Mac上使用Clozure CL调用LTK库时BUTTON类未找到问题求助

Hey there! Let's break down why you're seeing that error when running your hello-1 function, even though LTK's built-in tests like (ltk::ltk-eyes) work perfectly. The root issue almost always comes down to how you're referencing LTK's classes and functions in your code.

Why the built-in tests work, but your code doesn't #

LTK's pre-written test functions (like ltktest) live inside the LTK package, and they already use fully qualified names for all LTK-specific symbols (like ltk:button). When you run them directly, the Lisp interpreter knows exactly where to find those classes. Your custom hello-1 function, though, is probably running in the default CL-USER package, which doesn't automatically have access to LTK's symbols.

Solution 1: Import LTK's symbols into your current package #

Add a use-package call at the top of your code (or in the REPL) to pull all LTK's public symbols into your working package. Here's a corrected version of the hello-1 example from the LTK docs:

;; First load LTK if you haven't already
(ql:quickload "ltk")

;; Import LTK's symbols into the current package
(use-package :ltk)

(defun hello-1 ()
  (with-ltk ()
    (let ((b (make-instance 'button
                            :text "Hello World"
                            :command (lambda () (format t "Hello World~&")))))
      (pack b))))

Now when you call (hello-1), the interpreter will recognize button, with-ltk, and pack as LTK symbols.

Solution 2: Use fully qualified names (no use-package needed) #

If you prefer not to pollute your current package with LTK's symbols, you can prefix every LTK-specific symbol with the package name ltk::

(ql:quickload "ltk")

(defun hello-1 ()
  (ltk:with-ltk ()
    (let ((b (make-instance 'ltk:button
                            :text "Hello World"
                            :command (lambda () (format t "Hello World~&")))))
      (ltk:pack b))))

This explicitly tells the interpreter to look for button and other symbols in the LTK package.

Solution 3: Define a custom package that uses LTK #

If you're writing a larger project, it's best practice to create your own package that explicitly includes LTK as a dependency:

(defpackage :my-ltk-app
  (:use :cl :ltk)) ; Use both Common Lisp and LTK symbols
(in-package :my-ltk-app)

(defun hello-1 ()
  (with-ltk ()
    (let ((b (make-instance 'button :text "Hi there!" :command (lambda () (print "Hi!")))))
      (pack b))))

This way, all code in my-ltk-app will automatically have access to LTK's symbols without needing extra use-package calls.

Quick check in the REPL #

If you're testing in the REPL, you can verify if LTK's symbols are available by running:

(find-symbol "BUTTON" :ltk)

If this returns (LTK:BUTTON :EXTERNAL), the class exists—you just need to make sure your code can see it via one of the methods above.

内容的提问来源于stack exchange，提问作者marco_rexo