fuzzy search for autocomplete

[rgasper]

Describe your feature request

Adding a fuzzy-find capability to autocomplete would be awesome! It's probably my favorite feature from VSCode that I miss in Helix. In particular, the VSCode autocomplete provides the following types of suggestions that I'm missing:

• will show suggestions where the currently typed stub is in the middle
  • so if I've typed back, the autocomplete will suggest options like my_data_backup
• will show suggestions where letters in the currently typed stub show up spaced out throughout the suggestion in order
  • so if I've typed bgvn, the autocomplete will suggest options like _big_global_variable_name
• autocomplete can be configured via settings to be case-insensitive

[kirawi]

Duplicate of #1015

[archseer]

Not a duplicate.

[archseer]

However this should already work out of the box? We fuzzy filter the completion.

[sudormrfbin]

• will show suggestions where the currently typed stub is in the middle

  • so if I've typed back, the autocomplete will suggest options like my_data_backup

Suggestions in the middle don't seem to work (or they work but randomly in at least rust-analyzer).

• will show suggestions where letters in the currently typed stub show up spaced out throughout the suggestion in order

  • so if I've typed bgvn, the autocomplete will suggest options like _big_global_variable_name

This seems to work with rust-analyzer.

• autocomplete can be configured via settings to be case-insensitive

Case insensitive autocomplete doesn't work (tested with rust-analyzer and the Dart LSP).

[sudormrfbin]

So this seems to be due to filtering the completion results and removing completions that don't start with the current word:

helix/helix-term/src/commands.rs

Lines 3712 to 3722 in fb62569

	if !prefix.is_empty() {
	items = items
	.into_iter()
	.filter(|item| {
	item.filter_text
	.as_ref()
	.unwrap_or(&item.label)
	.starts_with(&prefix)
	})
	.collect();
	}

[ChrHorn]

After #3215 gets merged we could try to simply remove the prefix filtering to get full fuzzy matching. This would also fix #1807.