https://en.wikipedia.org/wiki/TRAC_(programming_language)
https://en.wikipedia.org/wiki/Meta-circular_evaluator
4.1The Metacircular Evaluator
https://sarabander.github.io/sicp/html/4_002e1.xhtml
REYNOLDS Definitional Interpreters for Higher-Order Programming Languages REYNOLDS
https://web.archive.org/web/20170809042907/http://www.cs.uml.edu/~giam/91.531/Textbooks/definterp.pdf