Re: [Sbcl-help] How to use a macro defined in another file

[Nikodemus S. <nik...@ra...>]

On 30 July 2010 07:43, Cecil Westerhof <Ce...@de...> wrote:

> In another file I have:
>    (defmacro define-constant (name value &optional doc)
>      `(defconstant ,name (if (boundp ',name) (symbol-value ',name) ,value)
>         ,@(when doc (list doc))))

> The definition is included with:
>    (load (merge-pathnames "clisp/script-utils" (user-homedir-pathname)))
>
> But when doing:
>    (define-constant +db+ (merge-pathnames "recepten.db" (user-homedir-pathname)))
> there is an error.
> The folowing does work:
>    (defvar +db+ (merge-pathnames "recepten.db" (user-homedir-pathname)))
>
> Variables and functions defined in ~/clisp/script-utils do not have a
> problem. (As far as I know.)
>
> When giving 'C-x C-e' after the definition of define-constant I can
> use define-constant. What am I doing wrong?
>
> I also tried it in sbcl standalone and there I got:
>    * (load (merge-pathnames "clisp/script-utils" (user-homedir-pathname)))
>
>    T
>    * (define-constant +db+ (merge-pathnames "recepten.db" (user-homedir-pathname)))
>
>    ; in: DEFINE-CONSTANT +DB+
>    ;     (DEFINE-CONSTANT +DB+ (MERGE-PATHNAMES "recepten.db" (USER-HOMEDIR-PATHNAME)))
>    ;
>    ; caught WARNING:
>    ;   undefined variable: +DB+
>    ;
>    ; caught STYLE-WARNING:
>    ;   undefined function: DEFINE-CONSTANT

This almost certainly an indication that DEFINE-CONSTANT is not
defined in the package you are in.

Try (apropos "DEFINE-CONSTANT") after loading the file with
DEFINE-CONSTANT too see what package it is in.

I'm guessing script-utils has something like

 (defpackage :script-utils
    (:use :cl)
    (:export #:define-constant))

 (in-package :script-utils)

at top, and presumably value of *PACKAGE* in the REPL is not
:SCRIPT-UTILS. You need to either qualify the name

  (script-utils:define-constant ...)

or get the definitions into your current package via IMPORT or
USE-PACKAGE (or :USE clause in the relevant DEFPACKAGE.)

If you're just working in CL-USER, simply do

  (use-package :script-utils) ; or whatever the correct package name is

in the REPL after loading the script-utils file.

However, if DEFINE-CONSTANT is not exported, you need to IMPORT it instead

  (import 'script-utils::define-constant)

...or better yet, add it to the :EXPORT clause in the DEFPACKAGE in that file.

Practical Common Lisp has a good chapter on packages.

Cheers,

 -- Nikodemus