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| -rw-r--r-- | lispref/text.texi | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/lispref/text.texi b/lispref/text.texi index d625e5e2156..6153bdb69f1 100644 --- a/lispref/text.texi +++ b/lispref/text.texi @@ -965,12 +965,22 @@ This function places a boundary element in the undo list. The undo command stops at such a boundary, and successive undo commands undo to earlier and earlier boundaries. This function returns @code{nil}. -The editor command loop automatically creates an undo boundary between -keystroke commands. Thus, each undo normally undoes the effects of one -command. Calling this function explicitly is useful for splitting the -effects of a command into more than one unit. For example, -@code{query-replace} calls this function after each replacement so that -the user can undo individual replacements one by one. +The editor command loop automatically creates an undo boundary before +each key sequence is executed. Thus, each undo normally undoes the +effects of one command. Self-inserting input characters are an +exception. The command loop makes a boundary for the first such +character; the next 19 consecutive self-inserting input characters do +not make boundaries, and then the 20th does, and so on as long as +self-inserting characters continue. + +All buffer modifications add a boundary whenever the previous undoable +change was made in some other buffer. This way, a command that modifies +several buffers makes a boundary in each buffer it changes. + +Calling this function explicitly is useful for splitting the effects of +a command into more than one unit. For example, @code{query-replace} +calls @code{undo-boundary} after each replacement, so that the user can +undo individual replacements one by one. @end defun @defun primitive-undo count list |