Modelita

A little language for shapes.

Try it: modelita.vercel.app: a tour, a cheatsheet and a playground, all running the C implementation as WebAssembly.

k[top](0.8) storey(1.2)^3 x[+z]{tower} C

Read right to left: a cube (C), its top extruded (x[+z]) and labelled tower, a storey added three times, and a tent on the top. Each operator acts only on the faces its [selector] picks. Conway's polyhedron operators (d a t k g …) are part of the language too, so t I is still a football.

A word is plain text. Any implementation that follows the spec builds exactly the same shape from it, so a word can be stored, sent and rebuilt anywhere.

What's here

Path	What
SPEC.md	the language, precisely enough to implement from
tests/	the conformance suite: programs and the dumps they must produce, plus a runner that works with any implementation
racket/	the reference implementation
c/	the whole language in one C99 header, modelita.h, plus a command-line tool
web/	the site: a tour, a cheatsheet, and a playground with an editor and 3D view, all running the C header as WebAssembly

Try it

make -C c                                        # build the C version
c/modelita -e "k[top](0.9) x[+z](0.6) C"         # the dump of one word
c/modelita examples/demo.mdl                     # a program; export lines write .obj files
python3 tests/run.py -- c/modelita               # the conformance suite
python3 tests/run.py -- racket racket/cli.rkt    # ... against the Racket reference
make -C web serve                                # the site, at http://localhost:8642
make check                                       # every implementation against the suite

Writing an implementation

1. Read SPEC.md.
2. Make a command that runs a program file and prints the dump described in tests/README.md.
3. Run python3 tests/run.py -- <your command> until every case passes.

Status

Draft 1 of the spec, extended since with mirror (§5.4), the transforms move, turn and stretch (§5.5), several bodies: +, array and spin (§3, §5.6), and selector parameters (§6). Two implementations, Racket and C, pass the same suite, and the C one also passes it compiled to WebAssembly. They also agree on thousands of randomly generated words.

Planned next:

• bindings for other languages, starting with Python.

The DrRacket #lang and the studio from local-ops will be moved over on top of racket/.

License

MIT. See LICENSE.