static boolean isOperand ( char c ) {
  return ( c >= '0' && c <= '9' ) ;
}

static boolean isOperand ( char c ) { return ( c >= '0' && c <= '9' ) ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (return_statement (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (character_literal)) right: (binary_expression left: (identifier) right: (character_literal)))))))