6 ms·

The Evolution of a Haskell Programmer

117 points by hamidr 13y ago

jdn 13y ago
It's quite amusing how accurate this is, knowing Haskell users across a number of these levels. It's quite a handy learning tool as well with the added explanations at the bottom.
b3tta 13y ago
Since the "original" mentioned at the top is not available anymore: http://web.archive.org/web/20071020011113/http://www.cse.ogi.edu/~diatchki/jokes/programmer.html http://web.archive.org/web/20071020011113/http://www.cse.ogi...
agumonkey 13y ago
Was there some new patterns since the last decade (the page updates stopped in 2001) ?
- ocharles 13y ago
  Unifying Recursion Schemes will be part of the ICFP 2013 papers (http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/urs.pdf http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/ur...) which is tangentially related to the penultimate entry using recursion, as we have another way of reasoning about them now.
  - agumonkey 13y ago
    Many thanks
wslh 13y ago
It misses the math Haskell programmer using the closed form expression: http://en.wikipedia.org/wiki/Fibonacci_number#Closed-form_expression http://en.wikipedia.org/wiki/Fibonacci_number#Closed-form_ex... What is the best way to implement it in Haskell since Phi and Psi are real numbers? Edit: as the user tome told me.... It was about the factorial function not about fibonacci. I blindly see fibonacci.
- freyrs3 13y ago
  Naive implementation might be: fib :: Integer -> Integer fib x = truncate $ ( 1 / sqrt 5 ) * ( phi ^ x - psi ^ x ) where phi = ( 1 + sqrt 5 ) / 2 psi = ( 1 - sqrt 5 ) / 2
  - fhars 13y ago
    Alas, that version is only correct up to x = 25, because *Main> 1 / sqrt 5 * (((1 + sqrt 5) / 2) ^ 26 - ((1 - sqrt 5) / 2) ^ 26) 121392.99999999999 happens to be just on the wrong side of the truncate.
- tome 13y ago
  That's not a Haskell question per se, but in any language you can implement it using two intergers (a, b) that represent the number a + b * sqrt(5).
  - wslh 13y ago
    Yes, it is a Haskell question more than you think ;-) since, for example, using types for fraction or other kind of patterns can work different in Haskell than in other languages. I think it's possible in Haskell to add symbolic manipulation as well like in http://christopherolah.wordpress.com/2012/06/01/hasksymb-an-experiment-in-haskell-symbolic-algebra/ http://christopherolah.wordpress.com/2012/06/01/hasksymb-an-... or http://homepages.inf.ed.ac.uk/wadler/realworld/docon2.html http://homepages.inf.ed.ac.uk/wadler/realworld/docon2.html Also, there are implementations in the list that can be implemented in the same way on non functional languages.
    - tome 13y ago
      I think it would be neater doing it in Haskell than, say Java, but the fundamental idea would be the same in both.
- FreeFull 13y ago
  But this is all about the factorial function, not the fibonacci sequence
wreckimnaked 13y ago
I really want to understand about morphisms and category theory after reading this. Can anyone point out any good introduction to the category theory behind those catamorphisms?
- sfvisser 13y ago
  More of a programming than a CT introduction, but very useful nonetheless: Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire (1991), by Erik Meijer, Maarten Fokkinga, Ross Paterson
