4 ms·

I’ve not used Haskell (so I have no idea of the validity) but the criticism I always hear leveled in discussions is that lazy evaluation makes runtime hard to r

I’ve not used Haskell (so I have no idea of the validity) but the criticism I always hear leveled in discussions is that lazy evaluation makes runtime hard to reason about.

smitty1e 7y ago
Haskell involves significant unlearning of imperative approaches. 99 bottles of beer with state monads gets at some of the challenge for the neophyte: http://www.99-bottles-of-beer.net/language-haskell-1360.html http://www.99-bottles-of-beer.net/language-haskell-1360.html Look at the struggle going on to deal with a "simple" piece of state.
- lgas 7y ago
  That's not a particularly great example though because 99 bottles of beer is not a particularly stateful computation. You could easily do it without state at all like this: https://gist.github.com/lgastako/2e7dfd6b1118bb408ff114a4be46eac9 https://gist.github.com/lgastako/2e7dfd6b1118bb408ff114a4be4... On the other hand this blog post http://www.haskellforall.com/2013/05/program-imperatively-using-haskell.html http://www.haskellforall.com/2013/05/program-imperatively-us... demonstrates how one of the bits of Haskell that some people find complex (lenses) can be used together with the state monad to provide an "imperative-like" experience that's even nicer than most imperative languages.
  - smitty1e 7y ago
    There were other examples, but figuring out how to deal with state is the most arcane and mystical aspect of haskell.
- labawi 7y ago
  Is it just me, or is the linked example messed up in all sorts of ways, even ignoring the use of monads and transformers? Looks like a novice trying to code in fancy ways. For instance, it defines a Beer datatype, yet stores a plain Int in the state, then casts it to Beer only to use a custom pretty printer, instead of creating a verse :: Int -> String, or verse :: Beer -> String function.
  - smitty1e 7y ago
    I'm not a Haskell expert, and the example may be dated.

I’ve not used Haskell (so I have no idea of the validity) but the criticism I always hear leveled in discussions is that lazy evaluation makes runtime hard to reason about.

smitty1e 7y ago

Haskell involves significant unlearning of imperative approaches. 99 bottles of beer with state monads gets at some of the challenge for the neophyte: http://www.99-bottles-of-beer.net/language-haskell-1360.html http://www.99-bottles-of-beer.net/language-haskell-1360.html Look at the struggle going on to deal with a "simple" piece of state.

lgas 7y ago
That's not a particularly great example though because 99 bottles of beer is not a particularly stateful computation. You could easily do it without state at all like this: https://gist.github.com/lgastako/2e7dfd6b1118bb408ff114a4be46eac9 https://gist.github.com/lgastako/2e7dfd6b1118bb408ff114a4be4... On the other hand this blog post http://www.haskellforall.com/2013/05/program-imperatively-using-haskell.html http://www.haskellforall.com/2013/05/program-imperatively-us... demonstrates how one of the bits of Haskell that some people find complex (lenses) can be used together with the state monad to provide an "imperative-like" experience that's even nicer than most imperative languages.
- smitty1e 7y ago
  There were other examples, but figuring out how to deal with state is the most arcane and mystical aspect of haskell.
labawi 7y ago
Is it just me, or is the linked example messed up in all sorts of ways, even ignoring the use of monads and transformers? Looks like a novice trying to code in fancy ways. For instance, it defines a Beer datatype, yet stores a plain Int in the state, then casts it to Beer only to use a custom pretty printer, instead of creating a verse :: Int -> String, or verse :: Beer -> String function.
- smitty1e 7y ago
  I'm not a Haskell expert, and the example may be dated.