Is it a reasonable practice to serialize Haskell data structures to disk just using Show/Read

Question

I've played around with the Text.Show.Pretty module, and it makes it possible to serialize out Haskell data structures like records into a nice human-readable format & still be able to deserialize them easily using read. The output format is even more readable than YAML and JSON.

Example serialized output for a Haskell record using Text.Show.Pretty:

Book
  { author = "Plato"
  , title = "Republic"
  , numbers = [ 123
              , 1234
              ]
  }

Coming from the Ruby world, I know that YAML and JSON are most Rubyists' preferred format for serializing data structures. Are Haskell Show and Read instances used often to achieve the same end in Haskell?

Answer 1

For big structures, I wouldn't recommend it. read is slower than molasses. Anecdote time: I have a program named yeganesh. Conceptually, it's pretty simple: read in a [(String,Double)] with about 2000 elements and dump out the keys sorted by their elements. I used to store this using Show/Read, but found that switching to a custom printer and parser sped up the program by a factor of 8. (Note: it's not that the parsing sped up by a factor of eight. The whole program sped up by a factor of eight. That means the parsing sped up by a bigger factor than that.) That made the difference between uncomfortably long pauses and instant gratification.