[Emacs-diffs] Changes to emacs/lispref/text.texi

[Kim F . Storm]

Index: emacs/lispref/text.texi
diff -c emacs/lispref/text.texi:1.82 emacs/lispref/text.texi:1.83
*** emacs/lispref/text.texi:1.82        Thu Jan  6 17:44:55 2005
--- emacs/lispref/text.texi     Tue Jan 11 00:12:09 2005
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*** 2431,2436 ****
--- 2431,2438 ----
                               only when text is examined.
  * Clickable Text::         Using text properties to make regions of text
                               do something when you click on them.
+ * Enabling Mouse-1 to Follow Links::
+                            How to make @key{mouse-1} follow a link.
  * Fields::                 The @code{field} property defines
                               fields within the buffer.
  * Not Intervals::        Why text properties do not use
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*** 3388,3393 ****
--- 3390,3499 ----
  global definition) remains available for the rest of the text in the
  buffer.
  
+ @node Enabling Mouse-1 to Follow Links
+ @subsection Enabling Mouse-1 to Follow Links
+ @cindex follow links
+ 
+   Traditionally, Emacs uses a @key{mouse-1} click to set point and a
+ @key{mouse-2} click to follow a link, whereas most other applications
+ use a @key{mouse-1} click for both purposes, depending on whether you
+ click outside or inside a link.
+ 
+   Starting with Emacs release 21.4, the user visible behaviour of a
+ @key{mouse-1} click on a link has been changed to match this
+ context-sentitive dual behaviour.  The user can customize this
+ behaviour through the variable @code{mouse-1-click-follows-link}.
+ 
+   However, at the Lisp level, @key{mouse-2} is still used as the
+ action for the clickable text corresponding to the link, and the
+ clickable text must be explicitly marked as a link for a @key{mouse-1}
+ click to follow the link.
+ 
+   There are several methods that can be used to identify a clickable
+ text as a link:
+ 
+ @table @asis
+ @item follow-link property
+ 
+   If the clickable text has a non-nil @code{follow-link} text or overlay
+ property, the value of that property determines what to do.
+ 
+ @item follow-link event
+ 
+   If there is a binding for the @code{follow-link} event, either on
+ the clickable text or in the local keymap, the binding of that event
+ determines whether the mouse click position is inside a link:
+ 
+ @table @asis
+ @item mouse-face
+ 
+   If the binding is @code{mouse-face}, the mouse click position is
+ inside a link if there is a non-nil @code{mouse-face} property at
+ that position.  A value of @code{t} is used to determine what to do next.
+ 
+ For example, here is how @key{mouse-1} are setup in info mode:
+ 
+ @example
+ (define-key Info-mode-map [follow-link] 'mouse-face)
+ @end example
+ 
+ @item a function
+ 
+   If the binding is a function, @var{func}, the mouse click position,
+ @var{pos}, is inside a link if the call @code{(@var{func} @var{pos})}
+ returns address@hidden  The return value from that call determines
+ what to do next.
+ 
+ For example, here is how pcvs enables @key{mouse-1} on file names only:
+ 
+ @example
+ (define-key map [follow-link]
+   (lambda (pos)
+     (if (eq (get-char-property pos 'face) 'cvs-filename-face) t)))
+ @end example
+ 
+ @item anthing else
+ 
+   If the binding is anything else, the binding determines what to do.
+ @end table
+ 
+ @end table
+ 
+ @noindent
+ The resulting value determined above is interpreted as follows:
+ 
+ @table @asis
+ @item a string
+ 
+   If the value is a string, the @key{mouse-1} event is translated into
+ the first character of the string, i.e. the action of the @key{mouse-1}
+ click is the local or global binding of that character.
+ 
+ @item a vector
+ 
+   If the value is is a vector, the @key{mouse-1} event is translated
+ into the first element of that vector, i.e. the action of the
+ @key{mouse-1} click is the local or global binding of that event.
+ 
+ @item anthing else
+ 
+   For any other non-nil valule, the @key{mouse-1} event is translated
+ into a @key{mouse-2} event at the same position.
+ @end table
+ 
+   To use @key{mouse-1} on a button defined with @code{define-button-type},
+ give the button a @code{follow-link} property with a value as
+ specified above to determine how to follow the link.
+ 
+   To use @key{mouse-1} on a widget defined with @code{define-widget},
+ give the widget a @code{:follow-link} property with a value
+ as specified above to determine how to follow the link.
+ 
+ @defun mouse-on-link-p pos
+ @tindex mouse-on-link-p
+ Return address@hidden if @var{pos} is on a link in the current buffer.
+ @end defun
+ 
  @node Fields
  @subsection Defining and Using Fields
  @cindex fields