1.11.12.3 Extraction of the atom and comparison to PlAtom

Example:

static PlAtom ATOM_read("read");

PREDICATE(test, 1)
{ PlAtom a1(A1);

  if ( a1 == ATOM_read )
    ...;
}

This approach is basically the same as section 1.11.12.2, but in nested if-then-else the extraction of the atom from the term is done only once.