- Toshio 13y ago
  These slides may be of some help. http://yogsototh.github.com/Category-Theory-Presentation http://yogsototh.github.com/Category-Theory-Presentation
- gtani 13y ago
  here's some course materials http://www.cse.chalmers.se/edu/course/afp/lectures.html http://www.cse.chalmers.se/edu/course/afp/lectures.html http://www.scs.stanford.edu/11au-cs240h/notes/ http://www.scs.stanford.edu/11au-cs240h/notes/ http://www.seas.upenn.edu/~cis194/lectures.html http://www.seas.upenn.edu/~cis194/lectures.html
davidp 13y ago
I am simultaneously intrigued by the possibilities of functional programming, and horrified by the ways it can take people off into the weeds. Were I to use Haskell in a real-world project with teammates, I'd have to keep an iron grip on the complexity of the code the team writes. Maintainability (mainly readability/comprehensibility as far as I'm concerned) is far more important for the kind of work I do than theoretical purity and hypothetical applicability to classes of problems the team isn't facing. I could easily keep things on the rails on my own, but I suppose it's simply unsettling thinking about using Haskell for something sizable; probably due to my own lack of experience with it. I'd love to hear about sizable real-world Haskell projects, since I think FP is the future of software engineering.
- mwcampbell 13y ago
  Your concerns resonate with me. I think in most cases, particularly in commercial software development, we should value clarity, familiarity, and maintainability over cleverness, expressiveness, and terseness. I think that like Haskell, Scala's flexibility tends to take some people off into the weeds. See, for example, Coda Hale's concerns about using Scala at Yammer, from about 2 years ago: http://codahale.com/downloads/email-to-donald.txt http://codahale.com/downloads/email-to-donald.txt However, I think we need to be careful not to overvalue familiarity. Rich Hickey's talk "Simple Made Easy" is well-known, and I think he's correct to tell us that we should value simplicity over ease. I guess the answer is to use functional programming to make our software simpler, and not let cleverness take us off into the weeds.
- gtani 13y ago
  Most of these aren't detailed but it's a start. FP complete is a startup devoted to bringing haskell into more production systems http://www.joachim-breitner.de/blog/archives/606-Real-World-Haskell-Applications%20.html http://www.joachim-breitner.de/blog/archives/606-Real-World-... http://corp.galois.com/systems-software http://corp.galois.com/systems-software http://www.haskell.org/haskellwiki/Haskell_in_industry http://www.haskell.org/haskellwiki/Haskell_in_industry http://cufp.org/conference/schedule/2012 http://cufp.org/conference/schedule/2012 https://www.fpcomplete.com/business/resources/case-studies https://www.fpcomplete.com/business/resources/case-studies _____________ similar for scala http://typesafe.com/company/casestudies http://typesafe.com/company/casestudies
ExpiredLink 13y ago
Haskell? Just let it fade away!
- Peaker 13y ago
  Ironically, Haskell is gaining traction while your comment is fading away :-)

