mlsys-lab — VS Code extension

The workspace UI: a roadmap of the task bank, the statement, an editor and the grader's verdict, side by side.

Run it

npx @vscode/vsce package
code --install-extension mlsys-lab-0.1.0.vsix

Open the repository root (the folder containing src/mlsys/ and tasks/) and run mlsys-lab: Open Workspace.

Run vs Grade

Two buttons in the toolbar. Grade (⌘↵) measures the solution against the task's gates and is the only thing that marks a task solved. Run (⇧⌘↵) executes the file as a plain script and streams whatever it prints — the way to see a print, a shape, or a traceback while working.

One button, three tracks. python -m mlsys.runners.run decides how each is actually run and prints the command it used:

A .cpp that defines its own main() is compiled alone; one that does not is linked against the task's driver, so a contract implementation still runs. CUDA shows the counters the grader measures and no verdict — gates are grading.

While a process is alive the button becomes Stop, which kills the whole process group rather than orphaning the child. It is killed anyway after mlsys.runTimeoutSeconds (30 by default) or 200 KB of output, so a runaway loop cannot wedge the editor. Run needs mlsys-lab >= 0.1.2.

Typing

The editor is a textarea, so the courtesies it does not come with are written by hand. Brackets and quotes close themselves — typing the closer that is already there steps over it, backspace between a pair removes both halves, and a selection is wrapped rather than replaced. A quote following a word character is left alone, so don't and a C++ char literal type normally.

Enter keeps the indentation of the line you were on, and adds a level after a {, (, [ or, in python, a :. With the caret between a pair the closer gets its own line. Tab indents, ⇧Tab dedents, and backspace inside indentation removes a whole level.

Every edit goes through execCommand('insertText') — deprecated, and the only way to modify a textarea without clearing the native undo stack.

Projects

Part-2 projects are multi-file, so the panel does not try to be their editor: it shows the ticket, the file list and the milestones, and the code is edited in VS Code itself. Start copies the skeleton into mlsys.workDir and opens the brief; each milestone grades on its own and remembers what it cleared. Progress is stored per project and declared for Settings Sync when the first milestone is cleared — the key does not exist before that, so declaring it once at activation would have dropped it.

How grading is dispatched

The extension shells out to the engine; the language comes from the task's meta.json:

PYTHONPATH is set to the repository's src/, so a checkout works without installing the package.

Settings

• mlsys.pythonPath — interpreter used to run the grader (default python3)
• mlsys.workDir — where your solutions go, one folder per task (default ~/mlsys-lab)
• mlsys.runTimeoutSeconds — how long Run lets your code execute (default 30)