function evaluated, but cannot execute

function evaluated, but cannot execute

[ken]

Testing little function to learn from...

(defun my-prepend-to-file ()
  "Prepend some hard-coded text to specified file."
  (let ((oldbuf (current-buffer)))
    (save-current-buffer
      (set-buffer (get-buffer-create "/home/zl/tmp/test.html"))
      (insert "\n\nText inserted by my-prepend-to-file.\n\n"))))

I evaluate this function.  No problem.

I do "C-h f my-prepend-to-file RET", emacs displays in the other window:

my-prepend-to-file is a Lisp function.

(my-prepend-to-file)

Prepend some hard-coded text to specified file.

[back]

But when I do "M-x my-prepend-to-file RET", emacs responds "[No match]".
 So what's wrong?


tia,
ken


-- 
Anything is easy if you know how to do it.

RE: function evaluated, but cannot execute

[Drew Adams]

> But when I do "M-x my-prepend-to-file RET", emacs responds 
> "[No match]".  So what's wrong?

This might be the #1 FAQ. You need an `interactive' spec to turn your function
into a command (interactive function).  See the Elisp manual, node `Using
Interactive'.

Consider also reading the integrated manual "An Introduction to Programming in
Emacs Lisp" (Emacs Lisp Intro). It will help greatly with things like this.

Re: function evaluated, but cannot execute

[PJ Weisberg]

On Tuesday, April 26, 2011, ken <gebser@mousecar.com> wrote:
> Testing little function to learn from...
>
> (defun my-prepend-to-file ()
>   "Prepend some hard-coded text to specified file."
>   (let ((oldbuf (current-buffer)))
>     (save-current-buffer
>       (set-buffer (get-buffer-create "/home/zl/tmp/test.html"))
>       (insert "\n\nText inserted by my-prepend-to-file.\n\n"))))
>
> I evaluate this function.  No problem.
>
> I do "C-h f my-prepend-to-file RET", emacs displays in the other window:
>
> my-prepend-to-file is a Lisp function.
>
> (my-prepend-to-file)
>
> Prepend some hard-coded text to specified file.
>
> [back]
>
> But when I do "M-x my-prepend-to-file RET", emacs responds "[No match]".
>  So what's wrong?
>
>
> tia,
> ken

Right after the docstring, put (interactive).  (If the function took
arguments you would have to put more stuff inside the 'interactive'
form, but that's enough to be able to call it from M-x or with a
keybinding.

And you want 'find-file' or 'find-file-noselect' instead of 'get-buffer-create'.

-- 

-PJ

Re: function evaluated, but cannot execute

[ken]

On 04/26/2011 05:48 PM PJ Weisberg wrote:
> On Tuesday, April 26, 2011, ken <gebser@mousecar.com> wrote:
>> Testing little function to learn from...
>>
>> (defun my-prepend-to-file ()
>>   "Prepend some hard-coded text to specified file."
>>   (let ((oldbuf (current-buffer)))
>>     (save-current-buffer
>>       (set-buffer (get-buffer-create "/home/zl/tmp/test.html"))
>>       (insert "\n\nText inserted by my-prepend-to-file.\n\n"))))
>>
>> I evaluate this function.  No problem.
>>
>> I do "C-h f my-prepend-to-file RET", emacs displays in the other window:
>>
>> my-prepend-to-file is a Lisp function.
>>
>> (my-prepend-to-file)
>>
>> Prepend some hard-coded text to specified file.
>>
>> [back]
>>
>> But when I do "M-x my-prepend-to-file RET", emacs responds "[No match]".
>>  So what's wrong?
>>
>>
>> tia,
>> ken
> 
> Right after the docstring, put (interactive).  (If the function took
> arguments you would have to put more stuff inside the 'interactive'
> form, but that's enough to be able to call it from M-x or with a
> keybinding.
> 
> And you want 'find-file' or 'find-file-noselect' instead of 'get-buffer-create'.
> 

Thanks for the tip.  Yeah, for some reason get-buffer-create fails, does
nothing.  Replacing it with find-file or *-select works fine.  Strange
because I scarfed the code from an emacs Info page and the *Help* page
says get-buffer-create will accept a file as an arg.  I'll just say,
"That's perplexing."

thanks++,
ken


-- 
Anything is easy if you know how to do it.