Hey guys, I’m looking for a book on design patterns. I found this one: Design Patterns: Elements of Reusable Object-Oriented Software. Of course, it has OO in the title. Is it still useful for a young fledgling clojure dev? What do you guys recommend?

Most of those patterns can be replaced in Clojure with just using a function

So, not that useful imo

really great talk on this topic: https://www.youtube.com/watch?v=E8I19uA-wGY

Can recommend this talk, it got me interested in FP

@c.westrom that book is still pretty useful to understand the patterns, but don't try to do it that way in Clojure. I have it and I refer to it occasionally for my day job using Typescript

@c.westrom I believe SICP Structure and Interpretation of Computer Programs is a classic

Not really a "design patterns" book though... but good for FP if you haven't already read it.

I like to point folks to this http://mishadoff.com/blog/clojure-design-patterns/ when they're asking about "classic" design patterns @c.westrom

This is quite a good preso https://www.infoq.com/presentations/Clojure-Design-Patterns/

I'm getting an error when I modify some code related to a deftype/defprotocol. It works on first load, but after modification, I get:

1. Unhandled java.lang.IllegalArgumentException
   No implementation of method: :as-map of protocol:
   #'com.owoga.tightly-packed-trie.core/ITrie found for class:
   com.owoga.tightly_packed_trie.core.Trie

          core_deftype.clj:  583  clojure.core/-cache-protocol-fn
          core_deftype.clj:  575  clojure.core/-cache-protocol-fn

^ Cancel! Realized I had a defonce instance of the thing I was refactoring... 😳

anyone gone through the web-development-with-clojure book and had problems with chapter 5 replacing cljsbuild with shadow-cljs? Getting kicked hard right now

Hi team, how can I delete maps in vector? for example how can I delete a map if :name is "a" or "c" from given vector want to get

{:name "b" :age 23}

[{:name "a" :age 32} {:name "b" :age 23} {:name "c" :age 23}]

(vec (filter #(contains? #{"a" "c"} (:name %)) [{:name "a"} {:name "b"} {:name "c"}])) @vnazaryan

What’s a simple static file server in clojure? I want to move from local hosting my oz viz to exporting to html and server more widely (to my LAN)

Honestly, for purely local, static stuff, it's hard to beat just typing python -m http.server <port> at the command line in the dir you want to publish. If you don't need to make API calls to a Clojure backend and are just serving static files, that's the route I'd go.

See also:

One really cool thing I like about Clojure's built-in map function is that you can pass it multiple lists. As it maps through, it will take the nth item from each list and pass it to your function:

(def vector-one ["hello " "goodbye "])
(def vector-two ["friend" "buddy"])
(map (partial apply str) vector-one vector-two)
; -> ("hello friend" "goodbye buddy")

(def vector-one ["hello " "goodbye "])
(def vector-two ["friend"])
(map (partial apply str) vector-one vector-two)
; -> ("hello friend" "goodbye friend")

Use an infinite sequence of “friend” for vector-two

map stops when it runs out of a seq input

What's the best way to do this sort of thing (first (for [i items j (expensive-fn i) :when (pred j)] j)) without computing expensive-fn unnecessarily due to chunking? Is there an unchunked version of for?

(imagine there's more layers to the for)

If you want control, use loop recur

In general, if you care about exactly how many things get evaluated, you should not be using lazy seqs

Fair point 🙂

for is just so nice and readable