xdisp.c (set_cursor_from_row): Improve comments.

diff --git a/src/xdisp.c b/src/xdisp.c
index c6ae6ad4c147f9ff29cc4da8a1b43ceef80fde0d..997c76934d431d2422fb16f1f2c37309e1d0deba 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -12606,7 +12606,8 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
            }
          if (INTEGERP (glyph->object) && glyph->charpos < 0)
            --glyph;
-         /* By default, put the cursor on the rightmost glyph.  */
+         /* By default, in reversed rows we put the cursor on the
+            rightmost (first in the reading order) glyph.  */
          for (g = end + 1; g < glyph; g++)
            x += g->pixel_width;
          cursor_x = x;
@@ -12683,7 +12684,16 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
                bpos_covered = bpos_max + XINT (chprop);
                /* If the `cursor' property covers buffer positions up
                   to and including point, we should display cursor on
-                  this glyph.  */
+                  this glyph.  Note that overlays and text properties
+                  with string values stop bidi reordering, so every
+                  buffer position to the left of the string is always
+                  smaller than any position to the right of the
+                  string.  Therefore, if a `cursor' property on one
+                  of the string's characters has an integer value, we
+                  will break out of the loop below _before_ we get to
+                  the position match above.  IOW, integer values of
+                  the `cursor' property override the "exact match for
+                  point" strategy of positioning the cursor.  */
                /* Implementation note: bpos_max == pt_old when, e.g.,
                   we are in an empty line, where bpos_max is set to
                   MATRIX_ROW_START_CHARPOS, see above.  */