Add a basic README

Author: mkantor

README.md

@@ -0,0 +1,36 @@
+# Please
+
+An exploratory programming language.
+
+## Quick start
+
+```sh
+git clone [email protected]:mkantor/please-prototype.git
+cd please-prototype
+npm install
+npm run build
+echo '{@runtime context => :context.program.start_time}' | ./please --output-format=json
+```
+
+## What this repository is
+
+**This implementation of Please is a proof of concept**. There are plenty of bugs and missing
+pieces, and language syntax/semantics may change backwards-incompatibly on the way to an official
+release. This implementation is not particularly focused on performance, robustness, or developer
+experience—it's merely a place to experiment with ideas for the language. TypeScript was chosen
+because it's pretty good for rapid prototyping, but it's likely that another language will be used
+in a non-prototype implementation.
+
+## Current state
+
+Enough pieces exist to write basic runnable programs. There is a type system, but it's not wired up
+in many places yet so mistakes often go unnoticed at compile time. The standard library is anemic,
+and it's not uncommon to encounter bugs in the compiler/runtime.
+
+The current implementation of the runtime is an interpreter, but the plan is to eventually add one
+or more backends to allow building native executables.
+
+## What's next?
+
+I'm focused on squashing compiler bugs and establishing solid foundations to build atop. Along the
+way I've been slowly fleshing out the type system and standard library.