// adding marker 1 at line 4...
$scintilla->marker_add(4, 1);

// adding marker 1 at line 6...
$scintilla->marker_add(6, 1);

// adding marker 1 at line 8...
$scintilla->marker_add(8, 1);

// adding marker 2 at line 5...
$scintilla->marker_add(5, 2);

// removes all markers "1"...
$scintilla->marker_delete_all(1);