In this interview filmed at QCon SF 2008, Lennart Augustsson talks about writing DSLs in Haskell, presenting the advantages offered by the language. In that context, he talks about embedded DSLs, static and dynamic languages, syntax and semantics, monads and many other related topics.
Watch: Lennart Augustsson on DSLs Written in Haskell (25 min.)
Lennart starts by making a distinction between external DSLs - programming languages written in another language - and internal or embedded DSLs. He points out to the simple Haskell syntax which helps building a cleaner DSL. Also, he advertises Haskell’s closures allowing for lazy evaluation of code.
While some advocate Ruby and SmallTalk for writing DSLs due to their dynamic behavior, Lennart dismisses the claims that a statically typed language can’t be as useful as a dynamic one. He does not see any impediment in a static language when it comes to DSLs, but there rather benefits due to compile time type checking which eliminates some of the errors.
Lennart answers other questions about Haskell and it’s ability to write good DSLs. He also mentions F# and Scala as languages which are poised to become mainstream.