User input/Graphical: Difference between revisions

=={{header|Common Lisp}}==

{{libheader|CAPI}}

{{works with|LispWorks}}

Prompt for a string:

<lang lisp>(capi:prompt-for-string "Enter a string:")</lang>

Repeatedly prompt for an integer until either the user presses 'Cancel' (instead of 'OK') or the integer is 75,000.

<lang lisp>(do ((number 0) (okp t))

((or (not okp) (= 75000 number)))

(multiple-value-setq (number okp)

(capi:prompt-for-integer "Enter an integer:")))</lang>

Alternatively, display a prompt where the 'OK' button will not be enabled until the input is 75,000:

<lang lisp>(capi:prompt-for-integer "Enter an integer:"

:ok-check #'(lambda (n) (= n 75000)))</lang>

And a version which displays one prompt with an area for a string and an area for an integer, and only enables the 'OK' button when the integer is 75,000.

First, define an interface with the text-areas:

<lang lisp>(capi:define-interface string/integer-prompt () ()

(:panes

(string-pane

capi:text-input-pane

:title "Enter a string:")

(integer-pane

capi:text-input-pane

:title "Enter an integer:"

:change-callback :redisplay-interface))

(:layouts

(main

capi:column-layout

'(string-pane integer-pane))))</lang>

Then a function to extract the string and integer:

<lang lisp>(defun string/integer-prompt-value (pane)

(with-slots (string-pane integer-pane) pane

(let* ((string (capi:text-input-pane-text string-pane))

(integer-string (capi:text-input-pane-text integer-pane))

(integer (when (every 'digit-char-p integer-string)

(parse-integer integer-string :junk-allowed t))))

(values (cons string integer)))))</lang>

Finally, display a prompt using the defined function to extract a value, and an 'ok-check' to ensure that the integer value is 75,000.

<lang lisp>(defun do-prompting ()

(capi:popup-confirmer

(make-instance 'string/integer-prompt)

"Enter some values:"

:value-function 'string/integer-prompt-value

:ok-check #'(lambda (result) (eql (cdr result) 75000))))</lang>