Jove3

Aug 2007 – Feb 2008 · age 25–26

What it was

The ground-up rewrite of Jeff's web-application compiler, pulled apart into languages and layers after the first suite hit its wall. An application's reactive state became its own language: cells and database-backed sets with lifecycle hooks, compiled with a cycle check ("Cyclicness is bad") and a topological sort, plus typed input and output ports so one application could be embedded in another. Styling became a second language whose rules sliced and stretched bitmaps into button sprites, then emitted the CSS. The runtime became a JavaScript kernel with reactive cells, a batching query cache and a tiny VM through which the server told the client what to forget. The desktop editor rendered controls by screenshotting them in an embedded browser, and a layout editor running in the browser itself was begun. Two demos compiled and ran. Then it was packed up, on purpose.

Wins, for the age

At twenty-five, alone, on Visual C# Express, this primate wrote the reactive state graph as a language with typed ports, four years before the Elm architecture (2012) and Redux (2015) made that shape famous.
Server-directed cache invalidation through a client VM, four years before Meteor and Firebase live data (2012).
Asked the browser what a control looks like, arriving the same year as Dreamweaver CS4's Live View (2008), and generated sprites from stylesheets alongside Compass and SpriteMe (2009).
A file watcher that pushed a designer's saved images to the server, the same year Dropbox (2008) launched.

What it taught

The rewrite extracts the invariant. Three projects in, the dependency graph moved from inferred, to checked, to written as a language.
Separate what was tangled: the old 4,800-line compiler became ten projects, the largest new file under 900 lines.
Put the weight in the runtime so generated code stays small.
The tool must live where the output lives; the diagnosis came late, and was still right.

Genealogy

Ancestors: Career Brkz Rednova: the startup years this rewrite ran beside. HUROX: the social network whose next version it was built for. HUROX JS: the batching cache and opcode RPC, grown into a kernel. Jovian Katana V1: a designer that compiles a whole site. Jovian Suite: the cycle-checked dependency graph, now given its own language. Descendants: Adama: a declared reactive state graph, separate from any view. Kira Project: typed contracts that generate their own client stubs. Lamancha II: reactive fields and viewer formulas as a language again.

Epitaph

Here lies Jove3, which finally saw that its compiler was a reactive graph with a view attached. It was packed up on February 22, 2008, three hundred lines into the version that would have lived in the browser.