what I really want is some way of addressing all the characters in a string/number, apply some function to it that returns a number, then add those numbers up. 

$_=6491;
sum(some_function(split//));

[download]
Use your favourite sum(), and your favorite some_function() ;)

These things are very hard, and I think completely impossible with regexes.
Although... 
s/(\d)/$s+=$1/ge; # $s is the sum...

# Which leaves garbage in $_, but is a single stroke shorter than:

$s+=$_ for split//;

# But thenagain, this is even shorter:

$s+=$_ for/./g;

[download]

U28geW91IGNhbiBhbGwgcm90MTMgY
W5kIHBhY2soKS4gQnV0IGRvIHlvdS
ByZWNvZ25pc2UgQmFzZTY0IHdoZW4
geW91IHNlZSBpdD8gIC0tIEp1ZXJk

In reply to Re: Re: Re: Requiring backtracking a certain number of times by Juerd
in thread Requiring backtracking a certain number of times by dragonchild

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