My original intention in reading this book was to see if it’s straightforward to build a shcal(1) UNIX utility, which would be the Solar Hijri version of cal(1) (link to specs) POSIX-standardized utility. It is 10 days past Nowruz so I can still make it seasonal.

However I found this book itself is very entertaining. It is not aimed at just programmers, it can be used by people of all trades. It has a nice ‘aesthetic’. Like a 13 year old American girl addicted to TikTok would give it a ‘Scholar Core’ label. It is still a reference book, but their reference sections is clean and thorough.

I highly recommend giving it a read. It explains calendars from like a billion years ago. These are truly men of letters writing these, so let’s call it ‘Letters Core’!