[][src]Struct slog::PushFnValue

pub struct PushFnValue<F>(pub F)
    F: 'static + for<'c, 'd> Fn(&'c Record<'d>, PushFnValueSerializer<'c>) -> Result

Lazy Value that writes to Serializer

It's more ergonomic for closures used as lazy values to return type implementing Serialize, but sometimes that forces an allocation (eg. Strings)

In some cases it might make sense for another closure form to be used - one taking a serializer as an argument, which avoids lifetimes / allocation issues.

Generally this method should be used if it avoids a big allocation of Serialize-implementing type in performance-critical logging statement.

extern crate slog;
use slog::{PushFnValue, Logger, Discard};

fn main() {
    // Create a logger with a key-value printing
    // `file:line` string value for every logging statement.
    // `Discard` `Drain` used for brevity.
    let root = Logger::root(Discard, o!(
        "source_location" => PushFnValue(|record , s| {

Trait Implementations

impl<F> Value for PushFnValue<F> where
    F: 'static + for<'c, 'd> Fn(&'c Record<'d>, PushFnValueSerializer<'c>) -> Result

Auto Trait Implementations

impl<F> Unpin for PushFnValue<F> where
    F: Unpin

impl<F> Send for PushFnValue<F> where
    F: Send

impl<F> Sync for PushFnValue<F> where
    F: Sync

impl<F> RefUnwindSafe for PushFnValue<F> where
    F: RefUnwindSafe

impl<F> UnwindSafe for PushFnValue<F> where
    F: UnwindSafe

Blanket Implementations

impl<T> SendSyncUnwindSafe for T where
    T: Send + Sync + UnwindSafe + ?Sized

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> Into<U> for T where
    U: From<T>, 

impl<T> From<T> for T[src]

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<T> Borrow<T> for T where
    T: ?Sized

impl<T> BorrowMut<T> for T where
    T: ?Sized

impl<T> Any for T where
    T: 'static + ?Sized