Squiggly Lines: Background lint- and type-checking for Clojure in emacs.

In the alternate universe where I am very honest, my résumé contains a line item for the aggregate year I've spent fiddling with init.el. It does not, however, list emacs lisp among the languages I know, because (in this alternate universe) I have too much self respect to flaunt cut and paste skills.

In the present universe, this is going to be awkward, because I will have to present really crappy elisp code without apology.

What this is about.

  1. One of the things you get in an industrial strength IDE, in exchange for giving up your favorite editor ...
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NYC Clojure Meetup slides on lenses and appropriate typing

To everyone who attended yesterday's NYC Clojure Meetup: thanks for listening to me, asking good questions and providing some pretty great answers as well.

Here are the slides. For more detail on nearly everything, see previous posts.

(Navigate using the compass arrows. Up/Down within a section; Left/Right betwen sections; ESC for overview.)

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Type-safe transducers in Clojure. And Scala. And Haskell.

TL;DR

  1. As noted earlier, transducers can be properly annotated in Clojure using core.typed and they probably should be.
  2. But... there are a few tricks necessary to make it work.
  3. Transducers in Scala require tricks too, but different ones.
  4. Oh, but they're so lovely in Haskell.

Update 2015-01-12

Were you led here by Clojure Gazette? Eric Normand is usually more discriminating, but don't worry, this will only waste a little of your time. Per the previous batch of updates, just below, and various subsequent posts on more or less the same topic, it should be clear this ...

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vanholes - Van Laarhoven Lenses in Clojure

In two previous posts, I went on about lenses in Clojure. Pinholes comprised a small library of higher order functions to formalize and simplify the viewing and manipulation of complex nested structures. Tinholes did essentially the same thing, but with macros instead. In both cases, there's recursion going on, as we burrow through layers of nesting, but macros had the advantage of doing it all before compilation, giving core.typed a chance to check our work.

The macro post was inexplicably popular, catapulting me to levels of fame I never expected to achieve without consciously emulating an early De ...

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tinholes - performant, strongly typed lenses in Clojure

In a previous post, I built up a framework for lens-like constructs in Clojure: essentially some fancified versions of assoc-in and get-in to allow for bidirectional transformations along the nesting path and some utilities to generate special-purpose getter/setter functions. The name, "pinhole," is supposed to suggest a more primitive, utilitarian mechanism for achieving focus.

While still ruing (sort of) other mistakes, I found myself worrying that a triumphal sentence near the end of the piece

What's more, thanks to the expressive power of dynamic Clojure,
and higher order functions, these lenses are not just simple to
use but ...
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Typecasting, part 2

Some time after my recent fiddles with IMDB, I read an interesting article about using a perceptron to classify words as parts of speech based on features that precede them in text. It's all done in python or some such sh*t, but whatever. Still very cool. Since I had all of this IMDB data accumulated in Mongo, I thought I would try to play with it, and the idea I had was to predict metacritic scores from the actors that appeared in each film. In retrospect, it's far from clear that such a prediction can be made ...

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