Trait OptionTraversableExt 

pub trait OptionTraversableExt<T> {
    // Required methods
    fn traverse<F, R, E>(self, f: F) -> Result<Option<R>, E>
       where F: FnOnce(T) -> Result<R, E>;
    fn traverse_opt<F, R, E>(self, f: F) -> Result<Option<R>, E>
       where F: FnOnce(T) -> Result<Option<R>, E>;
}

Extends optional values with traversal operations.

Required Methods

fn traverse<F, R, E>(self, f: F) -> Result<Option<R>, E>

where F: FnOnce(T) -> Result<R, E>,

Sequencing operation on Option type when inner type is Applicative or Monad like Result. See sequence for traverse with identity closure. Defined by Conor McBride (2005) in Haskell2010 base Data.Traversable.

Traversable structures support element-wise sequencing of Applicative effects (thus also Monad effects) to construct new structures of the same shape as the input.

class (Functor t, Foldable t) => Traversable t where
  traverse :: Applicative f => (a -> f b) -> t a -> f (t b)

From this Haskell definition t is Option and f is Result.

Examples

use alux_traversable::*;

let r: Result<_, ()> = Some(42).traverse(|x| Ok(x + 100));

assert_eq!(r, Ok(Some(142)));

fn traverse_opt<F, R, E>(self, f: F) -> Result<Option<R>, E>

where F: FnOnce(T) -> Result<Option<R>, E>,

Similar to traverse, but with inner value wrapped inside Option so it has effect of filtering None values.

Examples

use alux_traversable::*;

let r: Result<_, ()> = Some(42).traverse_opt(|x| Ok(Some(x + 100)));

assert_eq!(r, Ok(Some(142)));

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<T> OptionTraversableExt<T> for Option<T>

Extends optional values with traversal operations.

fn traverse<F, R, E>(self, f: F) -> Result<Option<R>, E>

where F: FnOnce(T) -> Result<R, E>,

Sequencing operation on Option type when inner type is Applicative or Monad like Result. See sequence for traverse with identity closure. Defined by Conor McBride (2005) in Haskell2010 base Data.Traversable.

Traversable structures support element-wise sequencing of Applicative effects (thus also Monad effects) to construct new structures of the same shape as the input.

class (Functor t, Foldable t) => Traversable t where
  traverse :: Applicative f => (a -> f b) -> t a -> f (t b)

From this Haskell definition t is Option and f is Result.

Examples

use alux_traversable::*;

let r: Result<_, ()> = Some(42).traverse(|x| Ok(x + 100));

assert_eq!(r, Ok(Some(142)));

fn traverse_opt<F, R, E>(self, f: F) -> Result<Option<R>, E>

where F: FnOnce(T) -> Result<Option<R>, E>,

Similar to traverse, but with inner value wrapped inside Option so it has effect of filtering None values.

Examples

use alux_traversable::*;

let r: Result<_, ()> = Some(42).traverse_opt(|x| Ok(Some(x + 100)));

assert_eq!(r, Ok(Some(142)));

Implementors