A compiler can be characterized by three languages:
The T- diagram shows a compiler SCIT for Source S, Target T, implemented in I.
Follow some steps to produce a new language L for machine A:
1. Create a compiler SCAA for subset, S of the desired language, L using language "A" and that compiler runs on machine A.
2. Create a compiler LCSA for language L written in a subset of L.
3. Compile LCSA using the compiler SCAA to obtain LCAA. LCAA is a compiler for language L, which runs on machine A and produces code for machine A.
The process described by the T-diagrams is called bootstrapping.