Tutorial: Creating, Loading, and Opening an AutoLISP File (AutoLISP)

AutoLISP is an interpretive language, so it can be stored in a text file, loaded, and then executed directly within AutoCAD.

AutoLISP files typically have an .lsp file extension, but they can also have the .mnl file extension. Both LSP and MNL files can be edited with a text editor, such as Notepad on Windows and TextEdit on Mac OS.

Note: AutoLISP is not available in AutoCAD LT for Mac OS.

MNL files are associated with user interface customization and they are automatically loaded into AutoCAD when a customization (CUI/CUIx) file of the same name is loaded. For example, the acad.mnl is automatically loaded into AutoCAD when the acad.cuix file is loaded.

Note: AutoCAD LT doesn't support the automatic loading of MNL files, but the files can be loaded using the AutoLISP LOAD function from another LISP file.

Creating an AutoLISP (LSP) File

Here is how to create a file with the .lsp extension and add the C:HELLO function defined in the Creating a New Command and Working with System Variables tutorial.

Windows
  1. Click the Windows Start button, and then click Windows Accessories Notepad.
  2. In Notepad, click File menu Save As.
  3. In the Save As dialog box, browse to the Documents folder. Right-click in an empty area, not over a file or folder, and click New Folder. Enter the name LSP Files for the name of the new folder and press Enter. Double-click the new folder LSP Files to make sure it is the current folder.
  4. In the File Name text box, enter Create-LSP-Tutorial.lsp.
  5. Click the Save As Type drop-down list and select All Files (*.*).
  6. Click the Encoding drop-down list and select ANSI. Click Save.
  7. In the editor area, enter the following 
    (defun c:hello ( / msg)
  (setq msg (getstring T "\nEnter a message: "))
  (alert msg)
)

(prompt "\nAutoLISP Tutorial file loaded.")
(princ) ; Suppress the return value of the prompt function
  8. Click File menu Save.
  9. Close Notepad.
Mac OS
Note: AutoLISP is not available in AutoCAD LT for Mac OS.
  1. In Finder, on the Mac OS menu bar, click Go menu Applications.
  2. In the Applications window, double-click TextEdit.
  3. In TextEdit, on the Mac OS menu bar, click TextEdit menu Preferences.
  4. In the Preferences dialog box, do the following:
    • Under the Format section, click Plain Text.
    • Under the Options section, clear the Check Spelling As You Type and Correct Spelling Automatically check boxes.
    Tip: If needed, a rich text file can be switched to a plain text file by clicking Format menu Make Plain Text on the Mac OS menu bar.
  5. Click the Close button.
  6. On the Mac OS menu bar, click File menu New to create a new document.
  7. With the new document current, on the Mac OS menu bar, click File menu Save.
  8. In the Untitled dialog box, browse to the Documents folder and click New Folder.
    Note: The dialog box must be expanded to see the New Folder button.
  9. In the New Folder dialog box, enter LSP Files and click Create. Select the new folder LSP Files to make sure it is the current folder.
  10. In the Save As text box, enter Create-LSP-Tutorial.lsp.
  11. If checked, clear the If No Extension is Provided, Use ".txt" check box.
  12. Click Save.
  13. In the editor area, enter the following 
    (defun c:hello ( / msg)
  (setq msg (getstring T "\nEnter a message: "))
  (alert msg)
)

(prompt "\nAutoLISP Tutorial file loaded.")
(princ) ; Suppress the return value of the prompt function
  14. On the Mac OS menu bar, click File menu Save.
  15. Quit TextEdit.

Loading an AutoLISP (LSP) File

Here is how to load the Create-LSP-Tutorial.lsp file created under the Creating an AutoLISP (LSP) File section.

Note: AutoLISP is not available in AutoCAD LT for Mac OS.
  1. In AutoCAD, do one of the following:
    • (Windows) On the ribbon, click Manage tab Applications panel Load Application.
    • (Mac OS) On the Mac OS menu bar, click Tools Load Application.
    • At the Command prompt, enter appload.
  2. In the Load/Unload Applications dialog box, browse to the Documents LSP Files folder or the folder in which you stored the Create-LSP-Tutorial.lsp file.
  3. Click Load.
  4. If the File Loading – Security Concern dialog box is displayed, click Load again.
  5. Click Close to return to the application window.
  6. You should see the following message in the Command History window.

    AutoLISP Tutorial file loaded.

  7. At the Command prompt, enter hello.
  8. At the Enter a message: prompt, type a text string and press Enter.

    A message box displays the text string that you entered.

Opening an AutoLISP (LSP) File

Here is how to open the Create-LSP-Tutorial.lsp file that you created under the Creating an AutoLISP (LSP) File section.

Do one of the following:

Related Concepts

Related Reference