Tests/RunCMake/list/SORT-COMPARATOR-DuplicateOption.cmake

function(my_cmp a b out)
  if("${a}" STRLESS "${b}")
    set(${out} TRUE PARENT_SCOPE)
  else()
    set(${out} FALSE PARENT_SCOPE)
  endif()
endfunction()

set(mylist c a b)
list(SORT mylist COMPARATOR my_cmp COMPARATOR my_cmp)