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Thinking in Types

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Re: Thinking in Types

#21

Post by [deleted] »

mindslight wrote: post #17
platz wrote: post #9

Earlier quoted context omitted.

It's a good question which I think deserves thought, for now I'll just be slightly tongue-in-cheek and link this: http://www.jwz.org/doc/worse-is-better.html

Tongue in cheek? No, it's completely spot-on. People generally learn by forming patterns from many examples, not by studying the patterns themselves. Attempts to directly communicate abstract patterns generally fails (any school anywhere: "this is boring because we are never going to use it"). Programmers are inherently attracted to building on imperfect abstractions, because that brokenness is something to latch on…

[deleted]

Re: Thinking in Types

#22

Post by jarrett »

On a related note: The article (quite reasonably) avoids discussion of the graphics library, but I want to know more about that side of things. I wish graphics got more attention in the Haskell ecosystem in general.

The options right now are pretty dismal. There is quite literally not a single Haskell graphics or GUI package that I've been able to install on OS X. I'd love to use Haskell to build games or desktop GUI apps, but without a library for OpenGL, windowing, etc., it's not practical.

This isn't just whining, though. I bring this up to ask: What can I, as a relatively green Haskell developer, do to improve the situation? Is there a realistic path for a new Haskell user to get involved in the package ecosystem?

I'd be willing to bet that a great many developers like me wanted to try Haskell, but gave up when they found out how many Cabal packages don't compile. I think fixing that would do a lot for Haskell's mainstream acceptance.

Re: Thinking in Types

#23

Post by ephemeralgomi »

spitfire wrote: post #8
woah wrote: post #2

Seeing so much stuff about Haskell lately, but there seems to be a curious dearth of actual software written in it, if it's so great. How is it that janky hacked together languages like JS and PHP have huge numbers of projects built with them, while a supposedly superior language like Haskell is mostly academic? If it really makes you that much faster, where are the apps?

Well, JS is used because it's the only way to run code on a client system. If there were a byte-code available you can bet people would be using other languages. ASM.js exists, and many languages compile to js at the moment. As for PHP, lots of people still eat at McDonalds. I can't explain why.

Partially because McDonalds/PHP lets you eat/deploy by cramming/uploading the food/file directly into your mouth/server. No utensils/tools required.

Re: Thinking in Types

#24

Post by AnimalMuppet »

I'm not sure that this works in more general cases, though.

If I have a more general game with more objects of more types in it, adding each type to the render function is going to get old. In object oriented programming, I'd just call render() on each entry in the list of game objects. But this approach is going to lead me to:

- render each entry in the list of Foo objects

- render each entry in the list of Bar objects

- render each entry in the list of Baz objects

- ...

which doesn't seem to me to work out very well as the game grows more complicated.

(Sorry about all the line breaks - I can't seem to figure out how to get HN to display it right without them.)

Re: Thinking in Types

#25

Post by IsTom »

jarrett wrote: post #20
woah wrote: post #2

Seeing so much stuff about Haskell lately, but there seems to be a curious dearth of actual software written in it, if it's so great. How is it that janky hacked together languages like JS and PHP have huge numbers of projects built with them, while a supposedly superior language like Haskell is mostly academic? If it really makes you that much faster, where are the apps?

I think the package ecosystem is a big barrier. I code on OS X, and it seems like half the Haskell packages I try to install fail to compile. I always get super motivated to do my next project in Haskell, but then give up when I can't install the required libraries. Maybe the situation is better on Linux. In any case, I think Haskell will need reliable package management on at least OS X and Linux before most develop…

It's not that much better on Linux. As a fan of Haskell it makes me sad.

Re: Thinking in Types

#26

Post by tel »

dllthomas wrote: post #18
tel wrote: post #11

Earlier quoted context omitted.

Well, as you go to the next steps you can use proof search techniques to do exactly that: write your types and your programs write themselves as the "only possible implementation". This is already possible sometimes in Haskell so long as we restrict ourselves from pathological values like exceptions and non-termination. In fact, the first place this phrase shows up is Russel O'Connor talking about highly polymorphic…

The first place which phrase shows up?

Mm, I think I went too far there. I was thinking "confession of a Haskell hacker" but got that conflated with "if it types, it's right".

Re: Thinking in Types

#27

Post by gamegoblin »

woah wrote: post #2

Seeing so much stuff about Haskell lately, but there seems to be a curious dearth of actual software written in it, if it's so great. How is it that janky hacked together languages like JS and PHP have huge numbers of projects built with them, while a supposedly superior language like Haskell is mostly academic? If it really makes you that much faster, where are the apps?

Fairly popular tiling window manager: http://en.wikipedia.org/wiki/Xmonad

Re: Thinking in Types

#29

Post by zmoazeni »

AnimalMuppet wrote: post #24

I'm not sure that this works in more general cases, though. If I have a more general game with more objects of more types in it, adding each type to the render function is going to get old. In object oriented programming, I'd just call render() on each entry in the list of game objects. But this approach is going to lead me to: - render each entry in the list of Foo objects - render each entry in the list of Bar obje…

The post links to this page http://www.haskell.org/haskellwiki/Heterogenous_collections and one of other solutions is to use existential types to do it. But the author even said:

However, I don’t think this is a good use case. We can get around this problem in a cleaner and safer way by using the type system rather than subverting it.

Re: Thinking in Types

#30

Post by sgerrand »

jarrett wrote: post #22

On a related note: The article (quite reasonably) avoids discussion of the graphics library, but I want to know more about that side of things. I wish graphics got more attention in the Haskell ecosystem in general. The options right now are pretty dismal. There is quite literally not a single Haskell graphics or GUI package that I've been able to install on OS X. I'd love to use Haskell to build games or desktop GUI…

Have you looked at the Haskell QML bindings? They generally work for cross platform requirements.

http://hackage.haskell.org/package/hsqml-0.1.1/docs/Graphics...

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