bmabey

(ns default-maps
  "Maps with default values, similar to how you can specify default values and blocks to Ruby's Hash.

Examples:

user> (def b (assoc-default {:foo 34 :bar 34} (fn [_ k] (str k))))
#'user/b
user> (get b :foo-bar)
\":foo-bar\"
user> (def m (assoc-default {:foo 34 :bar 34} 343))

john2x

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors and Sequences

favila

(ns favila.async-util
  "Some missing pieces of core.async.

   as-transducer: Make a transducer function easily without Clojure 1.7.
   go-pipe: async/pipe, but returns the go-loop.
   fast-pipeline-blocking: faster than async/pipeline-blocking, but unordered results.
   blocking-consumer: consume a channel with multiple worker threads."
  (:require [clojure.core.async :as async
             :refer [go go-loop <! >! <!! >!! close! take! put! chan]]))

inkrement

#!/bin/bash

OUTDIR=.

while read -r db ; do
  while read -r table ; do

  if [ "$db" == "system" ]; then
     echo "skip system db"
     continue 2;

marwei

Kafka 0.11.0.0 (Confluent 3.3.0) added support to manipulate offsets for a consumer group via cli kafka-consumer-groups command.

1. List the topics to which the group is subscribed

kafka-consumer-groups --bootstrap-server <kafkahost:port> --group <group_id> --describe

Note the values under "CURRENT-OFFSET" and "LOG-END-OFFSET". "CURRENT-OFFSET" is the offset where this consumer group is currently at in each of the partitions.

2. Reset the consumer offset for a topic (preview)

JulienRouse

;Montreal Clojure Meetup 2019


;;sources
; - https://clojure.org/reference/java_interop
; - https://leanpub.com/clojure-java-interop/read_sample
; - http://blog.jayfields.com/2011/12/clojure-java-interop.html
; - https://stackoverflow.com/questions/2181774/calling-clojure-from-java
; - https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.3.2-200

halgari

(ns scratch)

(defn map [f]
  (fn [xf]
    (fn
      ([] (xf))
      ([acc] (xf acc))
      ([acc itm]
       (xf acc (f itm))))))

dvingo

;; inspired by: https://clojuredocs.org/clojure.zip/zipper#example-54d91161e4b081e022073c72

(defn map-zipper
  [m ref-keys]
  {:pre [(set? ref-keys)]}
  (z/zipper
    (fn is-branch? [x]
      (let [ret
            (cond
              (not (coll? x))

travisbrown

The current version of this document is here.

This document contains additional supporting material for the claims in this post (published 1 September 2019), in response to a cease and desist letter from John De Goes that I received on 6 July 2020.

Please see also this post for more information about De Goes deleting the FCoP repository on GitHub shortly before sending the cease and desist letter.

Table of contents

• The complaints
• Response to complaint 1

Vikasg7

(ns cola.core)

(def names ["Sheldon" "Leonard" "Penny" "Rajesh" "Howard"])

(defn double-size [[size name]]
  [(* 2 size) name])

(def group (map vector (repeat 1) names))

(def groups (lazy-cat group (map double-size groups)))