Trait rustc_serialize::DecoderHelpers

pub trait DecoderHelpers: Decoder {
    fn read_to_vec<T, F>(&mut self, f: F) -> Result<Vec<T>, Self::Error>
    where
        F: FnMut(&mut Self) -> Result<T, Self::Error>;
}

Trait with helper functions for implementing Decodable.

This trait is implemented for everything that implements Decoder. Decodable implementations can make use of it to make their implementations easier.

Required methods

fn read_to_vec<T, F>(&mut self, f: F) -> Result<Vec<T>, Self::Error> where
    F: FnMut(&mut Self) -> Result<T, Self::Error>, 

Read a sequence into a vector.

Storing sequences as vectors is a common pattern. This method makes deserializing such sequences easier by wrapping the calls to Decoder::read_seq and Decoder::read_seq_elt.

Examples

use rustc_serialize::Decodable;
use rustc_serialize::Decoder;
use rustc_serialize::DecoderHelpers;

struct NumberSequence {
    elements: Vec<i32>,
}

impl Decodable for NumberSequence {
    fn decode<D: Decoder>(d: &mut D) -> Result<NumberSequence, D::Error> {
        d.read_struct("NumberSequence", 2, |d| {
            Ok(NumberSequence{
                elements: try!(d.read_struct_field("elements", 0, |d| {
                    d.read_to_vec(|d| { d.read_i32() })
                }))
            })
        })
    }
}

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Implementors

impl<D: Decoder> DecoderHelpers for D

fn read_to_vec<T, F>(&mut self, f: F) -> Result<Vec<T>, D::Error> where
    F: FnMut(&mut D) -> Result<T, D::Error>, 

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