yelm - Experimental Programming Environment for micro:bit

Yelm combines the following:

• a TypeScript library defining APIs available on the micro:bit
• an ARM Thumb machine code emitter for TypeScript
• a Blockly-based editor along with converter to TypeScript
• a webapp hosting the Blockly-based editor and ACE-based editor for TypeScript
• a command-line package manager

Yelm is an experimental platform for research on new ways of programming, especially focused on computer science education.

Name

Yelm is a city near Mt Rainier in Washington State with a name short enough for command line tool. It also stands for Your Experimental programming Language environment for Micro:bit-compatible devices.

Build

Building yelm command line tools:

tsd reinstall
npm install
jake

Building webapp:

cd webapp
tsd reinstall
npm install
jake
node server.js &
open http://localhost:3232

TODOs

package mgr + compiler

• image literals
• code in top-level scope
• only compile what's needed
• don't emit unused global vars
• testFiles: [ ... ] in yelm.json
• class methods
• class field initializers (?)
• constructors
• disallow direct references to class members (cannot copy JS semantics)
• optional arguments
• default arguments
• +=, -= etc
• proper caching for x.f++, x.f += ... etc
• lambdas returning values (maybe just works?)
• clear variables when they get out of scope to limit memory usage
• function f() {...}; control.inBackground(f) in local scope
• function f() {...}; control.inBackground(f) in global scope
• //% shim=... weight=... help=... etc insteaf of {shim:...}
• bit operators (&, |, etc)
• inline assembly
• use "(x + y) | 0" etc instead of "x + y" in simulator
• do not generate empty action bodies for shim
• check on compiler performance (1000ms on lang-test0)
• forever() seems to have issues
• skip unreferenced globals when initilized with literal
• do not DECR no-closure functions
• after uninstall pouch db throws 404 after reload

web app

• make blocks output file read only
• do not type-check while auto-completing
• scroll completion window with keyboard

converter from TD to TS (different repo)

• multi-line strings into backtick literals
• use bit operators for bits.XYZ
• fish out {shim:...} and friends
• {hints:...} -> @param x Blah, eg: 100, 200 (?)
• async is flipped
• use expr as Type not <Type> expr

Docs

We use mkdocs to generate the docs under the /docs folder. To setup mkdocs,

pip install mkdocs
mkdocs serve
open http://127.0.0.1:8000

License

MIT