All combinations of a list into an infinite list in haskell-CodePudding

My task is to implement a function allCombinations, in Haskell, which returns every possible combination of a given list as an infinite list.

Since i couldn't find a solution, which does not include imports, i will ask it again. I'm new to Haskell and my task is to create a function allCombinations :: [a] -> [[a]], which creates an infinite list of possible combinations. For Example: take 10 (allCombinations [True,False]), in return I should get [[],[True],[False],[True,True],[False,True],[True,False],[False,False],[True,True,True],[False,True,True],[True,False,True]]. I have found a few solutions, but all of them included imports and i need to solve this without any imports.

CodePudding user response：

You can work with recursion here. This starts with the empty list, and then you recurse where you prepend with the given list, and the items in the list, so:

allCombinations :: [a] -> [[a]]
allCombinations xs = zs
  where zs = [] : [ (y:ys) | ys <- zs, y <- xs ]