use overload {
# . . . other operators
'atan2' =>      sub { atan2($_[0]->numify(),$_[1]) }, 
# . . . the rest of them
};

##</code><code>##

--- BigInt.pm~	Sat Jan  1 10:57:35 2005
+++ BigInt.pm	Sun Jan 23 22:04:36 2005
@@ -75,7 +75,9 @@
 'cos'  =>      sub { cos($_[0]->numify()) }, 
 'sin'  =>      sub { sin($_[0]->numify()) }, 
 'exp'  =>      sub { exp($_[0]->numify()) }, 
-'atan2' =>     sub { atan2($_[0]->numify(),$_[1]) }, 
+'atan2' =>     sub { $_[2] ?
+                     atan2($_[1],$_[0]->numify()) :
+                     atan2($_[0]->numify(),$_[1]) }, 
 
# are not yet overloadable
#'hex'  =>      sub { print "hex"; $_[0]; }, 

##</code><code>##

--- fallback.t~	Thu Dec 11 14:17:58 2003
+++ fallback.t	Sun Jan 23 22:36:17 2005
@@ -28,7 +28,7 @@
     }
   print "# INC = @INC\n";
 
-  plan tests => 8;
+  plan tests => 9;
   }
 
 # The tests below test that cos(BigInt) = cos(Scalar) which is DWIM, but not
@@ -46,10 +46,11 @@
 ok (exp($bi), exp(1));
 ok (atan2($bi,$bi), atan2(1,1));
 
-my $bf = Math::BigInt->new(1);
+my $bf = Math::BigInt->new(0);
 
-ok (cos($bf), cos(1));
-ok (sin($bf), sin(1));
-ok (exp($bf), exp(1));
-ok (atan2($bf,$bf), atan2(1,1));
+ok (cos($bf), cos(0));
+ok (sin($bf), sin(0));
+ok (exp($bf), exp(0));
+ok (atan2($bi,$bf), atan2(1,0));
+ok (atan2($bf,$bi), atan2(0,1));
 


##</code><code>##

$ perl -e'use bignum;print atan2(1,0), " ", atan2(0,1),$/'
1.5707963267949 0
$