Call function in another lisp file

Question

I have to write a game in Lisp. In order to make it clear, I wanted to split the code in different .lisp files.

How can I call a function out of a function in the ot

Answer 1

Just so you know, there are a variety of different Lisp systems. I'll post the answer for Common Lisp.

The naive way is to use (load "filename.lisp"), but that doesn't really work very well after a while. Therefore...

Common Lisp has a library called "ASDF", which handles packaging and file management. There's a bit of setup to ASDF.

1. Create directory where ASDF looks for files.
2. Add this information to my Lisp system's init file.

I use this in my .sbclrc file (assuming that I created a .asdf file in ~) :

(pushnew "~/.asdf/" asdf:*central-registry* :test #'equal)

I usually use a previously built ASDF file and then modify it.

Here's a sample ASDF file's contents:

(asdf:defsystem #:cl-linq
  :depends-on ( #:alexandria #:anaphora)
  :components ((:file "cl-linq"))
  :name "cl-linq"
  :version "0.1"
  :maintainer "Paul Nathan"
  :author "Paul Nathan"
  :licence "LLGPL"
  :description "CL LINQ style interface with strains of SQL"
  :long-description
  "DSL for managing and querying datasets in a SQL/LINQ style
syntax. cl-linq provides a simple and usable set of primitives to
make data examination straightforward. ")

I put this code in a file cl-linq.asd next to my source code (cl-linq.lisp from the component "cl-linq" in the defsystem) and then symlink the cl-linq.asd file to my ~/.asdf/ directory.

Within my cl-linq.lisp file I include this:

(defpackage :cl-linq
  (:use
   :common-lisp
   :anaphora)
  (:export
   #:query
   #:cl-linq-select))
(in-package :cl-linq)

So for your case, I would have 2 components; each with their own defpackage form, exporting the functions out that the other package needed.

For the examples, I've taken the code from CL-LINQ, a project of mine. You are quite free to use it as a template.