Trait frunk::hlist::HList[−][src]

pub trait HList {
    const LEN: usize;

    fn static_len() -> usize;

    fn len(&self) -> usize { ... }

    fn is_empty(&self) -> bool { ... }

    fn prepend<H>(self, h: H) -> HCons<H, Self> { ... }
}
Expand description

Typeclass for HList-y behaviour

An HList is a heterogeneous list, one that is statically typed at compile time. In simple terms, it is just an arbitrarily-nested Tuple2.

Associated Constants

Returns the length of a given HList type without making use of any references, or in fact, any values at all.

Examples

use frunk::prelude::*;

assert_eq!(<HList![i32, bool, f32]>::LEN, 3);
Run

Required methods

👎 Deprecated since 0.1.31:

Please use LEN instead

Returns the length of a given HList type without making use of any references, or in fact, any values at all.

Examples

use frunk::prelude::*;

assert_eq!(<HList![i32, bool, f32]>::static_len(), 3);
Run

Provided methods

Returns the length of a given HList

Examples

let h = hlist![1, "hi"];
assert_eq!(h.len(), 2);
Run

Returns whether a given HList is empty

Examples

let h = hlist![];
assert!(h.is_empty());
Run

Prepends an item to the current HList

Examples

let h1 = hlist![1, "hi"];
let h2 = h1.prepend(true);
let (a, (b, c)) = h2.into_tuple2();
assert_eq!(a, true);
assert_eq!(b, 1);
assert_eq!(c, "hi");
Run

Implementors