117 points by hamidr 13y ago

jdn 13y ago

It's quite amusing how accurate this is, knowing Haskell users across a number of these levels. It's quite a handy learning tool as well with the added explanations at the bottom.

b3tta 13y ago

Since the "original" mentioned at the top is not available anymore: http://web.archive.org/web/20071020011113/http://www.cse.ogi.edu/~diatchki/jokes/programmer.html http://web.archive.org/web/20071020011113/http://www.cse.ogi...

agumonkey 13y ago

Was there some new patterns since the last decade (the page updates stopped in 2001) ?

ocharles 13y ago
Unifying Recursion Schemes will be part of the ICFP 2013 papers (http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/urs.pdf http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/ur...) which is tangentially related to the penultimate entry using recursion, as we have another way of reasoning about them now.
- agumonkey 13y ago
  Many thanks

wslh 13y ago

It misses the math Haskell programmer using the closed form expression: http://en.wikipedia.org/wiki/Fibonacci_number#Closed-form_expression http://en.wikipedia.org/wiki/Fibonacci_number#Closed-form_ex... What is the best way to implement it in Haskell since Phi and Psi are real numbers? Edit: as the user tome told me.... It was about the factorial function not about fibonacci. I blindly see fibonacci.

freyrs3 13y ago
Naive implementation might be: fib :: Integer -> Integer fib x = truncate $ ( 1 / sqrt 5 ) * ( phi ^ x - psi ^ x ) where phi = ( 1 + sqrt 5 ) / 2 psi = ( 1 - sqrt 5 ) / 2
- fhars 13y ago
  Alas, that version is only correct up to x = 25, because *Main> 1 / sqrt 5 * (((1 + sqrt 5) / 2) ^ 26 - ((1 - sqrt 5) / 2) ^ 26) 121392.99999999999 happens to be just on the wrong side of the truncate.
tome 13y ago
That's not a Haskell question per se, but in any language you can implement it using two intergers (a, b) that represent the number a + b * sqrt(5).
- wslh 13y ago
  Yes, it is a Haskell question more than you think ;-) since, for example, using types for fraction or other kind of patterns can work different in Haskell than in other languages. I think it's possible in Haskell to add symbolic manipulation as well like in http://christopherolah.wordpress.com/2012/06/01/hasksymb-an-experiment-in-haskell-symbolic-algebra/ http://christopherolah.wordpress.com/2012/06/01/hasksymb-an-... or http://homepages.inf.ed.ac.uk/wadler/realworld/docon2.html http://homepages.inf.ed.ac.uk/wadler/realworld/docon2.html Also, there are implementations in the list that can be implemented in the same way on non functional languages.
  - tome 13y ago
    I think it would be neater doing it in Haskell than, say Java, but the fundamental idea would be the same in both.
FreeFull 13y ago
But this is all about the factorial function, not the fibonacci sequence

wreckimnaked 13y ago

I really want to understand about morphisms and category theory after reading this. Can anyone point out any good introduction to the category theory behind those catamorphisms?

sfvisser 13y ago
More of a programming than a CT introduction, but very useful nonetheless: Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire (1991), by Erik Meijer, Maarten Fokkinga, Ross Paterson
Toshio 13y ago
These slides may be of some help. http://yogsototh.github.com/Category-Theory-Presentation http://yogsototh.github.com/Category-Theory-Presentation
gtani 13y ago
here's some course materials http://www.cse.chalmers.se/edu/course/afp/lectures.html http://www.cse.chalmers.se/edu/course/afp/lectures.html http://www.scs.stanford.edu/11au-cs240h/notes/ http://www.scs.stanford.edu/11au-cs240h/notes/ http://www.seas.upenn.edu/~cis194/lectures.html http://www.seas.upenn.edu/~cis194/lectures.html

davidp 13y ago

I am simultaneously intrigued by the possibilities of functional programming, and horrified by the ways it can take people off into the weeds. Were I to use Haskell in a real-world project with teammates, I'd have to keep an iron grip on the complexity of the code the team writes. Maintainability (mainly readability/comprehensibility as far as I'm concerned) is far more important for the kind of work I do than theoretical purity and hypothetical applicability to classes of problems the team isn't facing. I could easily keep things on the rails on my own, but I suppose it's simply unsettling thinking about using Haskell for something sizable; probably due to my own lack of experience with it. I'd love to hear about sizable real-world Haskell projects, since I think FP is the future of software engineering.

mwcampbell 13y ago
Your concerns resonate with me. I think in most cases, particularly in commercial software development, we should value clarity, familiarity, and maintainability over cleverness, expressiveness, and terseness. I think that like Haskell, Scala's flexibility tends to take some people off into the weeds. See, for example, Coda Hale's concerns about using Scala at Yammer, from about 2 years ago: http://codahale.com/downloads/email-to-donald.txt http://codahale.com/downloads/email-to-donald.txt However, I think we need to be careful not to overvalue familiarity. Rich Hickey's talk "Simple Made Easy" is well-known, and I think he's correct to tell us that we should value simplicity over ease. I guess the answer is to use functional programming to make our software simpler, and not let cleverness take us off into the weeds.
gtani 13y ago
Most of these aren't detailed but it's a start. FP complete is a startup devoted to bringing haskell into more production systems http://www.joachim-breitner.de/blog/archives/606-Real-World-Haskell-Applications%20.html http://www.joachim-breitner.de/blog/archives/606-Real-World-... http://corp.galois.com/systems-software http://corp.galois.com/systems-software http://www.haskell.org/haskellwiki/Haskell_in_industry http://www.haskell.org/haskellwiki/Haskell_in_industry http://cufp.org/conference/schedule/2012 http://cufp.org/conference/schedule/2012 https://www.fpcomplete.com/business/resources/case-studies https://www.fpcomplete.com/business/resources/case-studies _____________ similar for scala http://typesafe.com/company/casestudies http://typesafe.com/company/casestudies

ExpiredLink 13y ago

Haskell? Just let it fade away!

Peaker 13y ago
Ironically, Haskell is gaining traction while your comment is fading away :-)