eo VS golo-lang

Looking at the commit history of eo, I'm not certain that PR size, or testing methodology for that matter, should be the #1 concern of Yegor's team.

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"

More info: https://github.com/eclipse/golo-lang/issues/581