Night One: March 26, 2021

19:30

Doors open

20:00—20:45

• Stephen de Gabrielle: A #lang for bibliographies?
• Mike Sperber: Teaching Language Infrastructure—Work to Do!

  The HtDP and DeinProgramm languages are wonderful tools for teaching—they support the pedagogy of systematic design, give excellent feedback, and DrRacket is an uncluttered environment appropriate for beginners.

  Yet, the user experience has fallen somewhat behind: The test-results window is clunky, Check Syntax isn’t concurrent with editing, links to documentation don’t quite work. This is all despite the fact that DrRacket in principle can do these things well.

  Remedying these problems means digging deep into historically grown code that is hard to change: I’ll talk about what the issues with the code are, what I’ve done recently both to improve the general infrastructure and to make the teaching languages use it, and what might be in store.

20:45—21:00

break

21:00—21:45

• Jens Axel Søgaard: New work with metapict
• Ryan Culpepper: The database library, the FFI, and Racket CS

  One problem the Racket database (db) library has faced is that an FFI call blocks all Racket threads from running, so a long-running query on a sqlite3 or ODBC connection can make an entire Racket application or server unresponsive. The old fix was to run queries in a separate place, but this has high overhead. Racket CS supports an alternative: running (restricted) Racket code in OS threads with shared memory. I’ve recently added support for this alternative to the db library; it requires some changes to the code, but it seems to have much lower overhead.

21:45—22:00

break

22:00—22:45

• Oliver Caldwell: Conjuring up a Racket in Neovim with a hint of Fennel

  Come with me on a journey into unfamiliar territory for Lispers, we’re going to interact with a Racket REPL from Neovim! Then we’ll take a peek behind the curtain at the other Lisp that drives the whole experience (no Vim Script here!) and the other Lisps we can talk to. I hope you enjoy this Lisp polyglot buffet!

• Daniel Brunner: title TBA

22:45—23:00

break

23:00—23:59

• Alex Harsányi: ActivityLog2: A Racket-powered fitness app
• Lîm (Danny) Tsú-thuàn: Macro as type

  We build our own environment for a type system, but reusing macro environment is possible. In this talk, I present how to convert programs to do so, and show possibilities, limitations, and future works.

Night Two: March 27, 2021

19:30

Doors open

20:00—20:45

• Tjitze Rienstra, Ranked programming with Racket
• Suzanne Soy: Why do we need macros? First-class environments as an alternative.

  Macros are used to abstract over patterns in the code, from the elimination of repetitive boilerplate to the automatic generation of complex code.

  This is exactly the job of functions: packaging a frequently-used idiom into a reusable library function. We use macros to write abstractions that cannot be written as functions:

  1. adding/reading bindings to/from the environment (let, define-struct, anaphoric, match, …)
  2. changing the order of execution (if, match, for/list, …)
  3. syntactic sugar (infix operators, anything written using syntax-parse’s ~datum or ~literal, identifier prefix/postfix annotations, …)
  4. optimisations, i.e. semantics-preserving compile-time transformations of the program
  5. tracking and propagating annotations on the code (types, source locations, tooltips, …)
  6. …

  These concepts can only be manipulated by macros because they are second-class citizens that cannot be assigned to variables, passed around by functions, and manipulated at run-time. The following features would allow these concepts to be within the reach of functions:

  1. first-class environments (an extra env parameter threaded through all functions)
  2. lazy by default, continuations, effects
  3. #%app, extensible parser, polysemic bindings (in both as a (let x = v in body) keyword and a (for x in list do body) keyword), first-class sub-expressions
  4. markers around values that should be computed at compile-time, and a perfectly hygienic rewriting metalanguage that is closer to Coq’s tactics than to macros.
  5. same: markers to track what should be done at compile-time

  This talk will give an overview of how making some concepts first-class allows most macros to be rewritten as functions.

• Jesse Alama: A macro for avoiding TODO code in production

  In the heat of development, sometimes you can’t be bothered to flesh out the definition of an annoying helper function. I’ll get to that later. So you plug in a wildly incomplete dummy value and move on to to more important things. How can you be sure that you return to that stub, and do the work that needs to be done? Mark it as a TODO item! Here’s are some simple macros that will help you to identify these items and make sure that they don’t go out into production. (Or, if they do, you’ll be notified.)

  (Not to be confused with David Thrane Christiansen’s todo-list package.)

20:45—21:00

break

21:00—21:45

• Sorawee Porncharoenwase: What’s new in Rosette 4.0

  We are working on Rosette 4.0! This version has a new technical core, which is faster and supports new features, including a more powerful synthesis library. In this talk, I will give a quick tour of the upcoming version.

• Matthijs de Jonge: Live coding with rs—MIDI sequencing in Racket

  rs is a live coding tool that lets you sequence MIDI instruments using Racket. This talk will show you can use it, how it works and what some of the benefits are of using the programming language we all know and love for making music.

21:45—22:00

break

22:00—22:45

• Joel Dueck: Beeswax: An Early-Stage Templating Language

  Many Racket templating facilities involve using read/eval on text files loaded at runtime. Beeswax is a Pollen-friendly DSL that turns document templates into normal Racket modules and functions. I’ll talk about why this might be great, how I made it, and things I still haven’t figured out.

• Eric Eide: Recent work on Xsmith

22:45—23:00

break

23:00—23:59

Round Four

Diversity Ticket

To apply for a diversity ticket, please write to the organizer (Jesse Alama) at organizers@racketfest.com.