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;; Synchronous Clojure trained us to use Exceptions, while asynchronous JavaScript has trained us to use Promises.
;; In contexts where we work asynchronously in Clojure (in particular ClojureScript), it can be difficult to see a definite way of managing failure. Here are some proposals.

;; OPTION 1: adapting exception handling to core.async CSPs
;; As proposed by David Nolen, with some macro sugar we use Exceptions in go blocks with core async in the same way we would do with synchronous code.

(require '[clojure.core.async :as a :refer [go]])

;; defining some helper macros
(defn throw-err "Throw if is error, will be different in ClojureScript"

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(require '[clojure.core.async :as a])

(defn- seq-of-chan "Creates a lazy seq from a core.async channel." [c]
  (lazy-seq
    (let [fst (a/<!! c)]
      (if (nil? fst) nil (cons fst (seq-of-chan c)) ))))

(defn map-pipeline-async "Map for asynchronous functions, backed by clojure.core.async/pipeline-async .

From an asynchronous function af, and a seq coll, creates a lazy seq that is the result of applying the asynchronous function af to each element of coll.

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;; Imagine you have Persons and Dogs entities in you database, with a :dog/master relationship from Dogs to Persons

;; you want a report of how many dog each person in you database has, as a set of [<person-name> <number-of-dogs>], e.g:

#{["John Doe" 3]
  ["Foo bar" 0]
  ["Chuck Norris" 1]}

;; in particular, you want person who do not have a dog to appear in this report.

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(ns utils.keywordize-at-keys
  (:require [clojure.walk :as walk]))
  
(defn- coerced-to-keyword
  [k]
  (when (string? k)
    (keyword k)))


(defn keywordize-at-keys 

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;; # EMULATING DATOMIC EXCISION VIA MANUAL DATA MIGRATION


;; *************************************
;; ## Introduction
;; *************************************

;; This Gist demonstrates a generic way to migrate an entire Datomic database
;; from an existing 'Origin Connection' to a clean 'Destination Connection',
;; while getting rid of some undesirable data and otherwise preserving history.

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import java.io.File
import java.util.*
import java.util.concurrent.atomic.AtomicInteger

data class Coordinate(val x: Int, val y: Int)
data class Point(val label: Int, val coordinate: Coordinate)
data class area(val associatedToPoint: Point, val size: Int = 0)

var seqId = AtomicInteger(1)

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REPLCP

Small dev utility for copying REPL output to the clipboard.

Installation

Via deps.edn, typically in an alias:

{:deps

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(ns bs.utils.mock-connection
  "Utilities for using Datomic"
  (:require [datomic.api :as d])
  (:use clojure.repl clojure.pprint)
  (:import (java.util.concurrent BlockingQueue LinkedBlockingDeque)
           (datomic Connection)))

(defrecord MockConnection
  [dbAtom, ^BlockingQueue txQueue]

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log4j.rootLogger=INFO, syslog

log4j.appender.syslog=org.apache.log4j.net.SyslogAppender
log4j.appender.syslog.Facility=LOCAL7
log4j.appender.syslog.FacilityPrinting=false
log4j.appender.syslog.Header=true
log4j.appender.syslog.SyslogHost=<PAPERTRAIL_HOST>.papertrailapp.com:<PAPERTRAIL_PORT>
log4j.appender.syslog.layout=org.apache.log4j.PatternLayout
log4j.appender.syslog.layout.ConversionPattern==%p: (%F:%L) %x %m %n

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(defn pprint-to-clipboard
  "Copies a pretty-printed representation of value `v` to the clipboard.
  When `v` is not supplied, copies the last REPL output (*1).
  Useful for copying and pasting REPL output to an editor buffer."
  ([]
    (pprint-to-clipboard *1))
  ([v]
   (-> (java.awt.Toolkit/getDefaultToolkit)
     .getSystemClipboard
     (.setContents