Allow parsing unary -

Author: whonore

src/shunting-yard.c

@@ -53,6 +53,7 @@ static const Token NO_TOKEN = {TOKEN_NONE, NULL};
 static const Operator OPERATORS[] = {
 	{"!", 1, 1, OPERATOR_UNARY,  OPERATOR_RIGHT},
 	{"~", 1, 1, OPERATOR_UNARY,  OPERATOR_RIGHT},
+	{"-", 1, 1, OPERATOR_UNARY,  OPERATOR_RIGHT},
 	{"*", 1, 2, OPERATOR_BINARY, OPERATOR_LEFT},
 	{"/", 1, 2, OPERATOR_BINARY, OPERATOR_LEFT},
 	{"%", 1, 2, OPERATOR_BINARY, OPERATOR_LEFT},