Hello, I am attempting to make a binary to hexadecimal number converter--however the catch is that I want it to convert an arbirtrarily long string of 0s and 1s. I'm using the fact that grouping the 0s and 1s into pairs of 4s will allow for quick and easy conversion, however I'm getting some errors. (p.s., I should probably should say that this is a golf attempt, to explain myself(you'll see)). The code's here, though I break it up to attempt to explain my logic: 
$_="10101010000011110101000101001110110010100111";

(reverse, #I need it reversed so what follows will work
s/(.)(.)(.)(.)/ #get the four digits && store them
$a+=2**($_-1)if$$_/ee #take two to the $_power if
                      #$$_ exists(e.g., $1 set, $2 set,etc)
for 1..4 &&           #do it for each digit and
s/1(?=\d)// && y/0-5/a-f/)  #if 2-digit answer convert
                            #to appropriate letter for hex
for split /(....)/;         #do this for all 4 digits
                            #in $_
print $a, "\n";

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Here's the code, minus the comments, so it appears somewhat(hopefully) clearer now that you understand what I'm trying to do. 
$_="10101010000011110101000101001110110010100111";
(reverse,s/(.)(.)(.)(.)/$a+=2**($_-1)if$$_/ee for 1..4 &&
         s/1(?=\d)// && y/0-5/a-f/)  for split /(....)/;
print $a, "\n";

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using g++, here's the error I get:
|syntax error at bin2hex.pl line 3, near "s/(.)(.)(.)(.)/$a+=2**($_-1)if$$_/ee for "
Execution of bin2hex.pl aborted due to compilation errors.|

In reply to bin2hex converter by Anonymous Monk

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