20.3 Reading Lisp Objects with the Minibuffer

This section describes functions for reading Lisp objects with the minibuffer.

function read-minibuffer prompt \&optional initial

This function reads a Lisp object using the minibuffer, and returns it without evaluating it. The arguments prompt and initial are used as in read-from-minibuffer.

This is a simplified interface to the read-from-minibuffer function:

(read-minibuffer prompt initial)
≡
(let (minibuffer-allow-text-properties)
  (read-from-minibuffer prompt initial nil t))

Here is an example in which we supply the string "(testing)" as initial input:

(read-minibuffer
 "Enter an expression: " (format "%s" '(testing)))

;; Here is how the minibuffer is displayed:

---------- Buffer: Minibuffer ----------
Enter an expression: (testing)∗
---------- Buffer: Minibuffer ----------

The user can type RET immediately to use the initial input as a default, or can edit the input.

function eval-minibuffer prompt \&optional initial

This function reads a Lisp expression using the minibuffer, evaluates it, then returns the result. The arguments prompt and initial are used as in read-from-minibuffer.

This function simply evaluates the result of a call to read-minibuffer:

(eval-minibuffer prompt initial)
≡
(eval (read-minibuffer prompt initial))

function edit-and-eval-command prompt form

This function reads a Lisp expression in the minibuffer, evaluates it, then returns the result. The difference between this command and eval-minibuffer is that here the initial form is not optional and it is treated as a Lisp object to be converted to printed representation rather than as a string of text. It is printed with prin1, so if it is a string, double-quote characters (‘"’) appear in the initial text. See Output Functions.

In the following example, we offer the user an expression with initial text that is already a valid form:

(edit-and-eval-command "Please edit: " '(forward-word 1))

;; After evaluation of the preceding expression,
;;   the following appears in the minibuffer:

---------- Buffer: Minibuffer ----------
Please edit: (forward-word 1)∗
---------- Buffer: Minibuffer ----------

Typing RET right away would exit the minibuffer and evaluate the expression, thus moving point forward one word.