diff --git a/src/FileType.php b/src/FileType.php
index fa442e6..c800c9b 100644
--- a/src/FileType.php
+++ b/src/FileType.php
@@ -23,6 +23,7 @@ class FileType {
 					'select', 'then', 'time', 'until', 'while', 'declare',
 				],
 				['set'],
+				operators: ['[[', ']]'],
 				slcs: '#',
 				mcs: '',
 				mce: '',
@@ -103,6 +104,12 @@ class FileType {
 					'usize', '&str', 'Copy', 'Drop', 'From', 'Into', 'None', 'Self', 'Send', 'Some',
 					'Sync', 'bool', 'char', 'i128', 'u128', 'Box', 'Err', 'Ord', 'Vec', 'dyn', 'f32',
 					'f64', 'i16', 'i32', 'i64', 'str', 'u16', 'u32', 'u64', 'Eq', 'Fn', 'Ok', 'i8', 'u8',
+					'&mut self', '&mut', '&self', 'self',
+				],
+				[
+					'...', '=>', '..', '>>=', '<<=', '--', '%=', '>>', ':=', '++', '/=', '<<', '>=',
+					'<-', '^=', '*=', '<=', '||', '|=', '-=', '!=', '==', '&&', '&=', '+=', '..=',
+					'.',
 				],
 				hasCharType: true,
 				highlightCharacters: true,
diff --git a/src/Row.php b/src/Row.php
index 8015c86..9d7dab9 100644
--- a/src/Row.php
+++ b/src/Row.php
@@ -170,6 +170,11 @@ class Row {
 		$this->update();
 	}
 
+	/**
+	 * Set the contents of the Row
+	 *
+	 * @param string $chars
+	 */
 	public function setChars(string $chars): void
 	{
 		$this->chars = $chars;
@@ -274,10 +279,17 @@ class Row {
 		}
 	}
 
+	/**
+	 * Highlight number literals
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightNumber(int &$i, Syntax $opts): bool
 	{
 		$char = $this->render[$i];
-		if ($opts->numbers() && is_digit($char))
+		if ($opts->numbers() && is_digit($char) && $this->hl[$i] === Highlight::NORMAL)
 		{
 			if ($i > 0)
 			{
@@ -311,9 +323,18 @@ class Row {
 		return false;
 	}
 
-	protected function highlightWord(int &$i, array $keywords, int $syntaxType): bool
+	/**
+	 * Highlight keywords and/or operators
+	 *
+	 * @param int $i
+	 * @param array $keywords
+	 * @param int $syntaxType
+	 * @param bool $requireSeparator
+	 * @return bool
+	 */
+	protected function highlightWord(int &$i, array $keywords, int $syntaxType, bool $requireSeparator = true): bool
 	{
-		if ($i > 0)
+		if ($i > 0 && $requireSeparator)
 		{
 			$prevChar = $this->render[$i - 1];
 			if ( ! is_separator($prevChar))
@@ -341,6 +362,14 @@ class Row {
 		return false;
 	}
 
+	/**
+	 * Highlight a single-char character from a list of provided keywords
+	 *
+	 * @param int $i
+	 * @param array $chars
+	 * @param int $syntaxType
+	 * @return bool
+	 */
 	protected function highlightChar(int &$i, array $chars, int $syntaxType): bool
 	{
 		if ($this->hl[$i] !== Highlight::NORMAL)
@@ -361,21 +390,49 @@ class Row {
 		return false;
 	}
 
+	/**
+	 * Highlight primary keywords
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightPrimaryKeywords(int &$i, Syntax $opts): bool
 	{
 		return $this->highlightWord($i, $opts->keywords1, Highlight::KEYWORD1);
 	}
 
+	/**
+	 * Highlight secondary keywords
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightSecondaryKeywords(int &$i, Syntax $opts): bool
 	{
 		return $this->highlightWord($i, $opts->keywords2, Highlight::KEYWORD2);
 	}
 
+	/**
+	 * Highlight language-specific operators
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightOperators(int &$i, Syntax $opts): bool
 	{
-		return $this->highlightWord($i, $opts->operators, Highlight::OPERATOR);
+		return $this->highlightWord($i, $opts->operators, Highlight::OPERATOR, false);
 	}
 
+	/**
+	 * Highlight common single-character operators
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightCommonOperators(int &$i, Syntax $opts): bool
 	{
 		if ( ! $opts->commonOperators())
@@ -390,6 +447,12 @@ class Row {
 		);
 	}
 
+	/**
+	 * Highlight brackets and braces
+	 *
+	 * @param int $i
+	 * @return bool
+	 */
 	protected function highlightCommonDelimeters(int &$i): bool
 	{
 		return $this->highlightChar(
@@ -399,6 +462,13 @@ class Row {
 		);
 	}
 
+	/**
+	 * Highlight character literals
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightCharacter(int &$i, Syntax $opts): bool
 	{
 		if (($i + 1) >= $this->rsize)
@@ -431,6 +501,13 @@ class Row {
 		return false;
 	}
 
+	/**
+	 * Highlight single-line comments
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightComment(int &$i, Syntax $opts): bool
 	{
 		if ( ! $opts->comments())
@@ -452,6 +529,13 @@ class Row {
 		return false;
 	}
 
+	/**
+	 * Highlight quote-delimited string literals
+	 *
+	 * @param int $i
+	 * @param Syntax $opts
+	 * @return bool
+	 */
 	protected function highlightString(int &$i, Syntax $opts): bool
 	{
 		$char = $this->render[$i];
@@ -495,6 +579,9 @@ class Row {
 		return false;
 	}
 
+	/**
+	 * Highlight PHP code based on pre-parsed tokens
+	 */
 	protected function highlightPHP(): void
 	{
 		$rowNum = $this->idx + 1;