make "\alpha[tab]\alpha[tab]" competion possible

core/src/lib.rs

@@ -499,36 +499,34 @@ static GREEK_UPPERCASE_LETTERS: [(&str, &str); 24] = [
 
 #[must_use]
 pub fn get_completions_for_prefix(mut prefix: &str) -> (usize, Vec<Completion>) {
+	if let Some((prefix, letter)) = prefix.rsplit_once('\\') {
+		if letter.starts_with(|c: char| c.is_ascii_alphabetic()) && letter.len() <= 7 {
+			return if letter.starts_with(|c: char| c.is_ascii_uppercase()) {
+				GREEK_UPPERCASE_LETTERS
+			} else {
+				GREEK_LOWERCASE_LETTERS
+			}
+			.iter()
+			.find(|l| l.0 == letter)
+			.map_or((0, vec![]), |l| {
+				(
+					prefix.len(),
+					vec![Completion {
+						display: prefix.to_string(),
+						insert: l.1.to_string(),
+					}],
+				)
+			});
+		}
+	}
+
 	let mut prepend = "";
 	let position = prefix.len();
 	if let Some((a, b)) = prefix.rsplit_once(' ') {
 		prepend = a;
 		prefix = b;
 	}
 
-	if let Some(letter) = prefix.strip_prefix('\\') {
-		let position = prepend.len() + prepend.len().min(1);
-		if letter.starts_with(|c: char| !c.is_ascii_alphabetic()) {
-			return (0, vec![]);
-		}
-
-		return if letter.starts_with(|c: char| c.is_ascii_uppercase()) {
-			GREEK_UPPERCASE_LETTERS
-		} else {
-			GREEK_LOWERCASE_LETTERS
-		}
-		.iter()
-		.find(|l| l.0 == letter)
-		.map_or((0, vec![]), |l| {
-			(
-				position,
-				vec![Completion {
-					display: prefix.to_string(),
-					insert: l.1.to_string(),
-				}],
-			)
-		});
-	}
 	if prefix.is_empty() {
 		return (0, vec![]);
 	}