s/^/#a) =>#(a) @\n    ~Z = (aZ)\n    (a1)_(a2) = (a1_a2)\n/
:
s/\(#*\)a\(\w*\)/\1B\2,\U&/g
y/ABbcdefghijklmnopqrstuvwxy/bacdefghijklmnopqrstuvwxyz/
h
s/_/ `mappend` /g
s/#/ Monoid /g
s/ /instance (/
s/@/where/
s/.Z/mempty/gp
g
/z/d
t