As with pretty much every other thing involving the perl parser, the answer is a resounding yes

It seems that there are often limitations regarding the liberties that can be taken regarding overloading.
I have overloading subs (XSubs) that will overload '++' as: 
void overload_inc($V * object, SV * second, SV * switch) {
   /* code that adds 1 to the value held by object */ 
}

[download]
That always works perfectly well.
I've then considered that I should be able to do the same thing with the overloading of the '+=' operator: 
void overload_plus_eq(SV * object, SV * addon, SV * switch) {
   /*code that adds the value of addon to the value held by object */
}

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That attempt (in overload_plus_eq), to modify the object in place always fails when called by the '+=' operator - and I have never been able to write that XSub such that it is successfully called via overloading of '+=', unless it returns a new object that overwrites the existing one.
(Which, BTW, I think is what happens with the overloading of '+=' when only '+' is overloaded.)

I've assumed the incapacity of '+=' overloading to "modify in place" is related to '+=' NOT being seen as a "mutator" by overload.pm.
But maybe it's just that I haven't found the right way of doing it.

I've often wished that overloading of "log2" and "log10" was available ... but not to the extent that I'm going to commandeer a couple of these 'bitwise' operators for that purpose ;-)
(I doubt that could readily be achievable, anyway.)

I've noticed that overload.pm recognizes these additional bitwise operators as being valid, even though"feature 'bitwise'" has not been loaded: 
D:\>perl -Mwarnings -Moverload -e "use overload 'fu' => sub {return 1}
+;"
overload arg 'fu' is invalid at -e line 1.

D:\>perl -Mwarnings -Moverload -e "use overload '&.' => sub {return 1}
+;"

D:\>perl -Mwarnings -Moverload -e "use overload '&.=' => sub {return 1
+};"

D:\>

[download]
Seems a bit odd .... but perhaps of little or no importance.

Cheers,
Rob

In reply to Re^2: Puzzled by value of $overload::ops{binary} by syphilis
in thread Puzzled by value of $overload::ops{binary} by syphilis

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