You may have recently come across The Super Tiny Compiler project. I read the code a handful of times back-to-back and decided to see if I could write a compiler myself, in Go. This project essentially just a port of the original one, which is written in JavaScript. With comments, it's around 1000 lines - without, only around 250.
$ git clone git@github.com:hazbo/the-super-tiny-compiler.git
$ cd the-super-tiny-compiler && go build -o tiny
$ ./tiny
Input: (add 2 (subtract 10 5))
Output: add(2, subtract(10, 5));
You can find the input towards the bottom of compiler.go.
$ go test
Feel free to issue a pull request if you feel there is something you could or would like to add to this project.