My solutions to the Advent of Code 2020, for now done in Haskell (which means I skipped a bunch of days where just reading the input seemed like a huge pita).
I've written a little bit about it, particularly from a perspective of further familiarizing myself with Haskell on my blog
The Haskell solutions I've done so far will not take the raw input from AoC because, honestly, it was giving me too much of a headache trying to figure out how to read a list of numbers from the stdin. Instead the input needs to be reformatted such that it can be read in a line and parsed with read input :: [String/Int] (The type depending on the question).
To reformat using vim, as I did, you can load up the input in vim and do the following:
:%s/$/,for adding a comma after each lineVGJfor visually selecting all lines and collapsing them into a single oneA<backspace>]andI[to surround the entire thing in [] (the<backspace>is there because in step 1 we add a comma to the last line that we want to remove)
If the input is not a list of numbers but rather a list of strings, substitute step one with :%s/^\(.*\)$/"\1", for also surrounding each line in quotes.
If the puzzle has a fixed number of lines as an input (such as day 13), it can be passed raw.