pub fn command_line_arg(&mut self, n: usize) -> EvaluationResult<String> {
        match self.resolve_symbol(COMMAND_LINE_ARGS_SYMBOL, None)? {
            Value::List(args) => match args.iter().nth(n) {
                Some(value) => match value {
                    Value::String(arg) => Ok(arg.clone()),
                    _ => unreachable!(),
                },
                None => Err(EvaluationError::Interpreter(
                    InterpreterError::MissingCommandLineArg(n, args.len()),
                )),
            },
            _ => panic!("error to not intern command line args as a list"),
        }
    }
/// Read the interned command line argument at position `n` in the collection.
Read the interned command line argument at position `n` in the collection.
Read the interned command line argument at position ` n ` in the collection .
pub fn command_line_arg(&mut self, n: usize) -> EvaluationResult<String> {
        match self.resolve_symbol(COMMAND_LINE_ARGS_SYMBOL, None)? {
            Value::List(args) => match args.iter().nth(n) {
                Some(value) => match value {
                    Value::String(arg) => Ok(arg.clone()),
                    _ => unreachable!(),
                },
                None => Err(EvaluationError::Interpreter(
                    InterpreterError::MissingCommandLineArg(n, args.len()),
                )),
            },
            _ => panic!("error to not intern command line args as a list"),
        }
    }
pub fn command_line_arg ( & mut self , n : usize ) -> EvaluationResult < String > { match self . resolve_symbol ( COMMAND_LINE_ARGS_SYMBOL , None ) ? { Value :: List ( args ) => match args . iter ( ) . nth ( n ) { Some ( value ) => match value { Value :: String ( arg ) => Ok ( arg . clone ( ) ) , _ => unreachable ! ( ) , } , None => Err ( EvaluationError :: Interpreter ( InterpreterError :: MissingCommandLineArg ( n , args . len ( ) ) , ) ) , } , _ => panic ! ( " " ) , } }
Read the interned command line argument at position `n` in the collection.
Read the interned command line argument at position ` n ` in the collection .
&mut self
n
usize