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Haskell is extremely complex, and that’s the point: to isolate complexity at the language level, where safe patterns can be researched, developed, and then scal

Haskell is extremely complex, and that’s the point: to isolate complexity at the language level, where safe patterns can be researched, developed, and then scaled out to arbitrary applications. Please call this “Towards a simple Haskell web stack” or something else less oxymoronic.

bojo 7y ago
I am going to disagree with this simply because it's talking about the stack, not the language. As a Haskell developer who uses a much more complex stack than provided in the article, and seen too many "there aren't enough basic Haskell web stack tutorials!" posts here and there, I would say the library choices here fit that bill perfectly. That said, once the adventerous non-Haskell user builds a basic application using this stack, they will then run into the brick wall of using a language which you are calling "complex", I would argue "different", and realizing there are a lot of new things they need to learn to actually be productive in it.
agentultra 7y ago
> Haskell is extremely complex I extremely disagree. I think C++ is extremely complex. Haskell is simple by comparison [0]. Once you understand enough Haskell to write basic programs in it this stack is roughly similar in scope to a Ruby + Sinatra or Python + Flask web application. [0] https://www.youtube.com/watch?v=PNRju6_yn3o https://www.youtube.com/watch?v=PNRju6_yn3o
- seagreen 7y ago
  It depends on what we mean by Haskell. If we mean "Haskell the latest specification" that's Haskell 2010. I suppose we could think of it as pretty simple, though lazy evaluation means that any implementation of it is going to be complicated. However I don't know of a single company that uses plain Haskell 2010. They all use GHC (or more complex tools like GHCJS!) and GHC Haskell is a beast: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html https://downloads.haskell.org/~ghc/latest/docs/html/users_gu...
  - lalaithion 7y ago
    And how many companies use a C++ standard? GCC and Clang both provide a large number of extensions. https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C-Extensions.html#C-Extensions https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C-Extensions.ht... https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C_002b_002b-Extensions.html#C_002b_002b-Extensions https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C_002b_002b-Ext...
    - seagreen 7y ago
      OP: haskell is extremely complex. Responder: not it's not (eg C++ is more complex) Me: actually haskell is a complex, beastly language, eg check out the language extensions You: but C++ is more complex! Me: i agree EDIT: Didn't mean to sound snarky, the discussion has just gotten really layered and I wanted to explain my position.
  - agentultra 7y ago
    Fair enough there are some combinations of compiler extensions that don't interact well and I've written enough type level code to know which ones to stay away from. The C++ move semantics are standard though and have lots of unintended consequences to make easy-to-describe constructors incredibly difficult to implement in practice. My point was that saying Haskell is extremely complex is not technically correct. It's a qualitative statement and disingenuous. Complex relative to what? The stack the OP is presenting is relatively simple in the Haskell space. It's not inherently complex by virtue of being written in Haskell.
    - seagreen 7y ago
      > It's a qualitative statement and disingenuous. Complex relative to what? Complex relative to most programming languages. C++ is more complex. That says very little. C++ is an extreme outlier. I think Haskellers do a disservice to people they're trying to convince to do haskell by saying it's not complex. Haskell has a zillion extensions and crazy features, most of which show up in at least some popular Hackage libraries. Arrow syntax! Type families! Data kinds! Pattern synonyms! View patterns! Existential types! Rank-N types! The list goes on and on. PS: I think Haskell is awesome and one of the best languages out there. I've written a pretty decent amount of FOSS haskell stuff. Complex doesn't mean bad. EDIT: The complexity doesn't come just through language extensions. The process GHC goes through to produce fast code is crazy too. It works, but it's not simple.
- Symmetry 7y ago
  I entirely agree about the language itself being a comfortable middle weight, somewhere around the order of Python. But both languages give you a lot of scope to make things complicated and there are much stronger norms against making code as clever as possible in Python than in Haskell. Is there a Pythonic Haskell movement? Because if there isn't there should be.
  - weavie 7y ago
    There is this great talk 'stick to simple Haskell' along those lines, but unfortunately it is hosted here https://skillsmatter.com/skillscasts/14133-stick-to-simple-haskell https://skillsmatter.com/skillscasts/14133-stick-to-simple-h... Unfortunately I can't find it anywhere else, but it is worth keeping your ears out in case it pops up somewhere..
    - behnamoh 7y ago
      The link doesn't work.
      - weavie 7y ago
        Yeah, sadly skillsmatter have gone bust so all their content has disappeared. Its a huge shame as there was so much good stuff there. I really hope it will resurface soon..
leshow 7y ago
Haskell 2010 isn't that complex. It's sum and product types and typeclasses, essentially. The many language extensions, depending on what you use, can make for something extremely complex, but you also don't have to do much more than enable them in many situations if you're just a user of a library.

