[Mimedefang] add_recipient and delete_recipient

[Kenneth Porter]

On 7/16/2016 6:45 PM, Dianne Skoll wrote:
> And in fact you do that in a number of places.  And actually, "=" is not
> a comparison operator.  It's an assignment operator.  You most likely
> need to review your entire filter to make sure you use "eq" for string
> comparisons and "==" for numeric comparisons, rather than "=".

I've learned to code equality comparisons with the constant value on the 
left to make it easier to catch an inadvertent use of = where I meant 
==.  I don't know how effective that is in Perl but it will throw a 
compile-time error in C/C++ if the left operand is non-modifiable.  So 
"2 == x" instead of "x == 2", for example.