Most of my interest stems from this excellent project in Racket that's shaping up to be quite something:
https://github.com/lexi-lambda/hackett
It uses the "type systems as macros" paper's approach to create a Haskell-like language in Racket.
(btw, I think you meant e.g., not i.e.)
Yes! You can override the reader so that it parses anything, and there are modules for writing grammers[1][2]. Still, it is usually much easier to just use the built in s-expression parser, and if you're writing a lot of lisp, you probably don't mind s-expressions anyways :)
Hackett has interested me too, I hope that progress can continue to be made, it would be a nice alternative to Typed Racket (which is great, but very complex).
I'm working with the author of the "Type Systems as Macros" paper right now, we're working on implementing a linear language (along the lines of Rust) using Racket's macro facilities and the turnstile[3] package. Being able to embed arbitrary type systems in Racket really shows the insane power of the macro system.
[1] http://docs.racket-lang.org/parser-tools/LALR_1__Parsers.htm...
Great comment. And if a domain-specific-language (DSL) of really custom syntax is needed, an alternative is to use Racket (a Lisp-family language), which allows for creating DSLs of all kind. Racket is already used for designing your own programming language and trying it, so I'm surprised that the author did not mention suggest Racket as a test-bed for the new language.
> This article is sort of fundamentally wrong that it's difficult to write small, purpose built languages. It's not, and even outside the functional and homoiconic meta-syntactic world we have seen code generators deployed regularly.
Correct. For example, most of the common systems used today do use a 'code generator' internally: Every software that uses an ORM library (i.e. Hibernate), is already using a sort of domain-specific-language (i.e. HQL) that, via a code generator, translates to another language (i.e. SQL). So most major platforms (Java, .NET, etc) already have one or many popular libraries that do implement some sort of (limited) DSL and code generator.
I think the aim of the article was to create a new compiler from the ground-up. I think the correct choice for syntax is something that can't be boiled down to three pieces of advice or one article. It is a topic that would require very deep discussion.