Learning Haskell makes you a better programmer?

[Phil Lavoie]

I have learned Haskell during my bachelor's degree and I cannot 
say it has made a big difference for me, although I do understand 
why people like the concepts of it. Recently, I was suggested by 
a professor to re-learn it. He suggested me so because I was 
making a presentation on how to extend the standard library of my 
university's pet language NIT, which is pure object oriented. 
Apparently, he thought that my additions were influenced by the 
functional paradigm.

Therefore, following his suggestion, I re-learned Haskell and 
tried to implement my master's project in it, to sort of test it 
out.

I was pleased because Haskell:
-Emphasizes more on formalism than actual machine code algorithms
-Abstract much of the machine oriented concepts in the favor of 
more mathemathical ones
-The resulting code CAN BE much, much more lightweight

I was displeased because:
-When it comes to IO, you have to work harder, and IO it is for 
real world applications
-IO and mutable states also include a whole bunch of complicated 
data structures /algorithms which are just a pain to implement in 
Haskell compared to machine oriented languages

So I just abandoned the idea (I used complicated data 
structures). I think what Bearophile said sums it up the best: 
It's really a matter of what is the problem you and how you are 
planning to solve it. Sometimes a paradigm fits best, sometimes 
its a burden. Sometimes a language is better, sometimes it isn't.

Most of the times, I find extensions of procedural languages to 
be the best answers. And this is why I love D. Power, 
flexibility, support for A LOT of paradigms with the right amount 
of compromises. Describing the language features and comparing it 
to others just don't show how great it is. D starts to shine when 
you actually program something complicated in it.

Often, when using D, I found myself thinking: "Oh! I can do that, 
sweet!", rather than: "Oh! I can't do that, right... So how to I 
workaround it...". Some people think that the "working around it" 
is the true benefit of functional languages, and there are times 
when they are right, and there are times when they aren't.

In conclusion I'd say that yeah, maybe Haskell can make you a 
better programmer, but maybe it won't change a thing. 
Incorporating many concepts and paradigms and knowing when which 
is best, that is the true challenge: not being forced to use one 
for everything. So maybe Haskell will help you understand 
functional paradigm, and that is what's great about it. But, 
IMHO, when you construct a huge software using multiple 
inputs/outputs/data structures/arcane algorithms/..., the 
functional paradigm might get in your way...