snix/nix/buildLisp/README.md

buildLisp.nix

This is a build system for Common Lisp, written in Nix.

It aims to offer an alternative to ASDF for users who live in a Nix-based ecosystem. This offers several advantages over ASDF:

• Simpler (logic-less) package definitions
• Easy linking of native dependencies (from Nix)
• Composability with Nix tooling for other languages
• Effective, per-system caching strategies
• Easy overriding of dependencies and whatnot
• ... and more!

The project is still in its early stages and some important restrictions should be highlighted:

• Only SBCL is supported (though the plan is to add support for at least ABCL and Clozure CL, and maybe make it extensible)
• Parallel compilation is not possible: Since buildLisp doesn't encode dependencies between components (i. e. source files) like ASDF, it must compile source files in sequence to avoid errors due to undefined symbols.

Usage

buildLisp exposes four different functions:

• buildLisp.library: Builds a collection of Lisp files into a library.

  parameter	type	use	required?
  name	string	Name of the library	yes
  srcs	list<path>	List of paths to source files	yes
  deps	list<drv>	List of dependencies	no
  native	list<drv>	List of native dependencies	no
  test	see "Tests"	Specification for test suite	no

  The output of invoking this is a directory containing a FASL file that is the concatenated result of all compiled sources.

• buildLisp.program: Builds an executable program out of Lisp files.

  parameter	type	use	required?
  name	string	Name of the program	yes
  srcs	list<path>	List of paths to source files	yes
  deps	list<drv>	List of dependencies	no
  native	list<drv>	List of native dependencies	no
  main	string	Entrypoint function	no
  test	see "Tests"	Specification for test suite	no

  The main parameter should be the name of a function and defaults to ${name}:main (i.e. the exported main function of the package named after the program).

  The output of invoking this is a directory containing a bin/${name}.

• buildLisp.bundled: Creates a virtual dependency on a built-in library.

  Certain libraries ship with Lisp implementations, for example UIOP/ASDF are commonly included but many implementations also ship internals (such as SBCLs various sb-* libraries).

  This function takes a single string argument that is the name of a built-in library and returns a "package" that simply requires this library.

• buildLisp.sbclWith: Creates an SBCL pre-loaded with various dependencies.

  This function takes a single argument which is a list of Lisp libraries programs or programs. It creates an SBCL that is pre-loaded with all of that Lisp code and can be used as the host for e.g. Sly or SLIME.

Tests

Both buildLisp.library and buildLisp.program take an optional argument tests, which has the following supported fields:

parameter	type	use	required?
name	string	Name of the test suite	no
expression	string	Lisp expression to run tests	yes
srcs	list<path>	List of paths to source files	no
native	list<drv>	List of native dependencies	no

the expression parameter should be a Lisp expression and will be evaluated after loading all sources and dependencies (including library/program dependencies). It must return a non-NIL value if the test suite has passed.

Example

Using buildLisp could look like this:

{ buildLisp, lispPkgs }:

let libExample = buildLisp.library {
    name = "lib-example";
    srcs = [ ./lib.lisp ];

    deps = with lispPkgs; [
      (buildLisp.bundled "sb-posix")
      iterate
      cl-ppcre
    ];
};
in buildLisp.program {
    name = "example";
    deps = [ libExample ];
    srcs = [ ./main.lisp ];
    tests = {
      deps = [ lispPkgs.fiveam ];
      srcs = [ ./tests.lisp ];
      expression = "(fiveam:run!)";
    };
}