Re: debugging

[Adam Russell]

Yes, the usual trace/0 and spy points abilities are available http://www.gprolog.org/manual/html_node/gprolog013.html

Here is a simple example

$ gprolog

GNU Prolog 1.4.5 (32 bits)

Compiled Dec  3 2020, 00:37:14 with gcc

By Daniel Diaz

Copyright (C) 1999-2020 Daniel Diaz

| ?- [user].

compiling user for byte code...

something(A):- something_else(A).

something_else(A):- A is 2 + 2.

user compiled, 2 lines read - 414 bytes written, 19475 ms

(10 ms) yes

| ?- spy(something_else).

Spypoint placed on something_else/1

The debugger will first leap -- showing spypoints (debug)

(1 ms) yes

{debug}

| ?- something(X).

 +    2    2  Call: something_else(_23) ?

      3    3  Call: _23 is 2+2 ?

      3    3  Exit: 4 is 2+2 ?

 +    2    2  Exit: something_else(4) ?

      1    1  Exit: something(4) ?

X = 4

(1 ms) yes

{debug}