Check out Smart::Comments module in Perl [1].

It allows the specially-formatted comments to produce debugging output.

From the synopsis:

    use Smart::Comments;
     
    my $var = suspect_value();
     
    ### $var
     
    ### got: $var
     
    ### Now computing value...
     
    # and when looping:
     
    for my $big_num (@big_nums) {  ### Factoring...      done
        factor($big_num);
    }
     
    while ($error > $tolerance) {  ### Refining--->      done
        refine_approximation()
    }
     
    for (my $i=0; $i<$MAX_INT; $i++) {   ### Working===[%]     done
        do_something_expensive_with($i);
    }

[1] https://metacpan.org/module/Smart::Comments

Noooooo..... Not magic comments.............

Magic comments are evil, the pox of the earth, etc. I have nothing good to say about comments as code. This totally messes up the separation between code and comment.

The typical case where this happens is that the logging was added because of some bug somewhere and this was put in place to figure out what was going on with total. See it as an archaeological record more than anything else ;-)

Hm, my code didn't format as intended. What you wrote is what I meant.