diff --git a/kitty/line.c b/kitty/line.c
index eb952bb18..eac42f392 100644
--- a/kitty/line.c
+++ b/kitty/line.c
@@ -708,6 +708,7 @@ apply_marker(Marker *marker, Line *line, const PyObject *text) {
     }
     while(x < line->xnum) line->gpu_cells[x++].attrs &= ATTRS_MASK_WITHOUT_MARK;
     Py_DECREF(iter);
+#undef INCREMENT_MATCH_POS
 }
 
 void
diff --git a/kitty/marks.py b/kitty/marks.py
new file mode 100644
index 000000000..168c37481
--- /dev/null
+++ b/kitty/marks.py
@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPLv3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
+
+import re
+from ctypes import c_void_p, cast, c_uint, POINTER
+
+
+pointer_to_uint = POINTER(c_uint)
+
+
+def null_marker(*a):
+    return iter(())
+
+
+def get_output_variables(left_address, right_address, color_address):
+    return (
+        cast(c_void_p(left_address, pointer_to_uint)).contents,
+        cast(c_void_p(right_address, pointer_to_uint)).contents,
+        cast(c_void_p(color_address, pointer_to_uint)).contents,
+    )
+
+
+def marker_from_regex(expression, color):
+    color = max(1, min(color, 3))
+    pat = re.compile(expression)
+
+    def marker(text, left_address, right_address, color_address):
+        left, right, colorv = get_output_variables(left_address, right_address, color_address)
+        colorv.value = color
+        for match in pat.finditer(text):
+            left.value = match.start()
+            right.value = match.end()
+            yield
+
+    return marker
+
+
+def marker_from_text(expression, color):
+    return marker_from_regex(re.escape(expression), color)
+
+
+def marker_from_function(func):
+    def marker(text, left_address, right_address, color_address):
+        left, right, colorv = get_output_variables(left_address, right_address, color_address)
+        for (l, r, c) in func(text):
+            left.value = l
+            right.value = r
+            colorv.value = c
+            yield
+
+    return marker