A source_location denotes a location in a sourcefile.
They are created by the compiler and used by this manual tool to find
the sources for classes and methods.
If possible, the filename must be absolute, so the sources can be found regardless of the current directory.
A value @nil for the line_no implies the line number is not known. The Prolog defined class compiler uses the predicate source_location/2 to find out about the location from which the last term presented to term_expansion/2 was read. The line-numbers for system defined classes are determined via the EMACS tag-file TAGS in the PCE source directory.
<-file_name
is absolute, returns this value. Otherwise prepend pce<-home/src/.