Using perfectly formatted input as list in Haskell

Question

I'm doing a program in Haskell (on the Haskell platform), and I know I'm getting perfectly formatted inputs, so the input may look like

[ ['a'], ['b'], ['c'] ]

I want Haskell to be able to take this and use it as a list of it's own. And, I'd like this list to be over multiple lines, ie, I want this to also work:

[
  ['a'],
  ['b'],
  ['c']
]

I can parse this input, but I've been told there's a way to do this easily - this is supposed to be the 'trivial' part of the assignment, but I don't understand it.

Answer 1

read "[ ['a'], ['b'], ['c'] ]" :: [[Char]]

will return [ ['a'], ['b'], ['c'] ] . If you assign the result of read to a variable that can be inferred to be of type [[Char]] , you don't need the :: [[Char]] bit.

Answer 2

Haskell列表中有一个Read类的实例，这意味着您可以使用read函数有效地解析格式化为Haskell列表的字符串，这正是您所拥有的。