Thorsten Ball, author of Writing an interpreter in Go as well as its sequel Writing a Compiler in Go. Adam Gordon Bell spoke with Ball about building an interpreter. Topics covered include the differences between an interpreter and a compiler, what languages are most commonly used for writing interpreters, the advantages and disadvantages of go, tokenizing input, building a parser without the aid of a parser generator, abstract syntax trees, the monkey programming language, evaluating abstract syntax trees and a discussion of the size of various real-world language implementations.