Scala, Java, Unix, MacOS tutorials (page 12)

Many websites seem to have the wrong lyrics for the Dave Matthews song, Grey Street, so to help correct that problem, here are the correct lyrics for the long version of Grey Street that Dave Matthews played with Tim Reynolds at “Live at Farm Aid 2021”:

Daniel Ingram was the first meditation teacher I ever heard who said that we should make meditation fun. He said something to the effect that when we sit down to meditate, we should try to sense vibrations as fast as possible — like playing a video game — and said, “Let’s bust some vibrations!”

Famous meditation teachers on staying mindful 24x7

As I think about trying to make meditation fun — and the use of mantras — I recall meditation teachers who have talked about the importance of staying mindful all day — 24x7 — to achieve enlightenment. For instance, here are just a few quotes:

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 20.3, “Scala best practice: Think "Expression-Oriented Programming".”

Problem

You’re used to writing statements in another programming language, and want to learn how to write expressions in Scala, and the benefits of the Expression-Oriented Programming (EOP) philosophy.

Because functional programming is like algebra, there are no null values or exceptions in FP code. But of course you can still have exceptions when you try to access servers that are down or files that are missing, so what can you do? This lesson demonstrates the techniques of functional error handling in Scala.

NOTE: This is a chapter from my book, Learn Scala 3 The Fast Way. Due to a mistake, this lesson was not included in the book.

When you write functions, things can go wrong. In other languages you might throw exceptions or return null values, but in Scala you don’t do those things. (Technically you can, but other people won’t be happy with your code.)

Instead what we do is work with error-handling data types. To demonstrate this I’ll create a function to convert a String to an Int.

As a little note here today, here’s an example of how to use a Scala Either inside a for-expression when using ZIO 2. In the code you’ll see that I convert each Either into a ZIO in each line of the for-expression.

This is an excerpt from the Scala Cookbook, 2nd Edition. This is Recipe 23.9, Simulating Dynamic Typing with Union Types.

Problem

When using Scala 3, you have a situation where it would be helpful if a value could represent one of several different types, without requiring those types to be part of a class hierarchy. Because the types aren’t part of a class hierarchy, you’re essentially declaring them in a dynamic way, even though Scala is a statically-typed language.

As a “note to self” about using ZIO 2, here are a few ZIO examples that show the ZIO.fail, ZIO.succeed, ZIO.attempt, orElseFail, and orDie methods and functions.

Before looking at the following code, it’s important to know that it uses the following Scala 3 enum:

Mostly because of Ram Dass books, and also more recently because of the book I Am That, I have been digging deeper than ever into the spiritual concept of “The Witness.” By that I mean both in terms of how we use the witness as a mindfulness and meditation technique, and also what that really means.

To that end I have started collecting Ram Dass quotes about the witness and the process of witnessing as a form of mindfulness, and the following are the Ram Dass quotes about the witness that I’ve found so far.

Everything changes once we identify with being the witness to the story