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LIL: abstract interfaces and supporting concrete data-structures in Common Lisp
Common Lisp Racket
branch: master


LIL: abstract interfaces and concrete data structures in Common Lisp


  • LIL nicely combines ad-hoc polymorphism (CLOS-powered object oriented programming) and parametric polymorphism (as in ML functors, C++ templates, etc.). To our knowledge, only scalaz matches the expressiveness of LIL.

  • LIL sports both pure (persistent, immutable) and stateful (ephemeral, mutable) variants of data structures in Interface-Passing Style. This variants are in the respective packages PURE and STATEFUL; a common core is shared in package INTERFACE, covering read-only operations; automatic transforms allow bridging from stateful to pure and back.

  • LIL supports data structures in traditional Object-Oriented Style, in both stateful (the usual Object-Oriented kind) and pure variants, in the respective packages POSH and CLASSY. There too, automatic transforms to go from Interface-Passing Style to traditional Object-Oriented Style and back.

Building it

LIL needs to be built using ASDF 3 or later:

LIL was recently converted to use the asdf-package-system, whereby instead of dependencies being listed in a central .asd file, each source file has a defpackage form from which the dependencies are deduced. While we think it's a good way to write Lisp code, you don't have to use it in your own code to use LIL. We're hoping that asdf-package-system will soon be part of ASDF itself, but until an updated version of ASDF is universally available, you can find it here:

LIL also depends on fare-utils, fare-memoization, closer-mop, alexandria:

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