&optional
control &rest arguments → generalized-boolean
* yes-or-no-p{
&optional control
&rest arguments → generalized-booleancontrol - a format control.
arguments - format arguments for control.
generalized-boolean - a generalized boolean.
These functions ask a question and parse a response from the user. They return true if the answer is affirmative, or false if the answer is negative.
y-or-n-p is for asking the user a question whose answer is either "yes" or "no." It is intended that the reply require the user to answer a yes-or-no question with a single character.
yes-or-no-p is also for asking the user a question whose answer is either "Yes" or "No." It is intended that the reply require the user to take more action than just a single keystroke, such as typing the full word yes
or no
followed by a newline.
y-or-n-p types out a message (if supplied), reads an answer in some implementation-dependent manner (intended to be short and simple, such as reading a single character such as Y
or N
). yes-or-no-p types out a message (if supplied), attracts the user's attention (for example, by ringing the terminal's bell), and reads an answer in some implementation-dependent manner (intended to be multiple characters, such as YES
or NO
).
If format-control is supplied and not nil, then a fresh-line operation is performed; then a message is printed as if format-control and arguments were given to format. In any case, yes-or-no-p and y-or-n-p will provide a prompt such as ""(Y or N) or ""(Yes or No)
if appropriate.
All input and output are performed using query I/O.
(y-or-n-p "(t or nil) given by")
→(t or nil) given by (Y or N) Y
→(yes-or-no-p "a ~S message" 'frightening)
→a FRIGHTENING message (Yes or No) no
→(y-or-n-p "Produce listing file?")
▷Produce listing file? Please respond with Y or N. n
→
Output to and input from query I/O will occur.
None.
yes-or-no-p and yes-or-no-p do not add question marks to the end of the prompt string, so any desired question mark or other punctuation should be explicitly included in the text query.
\issue{FORMAT-STRING-ARGUMENTS:SPECIFY}