Completion

The feature you’ll meet most often is completion. In insert mode, once you’ve typed a couple of characters of a word, Helix pauses for a moment and asks the server what could come next. The answers appear in a popup at the cursor:

• Tab highlights the first entry and moves on through the list; Shift-Tab goes back (Ctrl-n and Ctrl-p do the same)
• Enter accepts the highlighted entry — with nothing highlighted it just starts a new line, so Tab first
• Escape closes the popup and keeps what you typed

Ctrl-x asks for the popup by hand when it hasn’t appeared yet. A real server proposes what makes sense at that point in the code — a method of the value you’re on, a parameter name; this one proposes every word in the file, with the functions marked as such.

Add a second call in main below: start a new line under greet("helix"), type the first three letters, and take greet from the popup — Tab, then Enter — before typing the rest of the call.