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How we secretly introduced Haskell and got away with it

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Re: How we secretly introduced Haskell and got away with it

#111

Post by seagreen »

slezakattack wrote: post #107
xyzzy4 wrote: post #73

Haskell is a bad language, in my opinion, because you can't tell what the O(n) run-time is for any operation. Instead you just have to "trust" that it'll be fast enough. More on this: https://www.reddit.com/r/haskell/comments/1f48dc/what_does_t... All of the answers seem insufficient. Basically you can't estimate Haskell run-time unless you are very familiar with the internal Haskell engine.

Completely untrue. I'm not a Haskell evangelist (I appreciate it for what it is) but I thought I would at the very least point out that most of the documentation for basic data structures (i.e. Data.List[1]) not only are well-documented but have a link on the far-right side of the documentation site that directly shows you the source code and it's usually easy to tell what it's doing. Any developer should be able to…

I think he's talking about how it can be hard to tell what's already been evaluated and what hasn't.

Re: How we secretly introduced Haskell and got away with it

#112

Post by cmrdporcupine »

z3t4 wrote: post #29
DigitalJack wrote: post #22

Earlier quoted context omitted.

There is another aspect. Changing languages. Rewriting in a language that is sufficiently different from the original forces you to look at the problem with new eyes. You effectively have greater mental coverage of the problem domain.

Articles like: We switched from language X to language Y with the conclusion that language Y is better smile My favorite is when they make another post half a year later saying they changed from Y to Z. It seems that following the trend and using the latest and greatest tools doesn't necessary mean the new tools are better, but that you got to rewrite your applications from scratch, with much more knowledge about the…

And they inevitably fail to mention the pissed-off product or QA manager or customer who realizes their favourite feature or corner case or bugfix is missing from the rewritten version because the developer didn't understand or notice that aspect of the original.

Re: How we secretly introduced Haskell and got away with it

#113

Post by prodigal_erik »

cmrdporcupine wrote: post #112
z3t4 wrote: post #29

Earlier quoted context omitted.

Articles like: We switched from language X to language Y with the conclusion that language Y is better smile My favorite is when they make another post half a year later saying they changed from Y to Z. It seems that following the trend and using the latest and greatest tools doesn't necessary mean the new tools are better, but that you got to rewrite your applications from scratch, with much more knowledge about the…

And they inevitably fail to mention the pissed-off product or QA manager or customer who realizes their favourite feature or corner case or bugfix is missing from the rewritten version because the developer didn't understand or notice that aspect of the original.

> It hardly seems worth even having a bug system if the frequency of from-scratch rewrites always outstrips the pace of bug fixing. Why not be honest and resign yourself to the fact that version 0.8 is followed by version 0.8, which is then followed by version 0.8?

Re: How we secretly introduced Haskell and got away with it

#114

Post by the_af »

snowcrshd wrote: post #89
chowells wrote: post #68

Earlier quoted context omitted.

I can't imagine using a haskell-like language without laziness. It's what makes it possible to actually write small reusable functions. Tell me, have you ever used foldr in Purescript? It just doesn't lead to reusable logic there, so I have no idea why you would. But in Haskell, foldr is used everywhere. Laziness means that logic built with it is actually reusable.

> I can't imagine using a haskell-like language without laziness. It's what makes it possible to actually write small reusable functions. I don't understand your point. Why is laziness a requirement to write small reusable functions? Are you thinking about currying? OCaml is (relatively) similar to Haskell and is not lazy. Function currying does not require laziness.

It's unrelated to currying.

It's also hard to explain, but if you're used to Haskell, working with an eager-by-default language such as OCaml or ML is mildly annoying. You can adapt, of course, but it does seem as if gluing stuff together is trickier with eager evaluation.

There are downsides to lazy-by-default, of course.

Re: How we secretly introduced Haskell and got away with it

#115

Post by astrobe_ »

slezakattack wrote: post #107
xyzzy4 wrote: post #73

Haskell is a bad language, in my opinion, because you can't tell what the O(n) run-time is for any operation. Instead you just have to "trust" that it'll be fast enough. More on this: https://www.reddit.com/r/haskell/comments/1f48dc/what_does_t... All of the answers seem insufficient. Basically you can't estimate Haskell run-time unless you are very familiar with the internal Haskell engine.

Completely untrue. I'm not a Haskell evangelist (I appreciate it for what it is) but I thought I would at the very least point out that most of the documentation for basic data structures (i.e. Data.List[1]) not only are well-documented but have a link on the far-right side of the documentation site that directly shows you the source code and it's usually easy to tell what it's doing. Any developer should be able to…

I'm not a C evangelist, but I would point out that most documentation of standard C function is very detailed and its code is shown in its man page. Any developer should be able to grok that code and determine its safety. Mattaku...

Re: How we secretly introduced Haskell and got away with it

#116

Post by framp »

Glad to see Haskell used in production.

It's kind of funny that build reproducibility (which was a major issue before stack) is one of the strong point.

I wonder if, for your project, using cloudhaskell would have been more appropriate. I have a feeling some of the problems you found could have been solved with that.

Re: How we secretly introduced Haskell and got away with it

#117

Post by Ruud-v-A »

mybrid wrote: post #6

In the 1990s I did research on the efficacy claims of object oriented programming versus procedural programming. This article bares a striking resemblance in the claims. Case study after case study showed that object oriented code had less bugs due to compilers catching bugs, etc. However, almost every study was similar to this report: it was a re-write from procedural to object-oriented. There exists strong evidence…

To be clear, our new application is better (faster, scales better, more maintainable), for the most part because of the improved architecture.

As we were going to do the rewrite anyway, we considered more alternatives than just Python. For programs that have to be reliable and maintainable, I prefer a language with a strong static type system. Haskell has that, and it has a few practical benefits over other tools that made it an excellent choice for our use case.

Re: How we secretly introduced Haskell and got away with it

#119

Post by purescript »

chowells wrote: post #68
daxfohl wrote: post #38

I'm just starting with Haskell and PureScript. So far I'm liking the latter better. It solves a few of their gripes with respect to strings, laziness and records, plus has a more granular/extendable effects system and cleans up the standard typeclass hierarchy. Also `head []` doesn't crash. Of course Haskell is more mature, has support for multithreading and STM, compiles to native, so it's more performant. But PureS…

I can't imagine using a haskell-like language without laziness. It's what makes it possible to actually write small reusable functions. Tell me, have you ever used foldr in Purescript? It just doesn't lead to reusable logic there, so I have no idea why you would. But in Haskell, foldr is used everywhere. Laziness means that logic built with it is actually reusable.

Here is foldl implemented using foldr in PureScript, along with an example of using laziness to gain modularity:

http://try.purescript.org/?gist=63d81adf9f5257ffa4f576df2658...

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