Fixed unary minus

src/lex/symbol.rs

@@ -6,6 +6,8 @@ pub enum Symbol {
 	Semicolon,
 	OpenBrace,
 	CloseBrace,
+	OpenParen,
+	CloseParen,
 }
 
 pub fn parse_symbol(input: &str) -> Option<(Token, &str)> {
@@ -16,6 +18,8 @@ pub fn parse_symbol(input: &str) -> Option<(Token, &str)> {
 		';' => Some((Token::Sym(Symbol::Semicolon), input)),
 		'{' => Some((Token::Sym(Symbol::OpenBrace), input)),
 		'}' => Some((Token::Sym(Symbol::CloseBrace), input)),
+		'(' => Some((Token::Sym(Symbol::OpenParen), input)),
+		')' => Some((Token::Sym(Symbol::CloseParen), input)),
 		_ => None
 	}
 }