configuration: allow tab to insert spaces at the end of a line

[jydiw]

Describe the bug

Apologies in advance if this is better highlighted as a feature request.

I would like the ability to enter tab to insert and align spaces after a line, as in the case of formatting inline comments:

def foo(bar):
    barbar = bar * 2            # doubles bar
    print(f'{bar} -> {barbar}') # print barbar
    return barbar

Environment

{
  "marimo": "0.8.15",
  "OS": "Darwin",
  "OS Version": "23.5.0",
  "Processor": "arm",
  "Python Version": "3.11.9",
  "Binaries": {
    "Browser": "128.0.6613.138",
    "Node": "--"
  },
  "Dependencies": {
    "click": "8.1.7",
    "importlib-resources": "missing",
    "jedi": "0.19.0",
    "markdown": "3.7",
    "pygments": "2.16.1",
    "pymdown-extensions": "10.9",
    "ruff": "0.6.4",
    "starlette": "0.38.4",
    "tomlkit": "0.13.2",
    "typing-extensions": "4.12.2",
    "uvicorn": "0.30.6",
    "websockets": "12.0"
  },
  "Optional Dependencies": {
    "pandas": "2.1.0"
  }
}

Code to reproduce

No response

[mscolnick]

I think this is more of a feature request - as I can see both being preferences.

Do you use a formatter? Does your formatter handle this (or undo this)?

[mscolnick]

Actually this might be a bug - seems like the tab logic is being intercepted by:

marimo/frontend/src/core/codemirror/cm.ts

Lines 97 to 109 in 33d862b

	const startCompletionAtEndOfLine = (cm: EditorView): boolean => {
	const { from, to } = cm.state.selection.main;
	if (from !== to) {
	// this is a selection
	return false;
	}
	const line = cm.state.doc.lineAt(to);
	return line.text.slice(0, to - line.from).trim() === ""
	? // in the whitespace prefix of a line
	false
	: startCompletion(cm);
	};

cc @akshayka

[akshayka]

Is a completion accidentally being triggered?

EDIT: okay I think I understand. I can take a look.

[mscolnick]

@jydiw - there was a bug in the existing code, which i have fixed here: #2394

The logic is still:

• if you are at the end of the line, it will try to open the autocomplete
• if you are in the beginning or middle, it will insert 4 spaces.

Is this ok for your use-case? If you are trying to insert the tab/spaces between you code and an inline-comment, this would work. But if you are trying to add a tab at the end of the line, this won't solve that case. Do you still hope for this to be configurable for that case?

[mscolnick]

Sorry @jydiw - scratch what I saw. I think we plan on keeping Tab as completion anywhere in the line (not just the end). So we can keep this as a FR to make it configurable.

[jydiw]

I am coming from VSCode so perhaps this request is only because of what I am used to. Its behavior is slightly different than what you describe:

• If you are at the beginning of a line, it will insert {tabwidth} spaces.
• If you are anywhere else, it will insert however many spaces needed to get to the nearest multiple of {tabwidth}.

# if i type this sentence   < tab inserts to here
# and if i type this one    < tab also inserts to here