/usr/lib/swipl/library/test_cover.pl
AllApplicationManualNameSummaryHelp

 show_coverage(:Goal) is semidet
 show_coverage(:Goal, +Options) is semidet
show_coverage(:Goal, +Modules:list(atom)) is semidet
Report on coverage by Goal. Goal is executed as in once/1. Options processed:
modules(+Modules)
Provide a detailed report on Modules. For backwards compatibility this is the same as providing a list of modules in the second argument.
annotate(+Bool)
Create an annotated file for the detailed results. This is implied if the ext or dir option are specified.
ext(+Ext)
Extension to use for the annotated file. Default is `.cov`.
dir(+Dir)
Dump the annotations in the given directory. If not given, the annotated files are created in the same directory as the source file. Each clause that is related to a physical line in the file is annotated with one of:
###Clause was never executed.
++NClause was entered N times and always succeeded
--NClause was entered N times and never succeeded
+N-MClause has succeeded N times and failed M times
+N*MClause was entered N times and succeeded M times

All call sites are annotated using the same conventions, except that --- is used to annotate subgoals that were never called.

line_numbers(Boolean)
If true (default), add line numbers to the annotated file.
color(Boolean)
Controls using ANSI escape sequences to color the output in the annotated source. Default is true.