Support empty ranges in replace-ranges highlighter

2 files changed, 31 insertions, 11 deletions

diff --git a/doc/pages/changelog.asciidoc b/doc/pages/changelog.asciidoc
index 4e706c89..a4ed429b 100644
--- a/doc/pages/changelog.asciidoc
+++ b/doc/pages/changelog.asciidoc
@@ -5,6 +5,8 @@ released versions.
 
 == Development version
 
+* replace-ranges highlighter now support empty ranges
+
 * `%var{...}` now expands to list of strings, `$kak_quoted_...` now work
   as expected with these.
 
diff --git a/doc/pages/options.asciidoc b/doc/pages/options.asciidoc
index d074accf..db070781 100644
--- a/doc/pages/options.asciidoc
+++ b/doc/pages/options.asciidoc
@@ -88,19 +88,37 @@ are exclusively available to built-in options.
 *range-specs*::
     a timestamp (like `%val{timestamp}`,
     see <<expansions#value-expansions,`:doc expansions value-expansions`>>)
-    followed by a list of range descriptors. Each range descriptor must use
-    the syntax `a.b,c.d|string` or `a.b+length|string`, where _a_ is the line
-    containing the first character, _b_ is the number of bytes from the start
-    of the line to the first byte of the first character, _c_ is the line
-    containing the last character, _d_ is the number of bytes from the start of
-    the line to the first byte of the last character, _length_ is the length of
-    the range in bytes and _string_ is an arbitrary string which is associated
-    with the range. All numeric fields are 1-based. When the `update-option` is
-    used on an option of this type, its ranges gets updated according to all the
-    buffer modifications that happened since its timestamp. See
-    <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)
+    followed by a list of range descriptors.
+
+    Each range descriptor must use the syntax `a.b,c.d|string` or
+    `a.b+length|string`, with:
+
+        * _a_ is the line containing the first character
+
+        * _b_ is the number of bytes from the start of the line to the
+        first byte of the first character
+
+        * _c_ is the line containing the last character
+
+        * _d_ is the number of bytes from the start of the line to the
+          first byte of the last character
+
+        * _length_ is the length of the range in bytes, if 0 the range
+          is empty, but still valid.
+
+        * _string_ is an arbitrary string which is associated with
+          the range.
+
+    All numeric fields are 1-based.
+
+    When the `update-option` is used on an option of this type, its
+    ranges gets updated according to all the buffer modifications that
+    happened since its timestamp.
+
     `set -add` appends the new pair to the list
 
+    See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)
+
 *line-specs*::
     a list of a line number and a corresponding flag (`<line>|<flag
     text>`), except for the first element which is just the timestamp