How to prompt for string?

How to prompt for string?

[jacksneckhurts]

I'm trying to teach myself emacs Lisp, but can't figure out how to
prompt for a string. I found the "read-key-sequence-vector" function,
but that only takes in one character. Does anyone know how to prompt
for a string? Thanks.

Re: How to prompt for string?

[Pascal Bourguignon]

jacksneckhurts@yahoo.com writes:

> I'm trying to teach myself emacs Lisp, but can't figure out how to
> prompt for a string. I found the "read-key-sequence-vector" function,
> but that only takes in one character. Does anyone know how to prompt
> for a string? Thanks.

I don't know.  Or do you think I'm a super genius?
Let's see: 

M-x apropos RET read RET
C-v
C-s read-string RET C-s C-s C-s

Yep, seems like this could be useful:

read-string
  Function: Read a string from the minibuffer, prompting with string PROMPT.

C-h f read-string RET

Yep, sounds promizing.


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/

"You cannot really appreciate Dilbert unless you read it in the
original Klingon"

Re: How to prompt for string?

[jacksneckhurts]

You are a genius! Now I can conquor the world.

I've been beating my head against my computer trying to find that
function. Thanks!

RE: How to prompt for string?

[Dirk-Jan.Binnema]

You can use 'interactive', which uses to some 'magic' chars to specify
what to prompt for.

  (interactive "r\nsSummary:")

The 'r' will get you the region (begin and and), and 's' will get you
a string. The function with the interactive when then be called as
if it were called with these parameters.

My Example:

;; remove parts of old email, and replace with [snip: ... ]
(defun snip-mail (r-begin r-end summary)
  (interactive "r\nsSummary:")
  (let ((line-num (count-lines r-begin r-end)))
    (delete-region r-begin r-end)
    (insert (format "[snip%s (%d line%s)]\n" 
	      (if (= 0 (length summary)) "" (concat ": " summary))
	      line-num 
	      (if (= line-num 1) "" "s")))))


Best wishes,
Dirk.

Re: How to prompt for string?

[Kevin Rodgers]

jacksneckhurts@yahoo.com wrote:
> I'm trying to teach myself emacs Lisp, but can't figure out how to
> prompt for a string. I found the "read-key-sequence-vector" function,
> but that only takes in one character. Does anyone know how to prompt
> for a string? Thanks.

,----[ C-h f read-string RET ]
| read-string is a built-in function.
| (read-string PROMPT &optional INITIAL-INPUT HISTORY DEFAULT-VALUE 
INHERIT-INPUT-METHOD)
|
| Read a string from the minibuffer, prompting with string PROMPT.
| If non-nil, second arg INITIAL-INPUT is a string to insert before reading.
| The third arg HISTORY, if non-nil, specifies a history list
|   and optionally the initial position in the list.
| See `read-from-minibuffer' for details of HISTORY argument.
| Fourth arg DEFAULT-VALUE is the default value.  If non-nil, it is used
|  for history commands, and as the value to return if the user enters
|  the empty string.
| Fifth arg INHERIT-INPUT-METHOD, if non-nil, means the minibuffer inherits
|  the current input method and the setting of enable-multibyte-characters.
`----

-- 
Kevin Rodgers

Re: How to prompt for string?

[Kevin Rodgers]

jacksneckhurts@yahoo.com wrote:
> You are a genius! Now I can conquor the world.

Calm down, friend.

> I've been beating my head against my computer trying to find that
> function. Thanks!

In the Emacs Lisp manual, `i prompt' takes you directly to the Using
Interactive node, which you should read.  That node has this example:

           (interactive
            (list (region-beginning) (region-end)
                  (read-string "Foo: " nil 'my-history)))

The Using Interactive node ought to have a link to the Minibuffers
node, which I'll report as a bug.  In the meantime, read that section
as well -- I think you'll be impressed.

-- 
Kevin Rodgers

Re: How to prompt for string?

[Peter Dyballa]

Am 17.02.2006 um 05:58 schrieb jacksneckhurts@yahoo.com:

> I'm trying to teach myself emacs Lisp, but can't figure out how to
> prompt for a string. I found the "read-key-sequence-vector" function,
> but that only takes in one character. Does anyone know how to prompt
> for a string?

Yes, there seem to be a few! I remember that calendar prompts me a  
few times when I want to go to some date. And there are these  
functions to change an encoding, C-x RET f for example. Let's see how  
they do it!

C-h k C-x RET f opens a *Help* buffer with a hyper link to mule.el. I  
follow it. Oufff, it opens in another window! I do not need to  
remember the function's name! Oh -- the cursor is already positioned  
at the function's start ... shall I manage to remember this  
behaviour? But, what is a life without constant sorrows?! I'm glad  
that I've chosen a bad example: no obvious output or input, but ...  
it's prompting me with "Coding system for saving file (default nil):  
" -- let's search for this sentence! Ah, there it is -- the first  
line of code of this function set-buffer-file-coding-system, very  
strange:

   (interactive "zCoding system for saving file (default nil): \nP")


OK, that's one guess. Let's see how a veteran does it in Calendar!   
(interactive (list (calendar-read-date))) -- a function in  
calendar.el. Hey, GNU Emacs even takes me to my private copy with  
German text! Here two functions, calendar-read and completing-read  
are doing the job of prompting, while taking the first argument as  
the prompt's text. The first one uses (read-minibuffer prompt initial- 
contents), the latter uses a function in `C source code'. (completing- 
read PROMPT TABLE &optional PREDICATE REQUIRE-MATCH INITIAL-INPUT  
HIST DEF INHERIT-INPUT-METHOD). Aha.


Two "applications" and three ways to prompt for an input! That's  
efficiency.

--
Greetings

   Pete

Got Mole problems?
Call Avogadro 6.02 x 10^23

RE: How to prompt for string?

[Drew Adams]

Others have pointed you to the doc and various functions that prompt for and
read a string. To find lots of functions that read input (including
strings), use `M-x apropos string'.

Think too about the nature of the string - is it arbitrary? There are
functions to read strings that represent various objects, such as numbers.

An important consideration is whether the string be is restricted to a given
candidate set of strings. Or, can it be arbitrary yet there exists a useful
set of candidate "suggestions"?

If there is some notion of a set of candidate strings, even if they are only
suggestions and other strings are also accepted, then consider using
function `completing-read', which prompts and reads a string allowing users
to complete partial input against matching candidates (using TAB).

For strings that represent file and directory names, a similar,
read-a-string-with-completion function is `read-file-name'.