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File compilation example

We'll make a sample program a little bit larger, and then we'll compile it to a file.

Surround the call to format with a call to message-dialog.
The resulting line of code should look like this:
(message-dialog (format nil "Hello, ~A!" my-name))

Notice that when you type the space after the name of the function "message-dialog", a message appears in the bottom of the Fred window. This message area is called the mini-buffer. When you type an open-parenthesis followed by the name of a function followed by a space, Fred displays the argument list of the function in the mini-buffer.

If you want to see what the function message-dialog does, you can get the documentation string for it. To do this, select the text "message-dialog" in the window, or place the cursor inside the text, and press Control-x Control-d. This is the MCL command for bringing up the documentation window.

Figure 2-7 The documentation window

Replace the variable definition with a function definition, including a local variable binding.
The resulting code will look like this:

(defun say-hello ()
  (let ((my-name (get-string-from-user
                  "Please type in your name.")))
    (message-dialog
    (format nil "Hello, ~A!" my-name))))

Compile the function.
You do this by selecting it and choosing Execute Selection from the Lisp menu.
Now try out the function.
Type (say-hello) in the Listener and press Return.

We've now defined a Lisp function which asks the user for their name, and then displays the name along with a greeting in a dialog box. If we want to use this function in a later Lisp session, we'll need to load it after restarting Lisp. To make that loading faster, we'll compile the file containing the function definition.

Save the file.
Choose the Save command from the File menu.
Compile the file.
Choose the Compile File... command from the File menu. MCL will prompt you to choose a file to compile. When you've chosen, it will prompt you to choose a name for the compiled file. Use the name it suggests for the compiled file. MCL will then compile the file.
Quit and restart MCL
Choose the Quit command from the File menu, or call the quit function from the Listener.
Load the file containing the function you've defined.
Choose the Load from the File menu. You will be prompted to choose a file to load. You can choose either the source code file or the compiled file. In general, compiled-files load much more quickly (though with a file of this size, it doesn't make much difference).
Try out the function, to make sure it loaded properly.
Type (say-hello) in the Listener and press Return.
Go back to the source code of the function.
Position the cursor inside the text "say-hello" and press Option-Period. MCL will open the source code file containing the definition (if it is not already open) and it will scroll to the definition.

Gettmg Started with MCL - 19 OCT 1996

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