The expressions in SpecList are all of the form name/arity.
Note that unskipped/1 is superseded by the predicate set_flag(Proc, skip, off), which sets the procedure Proc to be unskipped.
Success: [eclipse]: [user], skipped p/0. q. p :- q. user compiled 60 bytes in 0.00 seconds yes. [eclipse]: trace. Debugger switched on - creep mode yes. [eclipse]: p. S (1) 0 CALL p (dbg)?- creep S (1) 0 EXIT p (dbg)?- creep yes. [eclipse]: unskipped p/0. yes. [eclipse]: p. (1) 0 CALL p (dbg)?- creep (2) 1 CALL q (dbg)?- creep (2) 1 EXIT q (dbg)?- creep (1) 0 EXIT p (dbg)?- creep yes. Error: unskipped Proc/1. (Error 4). unskipped write(Term)/1. (Error 5). unskipped do. (Error 5). unskipped n/1. (Error 60).