119 lines
3.2 KiB
Plaintext
119 lines
3.2 KiB
Plaintext
What is Whalesong?
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Whalesong is a compiler from Racket bytecode to JavaScript.
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Why would anyone care?
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* Because it allows Racket programs to be deployed on the web.
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* Furthermore, Racket programs can access native JavaScript APIs.
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* Because my previous attempt at this produced a slower evaluator;
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this is much faster.
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What do you want to show?
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I want to show the tool in action, programs that use it
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- like World programming, FFI
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I want to show performance numbers (which means benchmarks...)
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I also want to show some of the internals, to show why the
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JavaScript context makes things more complicated.
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How do you use it?
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I have a command line tool that consumes Racket programs and
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produces standalone JavaScript applications.
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I'll be using this as the underlying evaluator for WeScheme
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Why? Performance.
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What were the technical advantages of your approach?
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Reusing the Racket compiler. Strong possibility of reusing most
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of the Racket standard library, as soon as we can bootstrap
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racket/base.
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What were some of the technical challenges?
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Supporting the features of the Racket virtual machine (tail calls,
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continuations)
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What needs to be done next?
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Adding enough primitives to run racket/base
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----------------------------------------------------------------------
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The story for the presentation:
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What's Whalesong? It's a Racket to JavaScript compiler. Whalesong
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will be used to support World programming for the web. It will be the
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evaluator for the upcoming versions of Moby Scheme, as well as
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WeScheme.
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We can support simple animations, as you'd expect:
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(Show a world program: the falling rain drops program.)
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We can do programs that have interactivity, such as:
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(Show another world program: pacman.)
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A core idea behind Whalesong is to reuse Racket's infrastructure as
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much as possible. I'm not a compiler person, so I cheat, by
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piggibacking on Matthew's work. Whalesong reuses the bytecode
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compiler, and translates the bytecode to JavaScript.
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I really am reusing the linguistic features of Racket. For example,
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let's look at the less-than-impressive program output below.
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(Show the hello world program)
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This is trivial, right? Let's look at the source code.
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(Reveal that the program was written in BF)
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Yes, this is unholy, but it works. We really are using Racket's
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underlying language features to handle reading, macro expansion, and
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optimization.
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Because we're on the web, we may even want to use functions that we've
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written in Racket as a part of regular web pages. Whalesong lets us
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do this.
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(Show the factorial example, and how it can be used by external
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JavaScript on a web page.)
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There's quite a bit that's missing: we don't yet have all of the
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primitives necessary to compile racket/base, so all Whalesong programs
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currently have to be in a language that ultimately bottoms to (planet
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dyoo/whalesong/lang/base).
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I'm going to get a release out in the following month, and the new
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versions of Moby Scheme for Smartphones, as well as the WeScheme
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environment, will be using the underlying evaluator of Whalesong.
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If you're interested, please talk to me during the break. Thanks!
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