Auric for VS Code

Language support for Auric, the small statically-typed language for building AuroraOS apps on the Nintendo 3DS.

Coding too hard? Try Auric!

Features

Syntax coloring for .aur files: keywords, types, built-ins, the predefined colours, buttons and screens, numbers, strings, comments and operators each get their own color. Semantic coloring then picks out your functions, parameters and variables; a global that is never reassigned is colored like a constant.

Errors as you type. The extension has its own copy of the aurc front end (lexer, parser and type checker), so it flags everything aurc would reject before the C compiler runs, with aurc's own messages:

• syntax errors: a missing ; or }, an unterminated string, a stray character;
• type errors: mixing int and float, a non-bool condition, the wrong number or type of arguments, an undeclared name, a missing fn main(), a non-constant global, break outside a loop, and the rest.

Where aurc stops at its first error, the extension shows them all, and keeps going past a syntax error without piling up errors it caused. No Python or compiler is needed for this.

Hover a built-in, a constant or one of your own names to see its signature or type. Comments right above one of your functions or variables, or after it on the same line, show up as its docs.

Autocomplete for keywords, built-ins (with their parameters filled in), constants, your functions, and the variables in scope at the cursor, plus signature help while you type a call's arguments.

Snippets: main, fn, fnr, let, lett, array, if, ifelse, elseif, while, for (a counting while loop), key, gameloop, button, sound and httpget.

Build App (the ▶ button on an open .aur file, or Auric: Build App from the Command Palette) runs aurc build, and Auric: Show Generated C opens the C that aurc emit-c produces. If <name>.icon sits next to <name>.aur, the build embeds it as the app icon.

Building apps

Coloring and error checking need nothing else. To build, the extension runs the real compiler, found in this order:

1. auric.compiler.path, the standalone aurc.exe;
2. auric.compiler.auricLangPath, the auric-lang folder of an AuroraOS checkout, run as python -m compiler.aurc with Python 3.10+;
3. an auric-lang folder in or above the file's folder, or in the workspace (so files inside an AuroraOS checkout just work);
4. aurc on PATH.

Building also needs devkitARM (arm-none-eabi-gcc) on PATH. Copy the .bin it makes to SD:\Aurora\Apps\ and pick it on the AuroraOS home menu.

Settings

Path settings accept ~ and ${workspaceFolder}. In an untrusted workspace the build commands are off; coloring and checking still work.

Installing from a .vsix

code --install-extension auric-0.1.0.vsix

or Extensions view → ... → Install from VSIX....

Development

npm install
npm test               # unit tests: checker, editor services, grammar
npm run test:parity    # the checker against the real aurc (needs Python and auric-lang)
npm run test:vscode    # end to end inside VS Code ($VSCODE_PATH to use an installed one)
npm run package        # build auric-<version>.vsix

The parity and VS Code tests look for auric-lang in $AURIC_LANG, else ../aurora/auric-lang (the parity test also takes it as -- <dir>); the parity test runs $PYTHON, else python.

Press F5 in VS Code to try the extension in a development window.

The checker in src/language/ mirrors auric-lang/compiler/ (lexer.py, parser.py, typecheck.py, prelude.py). When Auric changes, update it to match and run npm run test:parity. That test mutates the example programs in test/fixtures/ thousands of ways and checks that whenever aurc accepts a program the extension reports nothing, and whenever aurc rejects one the extension reports that same error on the same line. The grammar test checks that the grammar's built-in and constant lists match prelude.ts.

License

GPL-3.0, like AuroraOS, whose compiler the checker is ported from.