built-in shelf
 #log is one of the built-in string sinks, and the standard log stream for OmniMark. OmniMark
        places all errors and informative messages to #log, but it will accept user-defined strings as well.
      
 If no -log nor -alog option is given on the command line, #log is equivalent to #error.
      
 The following code illustrates the use of #log for reporting errors:
        
global integer list-size process local integer items variable ; ... using output as #log do when number of items != list-size output "The list contains the wrong number of items:" || " list-size = " || "d" % list-size || ", but list-items has " || "d" % number of items || " item(s).%n" halt with 2 ; signals an error condition while stopping done
 This sink is always unbuffered and in text-mode and cannot be declared otherwise. In any
        program that uses referents, #log is treated as if it were opened with
        referents-displayed.