Debugging

Pragma includes a debugger that speaks the Debug Adapter Protocol. It supports JavaScript and TypeScript on Node.js, Python, and compiled Rust, C and C++ programs.

Debug adapters

Adapter	Languages	Based on	Installed with
node	JavaScript, TypeScript	vscode-js-debug	npm install -g vscode-js-debug
python	Python	debugpy	pip install debugpy
lldb	Rust, C, C++	CodeLLDB	Downloaded from the CodeLLDB releases

When you start a debug session and the adapter is missing, Pragma installs it automatically and shows the progress in a notification. CodeLLDB is stored in Pragma's local application data directory under adapters/.

Debug the current file

Open a JavaScript, TypeScript or Python file and press F5, or use Debug Current File in the Debug view of the sidebar. Pragma runs the file with node or python under the matching adapter.

Rust, C and C++ need a compiled binary, so they are debugged through a run configuration instead.

Debug a run configuration

Add a debug block to a configuration in .pragma/run.json. The configuration then gets a debug button in the Run menu.

{
  "configurations": [
    {
      "name": "dev server",
      "command": "npm run dev",
      "debug": { "adapter": "node" }
    },
    {
      "name": "django",
      "command": "python manage.py runserver",
      "debug": { "adapter": "python" }
    },
    {
      "name": "cli",
      "command": "target/debug/myapp --verbose",
      "debug": { "adapter": "lldb" }
    }
  ]
}

Field	Values	Default
adapter	node, python or lldb	Required
request	launch or attach	launch

How the command is used depends on the adapter:

Adapter	launch	attach
node	The first word is the runtime (node, npm, pnpm), the rest are its arguments	Connects to localhost:9229
python	The arguments after the interpreter are the script and its arguments; -m module is supported	Connects to localhost:5678
lldb	The first word is the binary to debug, the rest are its arguments	Not supported

The cwd and env of the configuration are passed to the program as well. For attach, start your program with the debug port open first, for example node --inspect or python -m debugpy --listen 5678.

The Debug view

The Debug view in the sidebar shows the session while it runs:

• Continue, Pause, Step Over, Step Into, Step Out and Stop.
• Call Stack with the frames of the paused thread. Select a frame to see its variables.
• Variables, expandable for objects and arrays.
• Watch expressions, added with Add watch and evaluated whenever the program pauses.
• Breakpoints across all files, each removable.

Set or remove a breakpoint by clicking the editor gutter next to a line, or with F9.

Shortcuts

Action	Default
Start / Continue Debugging	F5
Stop Debugging	Shift + F5
Step Over	F10
Step Into	F11
Step Out	Shift + F11
Toggle Breakpoint	F9

Change them in Settings > Keyboard.