Read this paper: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.34.3972 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.34.3... In Prolog (as

Read this paper: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.34.3972 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.34.3... In Prolog (as with Haskell, OCaml, and others), you can define new operators with user-definable meaning and precendence. ->, !, and some other operators used in Erlang were left undefined in Prolog specifically for making DSLs. (That's also why Erlang code looks approximately like Prolog code with a bunch of extra operators added - it was a Prolog DSL.) Prolog is a pretty good language for quickly protyping interpreters.