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prolog

uncaught exception: error(existence_error(procedure,not/1),play/0)

I'm trying to understand this code for tic tac toe in prolog. I'm able to compile the code in gprolog,

| ?- ['/**/**/**/tictactoe.pl'].
    compiling /**/**/**/tictactoe.pl for byte code...
    /**/**/**/tictactoe.pl compiled, 142 lines read - 11825 bytes written, 12 ms
    (2 ms) yes

but when I'm executing play, I'm getting the following error:

| ?- play.
uncaught exception: error(existence_error(procedure,not/1),play/0)

As you can see in the last line of the code, play is defined as follows :

play :-not(clear), repeat, getmove, makemove, printboard, done.

And the same code is working perfectly fine in SWI-prolog

When I'm trying to run the prolog file in terminal with either of the following 2 commands

gplc --no-top-level tictactoe.pl

or

gplc  tictactoe.pl

I'm getting the following error:

Undefined symbols for architecture x86_64:
  "predicate(assert/1)", referenced from:
      predicate(getmove/0) in gplcMtKfGg.o
      predicate(makemove/0) in gplcMtKfGg.o
  "predicate(not/1)", referenced from:
      predicate(empty/1) in gplcMtKfGg.o
      predicate(different/2) in gplcMtKfGg.o
      predicate(play/0) in gplcMtKfGg.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
compilation failed
Solution

  • Replacing assert with asserta solved the problem.