vhs

Haskell list functions implemented in v lang

VHS is an implementation of some useful functions in V that exist in the Haskell programming language Prelude

Importing the module

  v install vhs KevinDaSilvaS.vhs

In your v file import

 import kevindasilvas.vhs as vhsmod

To use a function just type:

 println(vhsmod.take(2, [1,2,3])) // [1,2]

Reverse a list

   println(vhsmod.reverse_list([1,2,3])) // [3,2,1]

   println(vhsmod.reverse_list([])) // []

Zips

For the zip function a new struct was created to store the two distinct elements:
```
pub struct Tuple<T, V> {
  pub:
    x T
    y V
}
```

Zip - zips two lists in pairs of twos

 println(vhsmod.zip([4,5,6], [false,true]))
 
 /*
 Returns
 [vhs.Tuple[int, bool]{
      x: 4
      y: false
  }, vhs.Tuple[int, bool]{
      x: 5
      y: true
  }]
 */

  println(vhsmod.zip([2, 5, 10], [1,2,3])) 
  /*
 Returns
 [vhs.Tuple[int, int]{
      x: 2
      y: 1
  }, vhs.Tuple[int, int]{
      x: 5
      y: 2
  }, vhs.Tuple[int, int]{
      x: 10
      y: 3
  }]
 */

Zip With - receives a function and two lists and apply a function on both lists return a third list

 sum_fn := fn (v1 int, v2 int) int {
    return v1+v2
 }
 println(vhsmod.with(sum_fn, [4,5,6], [1,2,3])) // [5, 7, 9]

 conc_fn := fn (v1 int, v2 int) string {
    return '$v1 <-> $v2'
 }
 println(vhsmod.with(conc_fn, [4,5,6], [1,2,3])) // ['4 <-> 1', '5 <-> 2', '6 <-> 3']

List methods

Take - takes the first n elements of a list

 println(vhsmod.take(2, [1,2,3])) // [1,2]

 println(vhsmod.take(5, [1,2,3])) // [1,2,3]

Drop - drops the first n elements of a list

 println(vhsmod.drop(2, [1,2,3])) // [3]

 println(vhsmod.drop(5, [1,2,3])) // []

Head - returns the first element of a list

 println(vhsmod.head([1,2,3])) // 1

 println(vhsmod.head([])) // panics the list should have a length of at least one element

Last - returns the last element of a list

 println(vhsmod.last([1,2,3])) // 3

 println(vhsmod.last([])) // panics the list should have a length of at least one element

Init - returns all the elements of a list except by the last one

 println(vhsmod.init([1,2,3])) // [1, 2]

 println(vhsmod.init([])) // []

Tail - returns all the elements of a list except by the first one

 println(vhsmod.tail([1,2,3])) // [2, 3]

  println(vhsmod.tail([])) // []

vhs