This Month with Nim: October 2021

02 November 2021 The Nim Community

Turing Complete

Author: Stuffe

In this challenging puzzle game, you build a computer from scratch and program it. It is a journey through the layers of abstractions of the computer. The game begins when you are abducted by aliens who are testing your intelligence, and from here a lighthearted sci-fi plot evolves. It is available on Steam.

This game was made in Godot and Nim with godot-nim.

changer

Author: Iffy

I love projects that keep an accurate changelog. But most people (me included) don’t like maintaining a changelog or fixing conflicts in the changelog. With changer you can add a conflict-free, easy-to-maintain changelog to your project!

Initial setup:

nimble install changer
mkdir myproject && cd myproject
changer init

Any time you want to add a new changelog entry run changer add and follow the two prompts:

$ changer add
Change type:
  [F]ix
  [N]ew feature
  [B]reaking change
  [O]ther (default)

Describe change (this will show up in the changelog): 
This project has a changelog now!
changes/new-This-project-has-20211005-132645.md

When you’re ready to release a new version run changer bump to combine all pending changes into the CHANGELOG.md file.

$ cat CHANGELOG.md 
# v0.1.0 - 2021-10-05

- **NEW:** This project has a changelog now!
- **FIX:** Fixed a broken thing

Changer can also convert issue numbers into links (or do other simple substitutions), automatically change the version in your .nimble file or even a package.json file. Happy coding!

OOlib

Authors: Neo

OOlib is a nimble package for object oriented programming in Nim. Example:

import strformat
import oolib

# add `pub` prefix to export class
class pub Person:
  var
    name*: string
    age* = 0

  # auto insert `self` as first argument
  proc `$`*: string = fmt"<Person> name: {self.name}"

  proc happyBirthday* =
    inc self.age

# auto define constructor
let p1 = newPerson("Tony")
let p2 = newPerson("Steve", 100)

It has the following features:

Member variables with default values
Class data constants
Definition of proc, method, func, etc… (the only exception being macro)
Auto inserting self as first argument
Auto definition of constructor (high performance!)
Assistance with constructor definition
pub modifier instead of *
Inheritance with of modifier
Creating distinct type with distinct modifier
{.final.} by default
{.open.} to allow inheritance
super keyword for method
Alias class

More features are planned:

Pick like TypeScript’s Pick
let member variables
struct
protocol like interface

LibVF.IO

Author: Arthur Rasmusson

LibVF.IO is commodity GPU multiplexing driven by YAML & VFIO. We wrote an article about it here.

LibVF.IO is made in Nim. :)

Metaprogramming in Nim: Introduction

Author: Kiloneie

In this video I show and teach Nim’s metaprogramming features and capabilities. Each of its features are explained and demonstrated in a beginner-friendly manner.

Nimscripter 1.0.0 - The Rewrittening

Author: Jason Beetham

Over the past few months I have slowly been chipping at a Nimscripter rewrite and got it to a usable state in October! No longer does it rely on silly string serialization or other annoying things, you can now easily expose code to a VM and call it or expose VM code to the compiled code and call it. The following is a simple example:

import nimscripter
addCallable(someNSModule):
  proc doThing(a: int): int

var someNum = 10
proc doOtherThing: bool = true
exportTo(someNsModule,
  someNum,
  doOtherThing)
const
  script = """
proc doThing*(a: int): int = 
  if doOtherThing():
    someNum * a
  else: 0
"""
  addins = implNimScriptModule(someNsModule)
let intr = loadScript(NimScriptFile(script), addins)
assert intr.invoke(doThing, 2, returnType = int) == 2 * someNum
someNum = 30
assert intr.invoke(doThing, 4, returnType = int) == 4 * someNum

What’s that I hear, “Oh it’d be cool if it worked with emscripten”?! Well it does!

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