PG.pl uses the round function without explicitly loading a package that contains it.

[dlglin]

Here is a MWE:

DOCUMENT();

loadMacros(
    "PG.pl",
    "PGbasicmacros.pl",
    "PGML.pl",
);

$ans = List("1,2");

BEGIN_PGML
Enter [`1,2`]: [_]{$ans}
END_PGML
ENDDOCUMENT();

Enter "1" in the answer blank and you get the following warning message, and the feedback is not shown for the answer.

ERRORS from post processing PG text:
Undefined subroutine &main::round called at [PG]/macros/PG.pl line 1097

This is because the round function is defined in PGauxiliaryFunctions.pl, which is not loaded by this problem.

This could be solved by having PG.pl load PGauxiliaryFunctions.pl, but it seems wrong to have the core PG macro depend on other macro files.