What?

What?

Languages that do this

Why?

- provides a large codebase for working on (dogfooding)

- encourages language improvements (perf and features)
   

- provides a big example project

Why not?

- takes a long time

- initially will be slower (perf)

- language bugs or missing features hold back development

- May require features that you didn't intend to add to a language

How

Start with a regular compiler

it can be in any language, but similarity to both the compiled output and the target language is helpful

Create a stable version  

- Write a lot of tests

- Have a benchmark

Rewrite your compiler in the target language

Use the test suite and benchmarks to guide you and fix errors

Release a version with the new compiler 

From then on, your compiler must be written in code on the n-1th version