Complete Home key toggle functionality between line start and indentation

[achaljhawar]

Complete Home key toggle functionality

Problem (#81)

Edit has a "smart home" feature that moves from text to indentation to column 0, but lacks the ability to move from column 0 back to indentation when pressing Home.

Solution

This PR completes the bidirectional toggle behavior by adding the missing functionality to move from column 0 to the first non-whitespace character, matching VSCode and Visual Studio behavior.

Implementation

• Added condition in Home key handler to check if cursor is at column 0
• Reuses existing indent_end_logical_pos() function
• Maintains Shift+Home selection support

Files Changed

• src/tui.rs: Added missing condition in Home key handler

Testing

Verified toggle works in both directions with and without selection.

[lhecker]

Now that I'm looking at this code, I notice that indent_end is only needed if logical_after.x == 0. Do you mind wrapping both if conditions into a single block like this?

if logical_after.x == 0 {
    let indent_end = tb.indent_end_logical_pos();

    if logical_before > indent_end {
        // ...
    } else if indent_end.x > 0 {
        // ...
    }
}

The reason for this is that seeking backwards in the buffer is a lot more expensive than seeking forwards. This means that indent_end_logical_pos is an "expensive" call (relatively speaking) if the current cursor is not at the line start. logical_after.x == 0 means that the cursor is at the line start and so that means the call is cheap.

[lhecker]

Wait, I just tested your changes, and they unfortunately don't work. 😅

[lhecker]

Because I was curious about it, I tried implementing it myself. The correct approach is checking for logical_before.x == 0.

I also made the optimization I described above, by moving the indent_end_logical_pos call into the let chain.