John Wiegley: Putting Lenses to Work

John Wiegley: Putting Lenses to Work

Putting Lenses to Work

and you can learn enough lens to be productive in 1 hours with this talk without reading docs at all. You can skip the theory and go straight to usage: link to this video

As with anything Haskell, one could simply reply with "here's the formal definition." But in easily digestible terms, it's a way to narrow your view over a collection to a subset that satisfies some property, and perhaps perform some operations on that subset. This video presentation (with a very humorous audience dynamic, might I add) serves as a great introduction by example: link to this video

Good examples in "Putting lenses to work" by John Weigley: link to this video Then for a great book that gives a great understanding see Chris Penner's amazing and fun "Optics by example: link

> Lenses let you do some amazing things, but I think most of their existence is just thanks to how truly horrible (nested) record field access and updates were. Only for the most basic uses. Architecting programs as folds or traversals can be powerful. One simple example of lenses i can think of being useful for more than record access is: > sumOf (folded . folded) Just 1, Just 2 3 More are in this presentation: link to this video

Definitely agree on lenses being one of the more mind blowing things I've encountered and eventually grokked in programming. I would also recommend link to this video as a good video on lenses in part because the latter portion has some pretty far-out examples of that deep well you mentioned.

I probably should've mentioned that most of the work we've been doing so far is definitely not "big data" and mostly involves running NLP processes over streams of data. We've found for our work, for example, chatter fairly useful, but mostly we've been working on our own approaches and found the library ecosystem very helpful in building the pipeline and infrastructure that powers our applications and the language itself helpful for implementing our own algorithms. For example we've found streaming in combination with foldl to be amazing for implementing pretty much any streaming algorithm you want in such a manner that the code is simultaneously straightforward and easy to understand whi…