In my previous article, I showed how to embed a S7 Scheme interpreter in an iOS app. This time, I will show you how to embed a ClojureScript interpreter, or at least a dialect of it.

Clojure itself, runs on the JVM, and there’s not really a way to embed the JVM in an iOS app. Maybe once swift-java gets rolling.

There is GraalVM, which lets you compile java code to native code, but it doesn’t support compiling for iOS. Babashka, which is a native Clojure dialect interpreter uses GraalVM.

I am a fan of Lisp. I was first attracted to it because it was the original language of artificial intelligence because of its ability to manipulate symbols and its own code. I spent a whole year using Lisp in a series of courses on artificial intelligence in college. I became quite adept at using it and quite enjoyed using it as well.

My Obsession

Lately, I’ve become kind of obsessed with being able to use Lisp in my iOS apps. I want to put a Lisp interpreter in my app and program my business logic in Lisp. Every once in an awhile I get the urge to figure it out, try, and fail. This keeps happening.

This is part 6 of my blog series on the history of my app Numerology. See Part 5 here.

When we left off, Numerology was chugging along, slowly making less and less each month. First $300, then $200, sometimes as low as $100. Sometimes it would spurt back up to $300.

This continued until fairly recently. In 2024, I noticed a competitor that always showed up first in the App Store search results when you searched for ‘numerology’. I decided to look into them a little more. According to Sensor Tower, their app was making over $5,000/month on the Apple App Store. They had an Android app as well, and it was making $5,000/month as well.

This is part 5 of my blog series on the history of my app Numerology. See Part 4 here.

I was probably the first numerology app on the App Store. If you searched for numerology, my app would be first in the results. At some point this was no longer true. A competitor came out and my sales started to go down. Today, in 2025, there are possibly over a 100 numerology apps on the store.

This is part 4 of my blog series on the history of my app Numerology. See Part 3 here.

The First App Store Version

In 2008, Apple announced the App Store and I applied for an Apple Developer membership ($99/year), so I could sell apps on the App Store. Everyone else did the same and Apple was swamped. Despite applying as soon as possible, I didn’t get approved for about 6 months.

This is part 3 of my blog series on the history of my app Numerology. See Part 2 here.

The Birth of Cocoa

In 2001, Apple released the first version of Mac OS X 10.0, the first desktop version of their new OS based on NEXTStep. All the great APIs from NeXTStep (hence the NS prefixes to all the class names and such) together were called Cocoa.

Now I finally had my chance to use the wonderful platform I’d been wanting to use for almost a decade. My full-time job was still with Java and enterprise world and it was increasingly not fun. I spent my off-time learning Cocoa. My first app was not Numerology though. It was an app called PhoneWord that found all the words you could make from a phone number. For example, from the phone number 555-5299 you could get 555-JAZZ.

This is part 2 of my blog series on the history of my app Numerology. See Part 1 here.

The First Version

It was the very early 90’s. Steve Jobs was at NeXT. I had some model of Macintosh II running on a 680x0 processor. I also had a compiler for C with object-oriented extensions (basically a subset of C++), called THINK C, with a class library called TCL, or the Think Class Library. For more about THINK C, see this article.

Problem

Are you self-employed? Are you unemployed? Do you have to purchase your own health insurance?

Are you generally healthy, and rarely need a doctor? Are you into alternative health care, which health insurance never covers anyway?

Do you find “Affordable” health care, unaffordable like you see on healthcare.gov?

Do you find the whole process of finding the right plan and jumping through all the bureaucratic hoops frustrating?

I’m currently in this boat. The least expensive plan on the marketplace for me is over $700. That would make it the 2nd highest item on my monthly expense list. Right now, my monthly income is less than that. I simply can’t afford it.

Introduction

My app, Numerology, has been in the Apple app store for over 17 years. During that time, it and its variations (lite version, Mac version) have been downloaded over 188,000 times, and made almost $150,000 in profit.

Numerology Icon

It’s ran on just about every Apple iPhone, iPad, and Mac. Before the App Store, it even ran on classic macOS machines.

In my last job, I was on a platform team. One of the responsibilities of a platform team is to support all the other software development teams in an organization by writing libraries and tools that can be used by the other teams.

One of the libraries the platform team provided was a library that managed feature flags for the iOS app that our company produced. The primary function of the library was to get the current value of a given feature flag. If you’re not familiar with feature flags see Feature Flags 101: Use Cases, Benefits, and Best Practices. Basically, they are used to turn off and on features of an application at runtime.