E1:     C1  1 CALL pred interpreter.main/2-0 (det) interpreter.m:34
mdb> echo on
Command echo enabled.
mdb> context none
Contexts will not be printed.
mdb> register --quiet
mdb> 12 step
Pure Prolog Interpreter.

Consulting file `interpreter.m'...
      E2:     C2  5 SWTC pred interpreter.consult_until_eof_2/5-0 (det) s3;
mdb> vars
        1 HeadVar__1
        2 HeadVar__2
        3 DCG_0 (arg 4)
mdb> print *
       HeadVar__1             	term(varset(var_supply(0), empty, empty), functor(atom(".-"), [|](functor/3, []), context("interpreter.m", 22)))
       HeadVar__2             	[]
       DCG_0 (arg 4)          	state('<<c_pointer>>')
mdb> goto 35
      E3:     C3 12 CALL pred interpreter.database_assert_clause/4-0 (det)
mdb> print *
       Database (arg 1)       	[|](clause(varset(var_supply/1, empty, empty), functor(atom/1, [|]/2, context/2), functor(atom/1, [], context/2)), [|](clause(varset/3, functor/3, functor/3), [|](clause/3, [])))
       VarSet (arg 2)         	varset(var_supply(0), empty, empty)
       Term (arg 3)           	functor(atom(".-"), [|](functor(atom/1, [|]/2, context/2), []), context("interpreter.m", 26))
mdb> finish -a
      E4:     C3 12 COND pred interpreter.database_assert_clause/4-0 (det) ?;
      E5:     C3 12 ELSE pred interpreter.database_assert_clause/4-0 (det) e;
      E6:     C3 12 EXIT pred interpreter.database_assert_clause/4-0 (det)
mdb> print *
       Database (arg 1)       	[|](clause(varset(var_supply/1, empty, empty), functor(atom/1, [|]/2, context/2), functor(atom/1, [], context/2)), [|](clause(varset/3, functor/3, functor/3), [|](clause/3, [])))
       VarSet (arg 2)         	varset(var_supply(0), empty, empty)
       Term (arg 3)           	functor(atom(".-"), [|](functor(atom/1, [|]/2, context/2), []), context("interpreter.m", 26))
       HeadVar__4             	[|](clause(varset(var_supply/1, empty, empty), functor(atom/1, [|]/2, context/2), functor(atom/1, [], context/2)), [|](clause(varset/3, functor/3, functor/3), [|](clause/3, [|]/2)))
mdb> 
      E7:     C4 12 CALL pred interpreter.consult_until_eof/4-0 (det)
mdb> finish -n
      E8:     C4 12 EXIT pred interpreter.consult_until_eof/4-0 (det)
mdb> 
      E9:     C5 11 EXIT pred interpreter.consult_until_eof_2/5-0 (det)
mdb> 
     E10:     C6 10 EXIT pred interpreter.consult_until_eof/4-0 (det)
mdb> continue
?-