Commit f7a7f4eb authored by Richard M. Stallman's avatar Richard M. Stallman

(Overlay Properties): Explain nil as priority. Explain that conflicts

are unpredictable if not resolved by priorities.
parent 16635351
2007-10-01 Richard Stallman <rms@gnu.org>
* display.texi (Overlay Properties): Explain nil as priority.
Explain that conflicts are unpredictable if not resolved by
priorities.
2007-09-23 Richard Stallman <rms@gnu.org>
* macros.texi (Backquote): Minor clarification.
......
......@@ -1291,6 +1291,11 @@ while moving an overlay or changing its properties does not. Unlike
text property changes, overlay property changes are not recorded in
the buffer's undo list.
Since more than one overlay can specify a property value for the
same character, Emacs lets you specify a priority value of each
overlay. You should not make assumptions about which overlay will
prevail when there is a conflict and they have the same priority.
These functions read and set the properties of an overlay:
@defun overlay-get overlay prop
......@@ -1321,13 +1326,16 @@ of them:
@item priority
@kindex priority @r{(overlay property)}
This property's value (which should be a nonnegative integer number)
determines the priority of the overlay. The priority matters when two
or more overlays cover the same character and both specify the same
property; the one whose @code{priority} value is larger takes priority
over the other. For the @code{face} property, the higher priority
value does not completely replace the other; instead, its face
attributes override the face attributes of the lower priority
@code{face} property.
determines the priority of the overlay. No priority, or @code{nil},
means zero.
The priority matters when two or more overlays cover the same
character and both specify the same property; the one whose
@code{priority} value is larger overrides the other. For the
@code{face} property, the higher priority overlay's value does not
completely override the other value; instead, its face attributes
override the face attributes of the lower priority @code{face}
property.
Currently, all overlays take priority over text properties. Please
avoid using negative priority values, as we have not yet decided just
......
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