As a one-liner

@a=map{m[(\d+)([a-z]?)-(\d+|[a-z])]and$2?(map{$1.$_}$2..$3):($1..$3)}s
+plit',',$s;
print "@a";
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Update: The above completely misses the 7!

Corrected and expanded for a little more clarity

print map{
    m[ (\d+) ([a-z]?) -? (\d+|[a-z])? ]x
    and $2
         ? ( map{ $1 . $_ } $2 .. $3 )
         : $3 ? ( $1 .. $3 )
              : ( $1 )
}split ',', $s;

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