Trait rustc_serialize::EncoderHelpers [−] [src]

pub trait EncoderHelpers: Encoder {
    fn emit_from_vec<T, F>(&mut self, v: &[T], f: F) -> Result<(), Self::Error> where F: FnMut(&mut Self, &T) -> Result<(), Self::Error>;
}
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Trait with helper functions for implementing Encodable.

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

Required Methods

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Emit a vector as a sequence.

Storing sequences as vectors is a common pattern. This method makes encoding such sequences easier by wrapping the calls to Encoder::emit_seq and Encoder::emit_seq_elt.

Examples

use rustc_serialize::Encodable;
use rustc_serialize::Encoder;
use rustc_serialize::EncoderHelpers;

struct NumberSequence {
    elements: Vec<i32>,
}

impl Encodable for NumberSequence {
    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_struct("NumberSequence", 1, |s| {
            s.emit_struct_field("elements", 0, |s| {
                s.emit_from_vec(&self.elements, |s,e| {
                    s.emit_i32(*e)
                })
            })
        })
    }
}

Implementors