Question

我使用nom解析器返回Vec<PdlItem>。我不明白为什么parsable_buffer需要超越最后一行;或如何解决错误。 res拥有Vec<PdlItem>，所以我的期望是它会被移入结果中。

我对parsable_buffer毫无用处，我错过了什么？

pub enum PdlError {
    ParseError,
}

#[derive(Debug, PartialEq, Clone)]
pub enum PdlItem<'a> {
    FOO,
    STR(&'a str, Option<&'a str>, &'a str),
    NUM(&'a str, Option<&'a str>, f32),
    VNUM(&'a str, Option<&'a str>, Vec<f32>),
    VSTR(&'a str, Option<&'a str>, Vec<&'a str>),
}

pub fn pdl_to_tokens(buffer: &[u8]) -> Result<Vec<PdlItem>, PdlError> {
    // Remove comments
    let parsable_buffer: Vec<u8> = remove_comments(buffer);
    let res: IResult<&[u8], Vec<PdlItem>> = parse_pdl(&parsable_buffer);
    match res {
        IResult::Done(_, o) => {
            println!("Parsed ok {}", o.len());
            Ok(o.to_owned())
        } // Also tried .clone()
        IResult::Incomplete(i) => {
            println!("{:?}", i);
            Err(PdlError::ParseError)
        }
        IResult::Error(e) => {
            println!("Error {}", e);
            Err(PdlError::ParseError)
        }
    }
}

错误是

error[E0597]: `parsable_buffer` does not live long enough
  --> src\pdl_serialiser.rs:24:26
   |
24 |     let res = parse_pdl(&parsable_buffer);
   |                          ^^^^^^^^^^^^^^^ does not live long enough
...
31 | }
   | - borrowed value only lives until here
   |
note: borrowed value must be valid for the anonymous lifetime #1 defined on the function body at 21:1...
  --> src\pdl_serialiser.rs:21:1
   |
21 | / pub fn pdl_to_tokens(buffer : &[u8]) -> Result<Vec<PdlItem>,PdlError> {
22 | |     // Remove comments
23 | |     let parsable_buffer = remove_comments(buffer);
24 | |     let res = parse_pdl(&parsable_buffer);
...  |
30 | |     }
31 | | }
   | |_^

为什么丢弃的局部变量需要更长的寿命？

0 个答案: