Operand evaluation order

[Ralph Grove]

I'm trying to determine how Perl evaluates operands for expressions. I 
expected the following code to output 3, 4, and 5, as it would if 
executed as a C++ or Java program. The actual output that I get 
(v5.16.2), however, is 4, 4, and 5. This leads me to believe that 
operand evaluation is either non-deterministic and compiler-dependent, 
or it's simply broken.

The Perl documentation discusses operator evaluation, but doesn't 
directly address operand evaluation order. Does anyone know of a good 
resource for this information?

Thanks,
Ralph



sub doit {
  return ++$g ;
}

$g = 0;
my $sum = $g + doit() + doit();
print "$sum \n";

$g = 0;
$sum = doit() + $g + doit();
print "$sum \n";

$g = 0;
$sum = doit() + doit() + $g;
print "$sum \n";



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