eo VS jcabi-github

They do have a paper in the repo: https://github.com/cqfn/eo/tree/master/paper

According to it, "𝜑-calculus" is something they made up for the eolang and not a standard term.

Here is my take on that calculus based on reading through section 3 in the paper. Note the paper is pretty weird and likes to make its own notation, so it is possible I got some things wrong:

It is starts with a pretty standard immutable language: "object" is a set of (name, value) pairs; "value" is either object or "data" (like a string, bool etc...); everything is immutable but you can make a copy an object with some attributes changed. There are no concept of "types" -- instead, you define objects with some fields set to NULL (spelled ∅ in the paper). There are also a bunch of term defined, like "abstraction", "application", etc.. -- but they all mean "make a copy of an object with some fields changed".

The "twist" is that the language has no functions per se, instead it defines AST-like structure: there is a syntactic sugar that handles things that look like function applications. So when you see:

     stdout "Hello world"

The jcabi-github dependency looked nice in the beginning but it was having issues with the event feed management, the endpoints were not properly setup in the code, but it was only a minor issue, I was able to overcome it by using two different operations to fetch the required data.

Here's an example of what I mean: https://github.com/jcabi/jcabi-github/ (it's a Java client for Github's API).