Mastering Python Design Patterns - Second Edition

Interpreter pattern

Usually, what we want to create is a domain-specific language (DSL). A DSL is a computer language of limited expressiveness targeting a particular domain. DSLs are used for different things, such as combat simulation, billing, visualization, configuration, communication protocols, and so on. DSLs are divided into internal DSLs and external DSLs, j.mp/wikidsl, and j.mp/fowlerdsl.

Internal DSLs are built on top of a host programming language. An example of an internal DSL is a language that solves linear equations using Python. The advantages of using an internal DSL are that we don't have to worry about creating, compiling, and parsing grammar because these are already taken care of by the host language. The disadvantage ...