I will also note, that while it's possible to build a parser generator for external DSLs, for many use cases concrete syntaxes with existing parsers work fine. Back in 2000 I created a set of DSLs for generating web applications and I used the concrete, serializable syntax of XML as I got the capacity to describe types fairly clearly and I didn't need to generate a parser (or more importantly, an IDE plugin with auto complete and type validation). I figured I could always write a lightweight interface to display the info from the concrete DSLs to save business users from the angle brakcets. Json would allow you to do the same these days.