Introduce new variable mode-line-compact

* doc/lispref/modes.texi (Mode Line Basics): Document it (bug#34476).

* src/xdisp.c (display_mode_line): Use it.
(syms_of_xdisp): New variable mode-line-compact.

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/lispref/modes.texi b/doc/lispref/modes.texi
index 675aeec8a5f..40edc90a6af 100644
--- a/doc/lispref/modes.texi
+++ b/doc/lispref/modes.texi
@@ -1930,6 +1930,15 @@ This function also forces an update of the menu bar and frame title.
 color using the face @code{mode-line}.  Other windows' mode lines appear
 in the face @code{mode-line-inactive} instead.  @xref{Faces}.
 
+@vindex mode-line-compact
+  Some modes put a lot of data in the mode line, pushing elements at
+the end of the mode line off to the right.  Emacs can ``compress'' the
+mode line if the @code{mode-line-compact} variable is non-@code{nil}
+by turning stretches of spaces into a single space.  If this variable
+is @code{long}, this is only done when the mode line is wider than the
+currently selected window.  This variable can be buffer-local to only
+compress mode-lines in certain buffers.
+
 @node Mode Line Data
 @subsection The Data Structure of the Mode Line
 @cindex mode line construct