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As someone who has been curious about Haskell, I'm happy to hear someone else say this. The way this article was written feels exactly like the "ruby fever" of

by iamdev 13y ago

As someone who has been curious about Haskell, I'm happy to hear someone else say this. The way this article was written feels exactly like the "ruby fever" of 5 years ago.

zwieback 13y ago
Or all the other fevers we've suffered through. Haskell seems like an attractive language but I wish boosters wouldn't advocate their languages as the fix to the problems of large-scale software engineering issues when there's little or no evidence for their claims.
- chongli 13y ago
  Well, the problem with this is that the evidence is locked up in company trade secrets. A lot of the big commercial users of Haskell are in finance and all their code is under lock and key.
- cschneid 13y ago
  There was a cool talk on "The Haskell Chat" episode two [1] that goes over how haskell is used in a large team, some members with expert haskell knowledge, some as just technical end-users of the libraries. I found it really interesting to see how a large team can deal with a real haskell project. [1]: http://www.haskellcast.com/episode/002-don-stewart-on-real-world-haskell/ http://www.haskellcast.com/episode/002-don-stewart-on-real-w...
chongli 13y ago
"ruby fever" of 5 years ago The difference is that Haskell is a very principled language. All of the claims and excitement are actually backed up by mathematical proofs. Pure functions really do make your code easier to maintain. And no, it's not the case that Haskell is the only language which allows you to write pure functions. People who try to claim that are being silly and dishonest. Haskell's advantage is that its type system allows you to know at a glance whether or not a function is pure.
- tmhedberg 13y ago
  While I fully agree that pure code is far easier to maintain than impure code, and the advantages of Haskell are numerous, I think it is a bit strong to state that such claims are backed up by mathematical proofs. Ease of maintenance is a fundamentally subjective claim that cannot be proven, but must be borne out by individual experience (as it has been for you, me, and many others).
  - chongli 13y ago
    Ease of maintenance is a fundamentally subjective claim that cannot be proven, but must be borne out by individual experience (as it has been for you, me, and many others). I disagree. You can make objective measurements of maintainability. You can look at cyclomatic complexity and reusability (both wins for pure functions). You can test how often changes lead to bugs and how often the errors are caught. There are many instances of Haskell code where there is only one sensible implementation of a function, given its type. Hell, some Haskell libraries have even been formally verified though admittedly that is done with external packages. I will agree on one thing, though: you do run into trouble when you throw around the word all (or indeed any absolute) without actually meaning it.
    - bunderbunder 13y ago
      > You can look at cyclomatic complexity and reusability (both wins for pure functions). Yes, those are both wins for pure functions. But even there you need an asterisk, because side effects do have their place - the fact of the matter is, the primary task of most real-world software can be summed up as "manipulating mutable state". In light of that I don't think you can necessarily jump from the observation that there are many situations where pure functions are easier to work with than impure ones to the conclusion that pure functions are inherently more maintainable. But even if that were granted for the sake of argument, it's not much of a win for Haskell. The ability to create pure functions is a feature of every language that has been invented during the lifetime of probably every person reading this post, and therefore not really a differentiating feature of Haskell. Nor is lack of ability to create impure functions a feature that can be claimed of Haskell, because that simply isn't true. Haskell's real differentiator in that department is just that you've got to jump through hoops to do it. And if your business rules are inherently impure, then it's not clear to me how a language that tries to ghettoize impurity makes them easier to implement.

by iamdev 13y ago

As someone who has been curious about Haskell, I'm happy to hear someone else say this. The way this article was written feels exactly like the "ruby fever" of 5 years ago.

zwieback 13y ago

Or all the other fevers we've suffered through. Haskell seems like an attractive language but I wish boosters wouldn't advocate their languages as the fix to the problems of large-scale software engineering issues when there's little or no evidence for their claims.

chongli 13y ago
Well, the problem with this is that the evidence is locked up in company trade secrets. A lot of the big commercial users of Haskell are in finance and all their code is under lock and key.
cschneid 13y ago
There was a cool talk on "The Haskell Chat" episode two [1] that goes over how haskell is used in a large team, some members with expert haskell knowledge, some as just technical end-users of the libraries. I found it really interesting to see how a large team can deal with a real haskell project. [1]: http://www.haskellcast.com/episode/002-don-stewart-on-real-world-haskell/ http://www.haskellcast.com/episode/002-don-stewart-on-real-w...

chongli 13y ago

"ruby fever" of 5 years ago The difference is that Haskell is a very principled language. All of the claims and excitement are actually backed up by mathematical proofs. Pure functions really do make your code easier to maintain. And no, it's not the case that Haskell is the only language which allows you to write pure functions. People who try to claim that are being silly and dishonest. Haskell's advantage is that its type system allows you to know at a glance whether or not a function is pure.

tmhedberg 13y ago
While I fully agree that pure code is far easier to maintain than impure code, and the advantages of Haskell are numerous, I think it is a bit strong to state that such claims are backed up by mathematical proofs. Ease of maintenance is a fundamentally subjective claim that cannot be proven, but must be borne out by individual experience (as it has been for you, me, and many others).
- chongli 13y ago
  Ease of maintenance is a fundamentally subjective claim that cannot be proven, but must be borne out by individual experience (as it has been for you, me, and many others). I disagree. You can make objective measurements of maintainability. You can look at cyclomatic complexity and reusability (both wins for pure functions). You can test how often changes lead to bugs and how often the errors are caught. There are many instances of Haskell code where there is only one sensible implementation of a function, given its type. Hell, some Haskell libraries have even been formally verified though admittedly that is done with external packages. I will agree on one thing, though: you do run into trouble when you throw around the word all (or indeed any absolute) without actually meaning it.
  - bunderbunder 13y ago
    > You can look at cyclomatic complexity and reusability (both wins for pure functions). Yes, those are both wins for pure functions. But even there you need an asterisk, because side effects do have their place - the fact of the matter is, the primary task of most real-world software can be summed up as "manipulating mutable state". In light of that I don't think you can necessarily jump from the observation that there are many situations where pure functions are easier to work with than impure ones to the conclusion that pure functions are inherently more maintainable. But even if that were granted for the sake of argument, it's not much of a win for Haskell. The ability to create pure functions is a feature of every language that has been invented during the lifetime of probably every person reading this post, and therefore not really a differentiating feature of Haskell. Nor is lack of ability to create impure functions a feature that can be claimed of Haskell, because that simply isn't true. Haskell's real differentiator in that department is just that you've got to jump through hoops to do it. And if your business rules are inherently impure, then it's not clear to me how a language that tries to ghettoize impurity makes them easier to implement.