Re: newbie : elisp - prompt for input

[Kevin Rodgers <ihs_4664@yahoo.com>]

Hadron Quark wrote:
> Kevin Rodgers <ihs_4664@yahoo.com> writes:
> 
>> Hadron Quark wrote:
>>> Is the snippet below the best way to prompt and parse an integer value?
>>>
>>>
>>> (defun count-words(max)
>>>   "count words in buffer"
>>>   (interactive "nMax words to count to:")
>>>   (while (zerop max)
>>>     (setq max (string-to-number(read-string "> 0 please. re-enter:"))))
>> The only thing I see wrong with it is that the check runs outside
>> of the interactive form, and prompts the user (regardless of whether
>> the function was called interactively).
> 
> Youve lost me : what do you mean "outside of the interactive form" - the
> whole function is an interactive form isnt it?

No, the interactive form is exactly that: (interactive "nMax words to 
count to:")

The interactive form is a declaration whose only effect is to bind
the function arguments to values when it's called interactively:
via an input event binding, M-x (execute-extended-command), or the
call-interactively function.

If you type "(count-words 0)" into the *scratch* buffer (without the
quotes) and type `C-x e' or `C-j', you'll be prompted to re-enter MAX
even though you were never prompted in the first place.

-- 
Kevin