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.zip_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.zip_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([])) // []