bojo 7y ago

I am going to disagree with this simply because it's talking about the stack, not the language. As a Haskell developer who uses a much more complex stack than provided in the article, and seen too many "there aren't enough basic Haskell web stack tutorials!" posts here and there, I would say the library choices here fit that bill perfectly. That said, once the adventerous non-Haskell user builds a basic application using this stack, they will then run into the brick wall of using a language which you are calling "complex", I would argue "different", and realizing there are a lot of new things they need to learn to actually be productive in it.

agentultra 7y ago

> Haskell is extremely complex I extremely disagree. I think C++ is extremely complex. Haskell is simple by comparison [0]. Once you understand enough Haskell to write basic programs in it this stack is roughly similar in scope to a Ruby + Sinatra or Python + Flask web application. [0] https://www.youtube.com/watch?v=PNRju6_yn3o https://www.youtube.com/watch?v=PNRju6_yn3o

seagreen 7y ago
It depends on what we mean by Haskell. If we mean "Haskell the latest specification" that's Haskell 2010. I suppose we could think of it as pretty simple, though lazy evaluation means that any implementation of it is going to be complicated. However I don't know of a single company that uses plain Haskell 2010. They all use GHC (or more complex tools like GHCJS!) and GHC Haskell is a beast: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html https://downloads.haskell.org/~ghc/latest/docs/html/users_gu...
- lalaithion 7y ago
  And how many companies use a C++ standard? GCC and Clang both provide a large number of extensions. https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C-Extensions.html#C-Extensions https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C-Extensions.ht... https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C_002b_002b-Extensions.html#C_002b_002b-Extensions https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/C_002b_002b-Ext...
  - seagreen 7y ago
    OP: haskell is extremely complex. Responder: not it's not (eg C++ is more complex) Me: actually haskell is a complex, beastly language, eg check out the language extensions You: but C++ is more complex! Me: i agree EDIT: Didn't mean to sound snarky, the discussion has just gotten really layered and I wanted to explain my position.
- agentultra 7y ago
  Fair enough there are some combinations of compiler extensions that don't interact well and I've written enough type level code to know which ones to stay away from. The C++ move semantics are standard though and have lots of unintended consequences to make easy-to-describe constructors incredibly difficult to implement in practice. My point was that saying Haskell is extremely complex is not technically correct. It's a qualitative statement and disingenuous. Complex relative to what? The stack the OP is presenting is relatively simple in the Haskell space. It's not inherently complex by virtue of being written in Haskell.
  - seagreen 7y ago
    > It's a qualitative statement and disingenuous. Complex relative to what? Complex relative to most programming languages. C++ is more complex. That says very little. C++ is an extreme outlier. I think Haskellers do a disservice to people they're trying to convince to do haskell by saying it's not complex. Haskell has a zillion extensions and crazy features, most of which show up in at least some popular Hackage libraries. Arrow syntax! Type families! Data kinds! Pattern synonyms! View patterns! Existential types! Rank-N types! The list goes on and on. PS: I think Haskell is awesome and one of the best languages out there. I've written a pretty decent amount of FOSS haskell stuff. Complex doesn't mean bad. EDIT: The complexity doesn't come just through language extensions. The process GHC goes through to produce fast code is crazy too. It works, but it's not simple.
Symmetry 7y ago
I entirely agree about the language itself being a comfortable middle weight, somewhere around the order of Python. But both languages give you a lot of scope to make things complicated and there are much stronger norms against making code as clever as possible in Python than in Haskell. Is there a Pythonic Haskell movement? Because if there isn't there should be.
- weavie 7y ago
  There is this great talk 'stick to simple Haskell' along those lines, but unfortunately it is hosted here https://skillsmatter.com/skillscasts/14133-stick-to-simple-haskell https://skillsmatter.com/skillscasts/14133-stick-to-simple-h... Unfortunately I can't find it anywhere else, but it is worth keeping your ears out in case it pops up somewhere..
  - behnamoh 7y ago
    The link doesn't work.
    - weavie 7y ago
      Yeah, sadly skillsmatter have gone bust so all their content has disappeared. Its a huge shame as there was so much good stuff there. I really hope it will resurface soon..

leshow 7y ago

Haskell 2010 isn't that complex. It's sum and product types and typeclasses, essentially. The many language extensions, depending on what you use, can make for something extremely complex, but you also don't have to do much more than enable them in many situations if you're just a user of a library.