CODEWITHSUNDEEP
prologgnu
user506912
user506912

Reputation: 69

GNU prolog, print to console?

I'm having a very hard time debugging my code with gprolog, does anyone know how to print the value of a variable to the console after I've compiled it? I've tried using print, write and trace within my code but none have had any consequence, not even an error. Please help!

Upvotes: 2

Views: 1749

Answers (1)

CapelliC
CapelliC

Reputation: 60004

session example: start gprolog in console

GNU Prolog 1.3.0
By Daniel Diaz
Copyright (C) 1999-2007 Daniel Diaz
| ?- [user].
compiling user for byte code...
test_pos(P) :- P > 0 -> true ; format('~w is invalid', [P]).

user compiled, 2 lines read - 762 bytes written, 180411 ms

(8 ms) yes
| ?- trace,test_pos(-3).
The debugger will first creep -- showing everything (trace)
      1    1  Call: test_pos(-3) ? 
      2    2  Call: -3>0 ? 
      2    2  Fail: -3>0 ? 
      2    2  Call: format('~w is invalid',[-3]) ? 
-3 is invalid
      2    2  Exit: format('~w is invalid',[-3]) ? 
      1    1  Exit: test_pos(-3) ? 

yes
{trace}
| ?-

before the message user compiled,... I entered Ctrl-D to force compilation

HTH

Upvotes: 1

Related Questions