domain specific languages and compilers

Question

I was looking over Martin Fowler's recent book contents - Domain Specific Languages and I noticed some ANTLR example - that got me thinking that writing compilers will become more and more popular since people needs in this matter will increase.

So, will the compiler theory still be as arid (being subjective here) as it was until now or are there any chances that we'll get more applied, programmer oriented materials ?

Answer 1

Even though DSLs may seem to create more opportunities for creating new compilers, I don't think they will make the challenges of writing a compiler any easier. You can either use compiler tools like yacc to generate code to handle your dsl syntax, or you can hand carve your own parser with an eye towards better internal efficiency than what the yacc generators spit out.

Either way, you have to have sufficient knowledge of how to define and manipulate a language grammar to make your DSL work and to avoid loopholes and can't-get-there-from-here problems.

Spiffy tools help to implement the solution, but they don't solve the problem for you. To quote my high school chemistry teacher: "Sure! Bring your calculators to class! Calculators only help you get the wrong answer faster!"

Answer 2

So, will the compiler theory still be as arid (being subjective here) as it was until now or are there any chances that we'll get more applied, programmer oriented materials ?

I'd say that compiler theory is actually pretty rich, but may not centered around C style languages. If you want to look at some powerful tools commonly used by academic language designers, I suggest that you check out functional programming languages (ML, Scheme, LISP, Haskell, OCaml, Scala, Clojure, etc.). Personally I prefer Haskell with Parsec, but there are many options. I think the common consensus is that the structure of these languages is more conducive to language design and implementation, at least in a theoretical sense.

Like Kristopher said above, programmers don't necessarily make the best language designers. I've seen some really cool DSL's and I've seen some pretty awful ones (my opinion, of course, YMMV). Knowledge of language concepts is a must for designing any language, DSL or otherwise (Type theory, category theory, various code analyses, machine optimization, etc). Not to mention, if you're designing a DSL, you have to have a fairly intimate knowledge of the domain you're targeting.

Tools off the shelf like yacc, ANTLR, flex, and cup can make building your compiler easier like buying wood from a lumberyard to build your house is easier than going off into the woods and cutting down trees. Both get you the material for the structure, but you still have to know how to build the house. We will definitely see more DSLs in the near future and these tools will help. Will the DSLs be worth using or even useable, however? The tools won't make a difference here, at least in my opinion. Language design employs a lot of real computer science and/or mathematics. Good language designers will have to at least be familiar with both, and good language implementers must be familiar with language design tools.