Frunk Core
This library forms the core of Frunk. It should ideally be minimalistic,
containing only the fundamental building blocks of generic programming.
# Examples
```
# use frunk_core::hlist::*;
# use frunk_core::{hlist, HList};
# fn main() {
let h = hlist![1, false, 42f32];
let folded = h.foldr(hlist![|acc, i| i + acc,
|acc, _| if acc > 42f32 { 9000 } else { 0 },
|acc, f| f + acc],
1f32);
assert_eq!(folded, 9001);
// Reverse
let h1 = hlist![true, "hi"];
assert_eq!(h1.into_reverse(), hlist!["hi", true]);
// foldr (foldl also available)
let h2 = hlist![1, false, 42f32];
let folded = h2.foldr(
hlist![|acc, i| i + acc,
|acc, _| if acc > 42f32 { 9000 } else { 0 },
|acc, f| f + acc],
1f32
);
assert_eq!(folded, 9001);
// Mapping over an HList
let h3 = hlist![9000, "joe", 41f32];
let mapped = h3.to_ref().map(hlist![|&n| n + 1,
|&s| s,
|&f| f + 1f32]);
assert_eq!(mapped, hlist![9001, "joe", 42f32]);
// Plucking a value out by type
let h4 = hlist![1, "hello", true, 42f32];
let (t, remainder): (bool, _) = h4.pluck();
assert!(t);
assert_eq!(remainder, hlist![1, "hello", 42f32]);
// Resculpting an HList
let h5 = hlist![9000, "joe", 41f32, true];
let (reshaped, remainder2): (HList![f32, i32, &str], _) = h5.sculpt();
assert_eq!(reshaped, hlist![41f32, 9000, "joe"]);
assert_eq!(remainder2, hlist![true]);
# }
```
Links:
1. [Source on Github](https://github.com/lloydmeta/frunk)
2. [Crates.io page](https://crates.io/crates/frunk)