Cihat Altuntaş caltuntas

Note: this was originally several Reddit posts, chained and linked. But now that Reddit is dying I've finally moved them out. Sorry about the mess.

URL: https://www.reddit.com/r/ProgrammingLanguages/comments/up206c/stack_machines_for_compilers/i8ikupw/ Summary: stack-based vs register-based in general.

There are a wide variety of machines that can be described as "stack-based" or "register-based", but not all of them are practical. And there are a lot of other decisions that affect that practicality (do variables have names or only address/indexes? fixed-width or variable-width instructions? are you interpreting the bytecode (and if so, are you using machine stack frames?) or turning it into machine code? how many registers are there, and how many are special? how do you represent multiple types of variable? how many scopes are there(various kinds of global, local, member, ...)? how much effort/complexity can you afford to put into your machine? etc.)

a pure stack VM can only access the top elemen

Introduction
Standards
Common combinations
Conversion
Verification/Inspection
Tips for recognising

Introduction

It happens that there are many standards for storing cryptography materials (key, certificate, ...) and it isn't always obvious to know which standard is used by just looking at file name extension or file content. There are bunch of questions on stackoverflow asking about how to convert from PEM to PKCS#8 or PKCS#12, while many tried to answer the questions, those answers may not help because the correct answer depends on the content inside the PEM file. That is, a PEM file can contain many different things, such as an X509 certificate, a PKCS#1 or PKCS#8 private key. The worst-case scenario is that someone just store a non-PEM content in "something.pem" file.

A non-exhaustive list of WebGL and WebGPU frameworks and libraries. It is mostly for learning purposes as some of the libraries listed are wip/outdated/not maintained anymore.

Engines and libraries

three.js: JavaScript 3D library
stack.gl: an open software ecosystem for WebGL, built on top of browserify and npm.
PixiJS: Super fast HTML 5 2D rendering engine that uses webGL with canvas fallback
Pex: Pex is a javascript 3d library / engine allowing for seamless development between Plask and WebGL in the browser.
Babylon.js: a complete JavaScript framework for building 3D games with HTML 5 and WebGL
Filament: Filament is a real-time physically based rendering engine for Android, iOS, Windows, Linux, macOS and WASM/WebGL
ClayGL: A WebGL graphic library

Zathura on Mac

I want to open PDF files with Zathura on Mac. Problem is - Zathura does not have a proper App Bundle. So you cannot go in Finder to a pdf file, navigate to ‘Get Info’ and set pdf files to be opened with Zathura.

Luckily, you can create a custom App Bundle that wraps up a script that does that

But that is not as straightforward as you think it is, you can’t just execute a shell script. What if the file already opened with one of the instances of zathura process? Since Zathura is not a native OSX app, it will create a new process instance every time you open it.

The following script opens a file in Zathura, and if it was already opened, it would only activate the right window.

How to use it

Common zsh Keyboard Shortcuts on macOS

Navigation

CTRL + A : Move the cursor to the beginning of the line
CTRL + E : Move the cursor to the end of the line
OPTION + Left Arrow : Move the cursor one word backward
OPTION + Right arrow : Move the cursor one word forward
Left Arrow : Move the cursor one character backward
Right Arrow : Move the cursor one character forward

Testing Multicast Traffic on Linux

Prerequisites

By default Linux ignores Broadcast and Multicast ICMP messages. That's why you need to enable it first:

sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=0

Join and Test Multicast Traffic

To join any mutlicast address (e.g. 224.10.10.10/24) just add it to your active interface (e.g. eth0) and append the keyword autojoin at the end:

	# make a query at this point in time
	$ promtool query instant http://localhost:9090 '{job=~".+"}'
	up{instance="localhost:9090", job="prometheus"} => 1 @[1690724237.225]
	go_memstats_alloc_bytes{instance="localhost:9090", job="prometheus"} => 29046776 @[1690724237.225]
	...

	# query a metric for the time range between two Unix timestamp
	$ promtool query range --start 1690724700 --end 1690725307 --step 1m http://localhost:9090 \
	'go_memstats_alloc_bytes{job="prometheus"}'
	23215032 @[1690724700]

	" Pick a different highlighting group by adding this in your vimrc:
	"
	" highlight link fuzzyMatch <group>
	"
	" The "default" only makes the link if it's not already set.
	"
	highlight default link fuzzyMatch Search

	" The components of the command definition:
	"

	#######################################################################################################
	#
	# How to install the mssql-cli on Ubuntu 22.04 running python 3.10
	#
	# This is pretty hacky so please only do this on dev/test servers
	#
	# The first few steps here will also get the mssql-cli working on Ubuntu 20.04 (running python 3.8)
	#
	#######################################################################################################

	#!/usr/bin/awk -f

	# This program is a copy of guff, a plot device. https://github.com/silentbicycle/guff
	# My copy here is written in awk instead of C, has no compelling benefit.
	# Public domain. @thingskatedid

	# Run as awk -v x=xyz ... or env variables for stuff?
	# Assumptions: the data is evenly spaced along the x-axis

	# TODO: moving average