Improve readme

README.md

@@ -1,10 +1,42 @@
-# Ludus, in Clojure
-## Or, CLudus
+![Ludus logo](logo.png)
+## Ludus: A friendly, dynamic, functional language
 
-A reference implementation of an interpreter for the Ludus programming language. It's written in Clojure. It's a tree-walk interpreter, very slow. (We are following the Nystrom path from _Crafting Interpreters_.)
+A reference implementation of an interpreter for the Ludus programming language, using Clojure as a host language.
+
+Ludus is part of the [_Thinking with Computers_ project](https://thinking-with-computers.github.io), run by Scott Richmond at the University of Toronto. Ludus is our research language, which aspires to be a free translation of Logo for the 2020s.
+
+### Status
+Pre-alpha, still under active development. See [the ludus-spec repo for progress notes and additional documentation](https://github.com/thinking-with-computers/ludus-spec/blob/main/todo.md).
 
 ### Use
 * Clone this repo.
+	- `git clone https://github.com/thinking-with-computers/cludus`
 * Have Clojure and Leiningen installed.
-* `lein run {script}`, it runs your script in Ludus!
-* Ludus is very much a work in progress; see [the ludus-spec repo for progress notes](https://github.com/thinking-with-computers/ludus-spec/blob/main/todo.md).
+	- On a Mac: `brew install clojure leiningen`
+* `lein run {script}`, it runs your script.
+* Alternately, download a binary on the [releases page](https://github.com/thinking-with-computers/cludus/releases).
+
+### `Hello, world!`
+Ludus is a scripting language. At current it does not have a REPL (our aim is to get interactive coding absolutely correct).
+
+Either
+```
+"Hello, world!"
+```
+`=> "Hello, world!"`
+
+Ludus scripts (and blocks) simply return their last expression; this script returns the bare string (to `stdout`) and exits.
+
+Or:
+```
+print ("Hello, world!")
+```
+```
+=> Hello, world! 
+=> :ok
+```
+
+Or, you can use a the `print` function, which sends a string to `stdout`. Because `print` returns the keyword `:ok` when it completes, that is the result of the last expression in the script--and so Ludus also prints this.
+
+### More on Ludus
+Most of the (very active, somewhat messy) thinking about Ludus is housed in the [ludus-spec repository](https://github.com/thinking-with-computers/ludus-spec).