Some Lisp programs such as Emacs, but also the Linux kernel (when fully modularised) are mostly dynamic; i.e., apart from a small static core, the significant functionality is dynamically loaded. In this paper, we explore fully dynamic applications in Haskell where the static core is minimal and code is hot swappable. We demonstrate the feasibility of this architecture by two applications: Yi, an extensible editor, and Lambdabot, a pluginbased IRC robot. Benefits of the approach include hot swappable code and sophisticated application configuration and extension via embedded DSLs. We illustrate both benefits in detail at the example of a novel embedded DSL for editor interfaces. Categories and Subject Descriptors D.3.3 [Programming Languages]: Language Constructs and Features General Terms Design, Languages Keywords Dynamic applications, Hot swapping, Dynamic update, Extension languages, Functional programming
Don Stewart, Manuel M. T. Chakravarty