Add docs to lib.rs

reid/src/lib.rs

@@ -1,3 +1,35 @@
+//! Reid is a toy-language compiler I'm working on to learn LLVM (and compiler
+//! development).
+//!
+//! Reid only uses [llvm-sys](https://gitlab.com/taricorp/llvm-sys.rs), which
+//! provide very minimal bindings from the LLVM C-API to Rust. `reid_llvm`-crate
+//! contains the relevant abstraction to produce a more Rust'y API from that.
+//!
+//! Much of the syntax in Reid is directly inspired by rust, but mostly it is
+//! driven by simplicity.
+//!
+//! Currently missing relevant features (TODOs) are:
+//! - Arrays
+//! - Structs (and custom types as such)
+//! - Extern functions
+//! - Strings
+//! - Loops
+//!
+//! An example program of Reid, that calculates the 5th fibonacci number (and
+//! uses Rust for highlighting) is:
+//! ```rust
+//! fn main() -> u16 {
+//!     return fibonacci(5);
+//! }
+//!
+//! fn fibonacci(n: u16) -> u16 {
+//!     if n <= 2 {
+//!         return 1;
+//!     }
+//!     return fibonacci(n-1) + fibonacci(n-2);
+//! }
+//! ```
+
 use mir::typecheck::TypeCheck;
 use reid_lib::Context;
 
@@ -11,13 +43,6 @@ mod pad_adapter;
 mod token_stream;
 mod util;
 
-// TODO (Missing Relevant Features):
-// - Arrays
-// - Structs (and custom types as such)
-// - Extern functions
-// - Strings
-// - Loops
-
 #[derive(thiserror::Error, Debug)]
 pub enum ReidError {
     #[error(transparent)]