C/C++

What does the following C/C++ construction do?


compM<ListM>()[ makePair[X,Y] | X<=list_with(1,2), guard[true],
          Y<=list_with(3,4), guard[ (Y %divides% X) %equal% 3 ] ] ]

>>8
Only an autist/obsessive-compulsive/neurotic becomes distracted by the gimmicks in C++, just like only the autist/obsessive-compulsive/neurotic becomes preoccupied with alphabetically sorting the soup cans in his cupboard.