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Temporary displays are used by Lisp programs to put output into a buffer and then present it to the user for perusal rather than for editing. Many help commands use this feature.
This function executes forms while arranging to insert any output they print into the buffer named buffer-name, which is first created if necessary, and put into Help mode. Finally, the buffer is displayed in some window, but not selected.
If the forms do not change the major mode in the output buffer, so
that it is still Help mode at the end of their execution, then
with-output-to-temp-buffer makes this buffer read-only at the end,
and also scans it for function and variable names to make them into
clickable cross-references. Voir Tips for Documentation Strings, in particular the item on hyperlinks in
documentation strings, for more details.
The string buffer-name specifies the temporary buffer, which need not
already exist. The argument must be a string, not a buffer. The buffer is
erased initially (with no questions asked), and it is marked as unmodified
after with-output-to-temp-buffer exits.
with-output-to-temp-buffer binds standard-output to the
temporary buffer, then it evaluates the forms in forms. Output using
the Lisp output functions within forms goes by default to that buffer
(but screen display and messages in the echo area, although they are
“output” in the general sense of the word, are not affected).
Voir la section Output Functions.
Several hooks are available for customizing the behavior of this construct; they are listed below.
The value of the last form in forms is returned.
---------- Buffer: foo ----------
This is the contents of foo.
---------- Buffer: foo ----------
(with-output-to-temp-buffer "foo"
(print 20)
(print standard-output))
⇒ #<buffer foo>
---------- Buffer: foo ----------
20
#<buffer foo>
---------- Buffer: foo ----------
|
If this variable is non-nil, with-output-to-temp-buffer calls
it as a function to do the job of displaying a help buffer. The function
gets one argument, which is the buffer it should display.
It is a good idea for this function to run temp-buffer-show-hook just
as with-output-to-temp-buffer normally would, inside of
save-selected-window and with the chosen window and buffer selected.
This normal hook is run by with-output-to-temp-buffer before
evaluating body. When the hook runs, the temporary buffer is
current. This hook is normally set up with a function to put the buffer in
Help mode.
This normal hook is run by with-output-to-temp-buffer after
displaying the temporary buffer. When the hook runs, the temporary buffer
is current, and the window it was displayed in is selected. This hook is
normally set up with a function to make the buffer read only, and find
function names and variable names in it, provided the major mode is Help
mode.
This function momentarily displays string in the current buffer at position. It has no effect on the undo list or on the buffer's modification status.
The momentary display remains until the next input event. If the next input
event is char, momentary-string-display ignores it and
returns. Otherwise, that event remains buffered for subsequent use as
input. Thus, typing char will simply remove the string from the
display, while typing (say) C-f will remove the string from the
display and later (presumably) move point forward. The argument char
is a space by default.
The return value of momentary-string-display is not meaningful.
If the string string does not contain control characters, you can do
the same job in a more general way by creating (and then subsequently
deleting) an overlay with a before-string property. Voir la section Overlay Properties.
If message is non-nil, it is displayed in the echo area while
string is displayed in the buffer. If it is nil, a default
message says to type char to continue.
In this example, point is initially located at the beginning of the second line:
---------- Buffer: foo ---------- This is the contents of foo. ∗Second line. ---------- Buffer: foo ---------- (momentary-string-display "**** Important Message! ****" (point) ?\r "Type RET when done reading") ⇒ t ---------- Buffer: foo ---------- This is the contents of foo. **** Important Message! ****Second line. ---------- Buffer: foo ---------- ---------- Echo Area ---------- Type RET when done reading ---------- Echo Area ---------- |
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Ce document a été généré par Eric Reinbold le 13 Octobre 2007 en utilisant texi2html 1.78.