Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.
A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.
val square : Int => Int = x => x * x
| #!/usr/bin/env bash | |
| set -Eeuo pipefail | |
| trap cleanup SIGINT SIGTERM ERR EXIT | |
| script_dir=$(cd "$(dirname "${BASH_SOURCE[0]}")" &>/dev/null && pwd -P) | |
| usage() { | |
| cat <<EOF | |
| Usage: $(basename "${BASH_SOURCE[0]}") [-h] [-v] [-f] -p param_value arg1 [arg2...] |
This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.
The script is here:
#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"
I'm going to do something that I don't normally do, which is to say I'm going to talk about comparative benchmarks. In general, I try to confine performance discussion to absolute metrics as much as possible, or comparisons to other well-defined neutral reference points. This is precisely why Cats Effect's readme mentions a comparison to a fixed thread pool, rather doing comparisons with other asynchronous runtimes like Akka or ZIO. Comparisons in general devolve very quickly into emotional marketing.
But, just once, today we're going to talk about the emotional marketing. In particular, we're going to look at Cats Effect 3 and ZIO 2. Now, for context, as of this writing ZIO 2 has released their first milestone; they have not released a final 2.0 version. This implies straight off the bat that we're comparing apples to oranges a bit, since Cats Effect 3 has been out and in production for months. However, there has been a post going around which cites various compar
| class Outer { | |
| class Inner | |
| type Type | |
| } | |
| trait Trait | |
| object Object extends Outer { | |
| val inner = new Inner | |
| } | |
| class OuterP[A] { | |
| class InnerP[B] |
| trait Enum { //DIY enum type | |
| import java.util.concurrent.atomic.AtomicReference //Concurrency paranoia | |
| type EnumVal <: Value //This is a type that needs to be found in the implementing class | |
| private val _values = new AtomicReference(Vector[EnumVal]()) //Stores our enum values | |
| //Adds an EnumVal to our storage, uses CCAS to make sure it's thread safe, returns the ordinal | |
| private final def addEnumVal(newVal: EnumVal): Int = { import _values.{get, compareAndSet => CAS} | |
| val oldVec = get |
Hi there!
The docker cheat sheet has moved to a Github project under https://github.com/wsargent/docker-cheat-sheet.
Please click on the link above to go to the cheat sheet.
| // summary : Just ONE ammonite script file to execute a load performance test using gatling ! | |
| // keywords : scala, gatling, ammonite, scala, load-test, performance | |
| // publish : gist | |
| // authors : David Crosson | |
| // license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2) | |
| // id : ea7a4259-9461-44a8-99fa-1ec6ec3c48ed | |
| // created-on : 2018-09-22T07:41:07Z | |
| // managed-by : https://github.com/dacr/code-examples-manager | |
| // execution : scala ammonite script (http://ammonite.io/) - run as follow 'amm scriptname.sc' |
| object StaticFile { | |
| // Various necessary imports. Notes: | |
| // | |
| // 1. fs2 is necessary. See https://github.com/functional-streams-for-scala/fs2 | |
| // 2. streamz is necessary. See https://github.com/krasserm/streamz | |
| // 3. Apache Tika is used to infer MIME types from file names, because it's more reliable and | |
| // fully-featured than using java.nio.file.Files.probeContentType(). | |
| // | |
| // If using SBT, you'll want these library dependencies and resolvers: |