Sohang Chopra sohang3112

MathJAX NOTES

Here we specifically mean MathJAX embedded inside Github Markdown only, not in any other context.

Inline expressions are written within $ $ , block expressions within $$ $$. Curly Brackets { } are required for grouping multiple symbols where otherwise only a single character/symbol is expected

eg. after _ (superscript under) and ^ (power/subscript over).

Notably MathJAX rendered by ChatGPT is a slightly different dialect - eg. it uses ( ) delimiters for inline expressions and [ ] for block expressions.

Generate new GPG key on laptop:

$ gpg --full-generate-key
$ gpg --list-secret-keys --keyid-format=long
$ gpg --armor --export GPG_KEY_ID    # get key id from prev list command - see details in above link

Copy output of last command (gpg armor export). Go to Github > Settings > SSH and GPG Keys > New GPG Key and paste it.

Problem

git push and git pull hanged (using SSH url).

Investigation

Enable tracing in git to check what's wrong:

$ GIT_TRACE=1 git push
trace: built-in: git push
trace: run_command: unset GIT_PREFIX; ssh git@github.com 'git-receive-pack '\''sohang3112/machine-learning-practice.git'\'''
trace: start_command: /usr/bin/ssh git@github.com 'git-receive-pack '\''username/repo.git'\'''

	from urllib.parse import urlparse, parse_qs

	safe_url = 'https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Foneconnect.hcltech.com%2Fnav_to.do%3Furi%3Dsysapproval_approver.do%253Fsys_id%3Dca1525483b4e32101de91624c3e45a99%2526sysparm_record_target%253dsysapproval_approver%2526sysparm_stack%3Dsysapproval_approver_list.do%253Fsysparm_query%3Dsys_created_on%253ejavascript%253ags.beginningOfToday()&data=05%7C02%7Csohang.chopra%40hcltech.com%7Cd4ac502f649d4ea5e89608de407bc9c7%7C189de737c93a4f5a8b686f4ca9941912%7C0%7C0%7C639019097585714357%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=Neefy3zdm1PRH0raNr9BS3IzBpNqpt7y4EB07D43tzY%3D&reserved=0'
	extracted_url = parse_qs(urlparse(safe_url).query)['url'][0]
	print('Extracted URL:', extracted_url)
	# Extracted URL: https://oneconnect.hcltech.com/nav_to.do?uri=sysapproval_approver.do%3Fsys_id=ca1525483b4e32101de91624c3e45a99%26sysparm_record_target%3dsysapproval_approver%

	# 'Squash Merge' video by anthonywritescode, this is script shown at timestamp 16:50 :
	# https://youtu.be/5_8FTivl8Vs?si=krcdLDevrAC_DLuo&t=1013
	# Uses https://github.com/newren/git-filter-repo (python script)

	# Explanation: `git cat-file commit COMMIT_ID` shows parent commit id
	# normal commits have 1 parent, merge commits have 2 parents
	# this script simply deletes 1 parent (keeping only parent id of main branch),
	# converting merge commit into normal (squash) commit

	# An impressive example of this script is shown,

	#! /usr/bin/env python3
	import os

	import fitz # PyMuPDF
	import nbformat

	# Source: https://www.reddit.com/r/learnpython/comments/1ji0qwz/comment/mjblesy/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
	def pdf_to_ipynb(pdf_path: os.PathLike, ipynb_path: os.PathLike) -> None:
	"""Convert PDF -> Jupyter Notebook .ipynb file."""
	doc = fitz.open(pdf_path)

	{-# LANGUAGE BangPatterns #-}

	import Data.List (foldl')

	-- \| Compresses a string by counting consecutive repeating characters.
	--
	-- Returns a list of tuples where each tuple consists of a character and the
	-- number of its consecutive occurrences in the string.
	--
	-- This function uses 'reverse', 'foldl'' and bang patterns for strict accumulation.

	# Example of forking ziglings repo from CodeBerg to Github
	UPSTREAM=https://codeberg.org/ziglings/exercises.git
	FORK=git@github.com:sohang3112/ziglings.git # mk empty Github repo & copy SSH url (as Github doesn't support push with HTTPS)

	git clone $UPSTREAM ziglings/ # (optional argument) used custom cloned folder name ziglings/
	cd ziglings/ # go to cloned repo
	git remote set-url origin $FORK
	git remote add upstream $UPSTREAM
	git push

	"""Using dict __missing__() to implement DefaultDict."""
	from typing import Any, Callable

	class DefaultDict(dict):
	"""Implementing typing.DefaultDict.

	A dict that returns a default value (instead of raising KeyError) when a key is missing.

	>>> d = DefaultDict(list, {'a': 1, 'b': 2})
	>>> d['a']