is led by Martin Thompson and participants include:

• Brian Goetz (Java)
• Joe Duffy (Midori, C# Fork)
• Felix Klock (Rust)
• Sylvan Clebsch (Pony)

Come hear Martin ask the hard questions on choices made (past and future) and hear the discussion from the people behind some of the largest and most innovative languages in use by developers today.