

The Point of Laziness (2011) - amelius
https://existentialtype.wordpress.com/2011/04/24/the-real-point-of-laziness/

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serve_yay
I can't understand anything written in this blog very well, but it was fun to
try! (I don't mean this post, I mean the blog) Seems like good stuff if you
know what the author is talking about.

~~~
lambdasquirrel
My PL friends tell me he has a reputation for being a little bit of a troll
(and the content of this post is likewise), but if you meet him in person,
it's hard to dislike him. It's frustrating talking to him because there's a
grain of truth to what he says.

For example, that laziness makes parallelism harder. I mean, cmon, the _last_
thing I'm worrying about is whether the thread is going to evaluate its
results to weak-head-normal-form.

So yea, mostly, he confuses people who aren't familiar with the material. ;)

~~~
tel
From reading Harper's works and also listening to his lectures (but not
meeting the guy, sadly) I'd back that up. He's more than happy to say
something that's both insightful and... inciting! In a lot of communities this
rallies the troops to descend upon what he's written and strip mine it for
goodies while aggressively discarding the rhetoric—clearly a useful tactic.

But in other communities it feels really trollish and oversimplified. It's the
equivalence of [https://xkcd.com/793/](https://xkcd.com/793/).

Like physicists, though, he's got some phenomenally great points which most
"practitioners" happily ignore all while eating the possibly enormous
consequences. So if you can spend the time to figure out where he's coming
from then you can really gain _a lot_.

~~~
_delirium
Once I've gotten used to his style, I agree, the content is almost invariably
very good and well thought out. I tend to now just mentally rewrite his
insistence that certain things are "wrong" or "idiotic" or "useless", to a
statement along the lines of, "X is widely believed, but I would like to point
out some of its disadvantages, and advantages of a different view". Since to
some extent he's in the position of an ML holdout, in a PLs field where the
Haskell researchers are lopsidedly larger than the once-larger set of ML
researchers, and Haskell is often seen as the current theoretically advanced
language (while ML was the theoretically advanced language of the '80s/'90s),
it's useful to have a strong advocate for the minority view that ML was on the
better track.

edit: On the subject here, the response he links at the bottom is also
interesting. In the first comment, Harper even acknowledges one thing he
actually does like in Haskell more than ML:
[http://augustss.blogspot.com/2011/05/more-points-for-lazy-
ev...](http://augustss.blogspot.com/2011/05/more-points-for-lazy-evaluation-
in.html)

~~~
tel
> it's useful to have a strong advocate for the minority view that ML was on
> the better track.

Total agreement here. I also really enjoy his rather principled, HoTT-inspired
perspective on type theory. I vastly prefer PFPL to Pierce's TaPL due to PFPL
just being less preoccupied with the diversity of reasoning possible and more
interested in explaining the "one right way" efficiently.

------
jonsterling
<3 bob harper

