v='Twelve drummers drumm0Eleven pipers pip0Ten lords a-leap0Nine ladies danc0Eight maids a-milk0Seven swans a-swimm0Six geese a-lay0Five golden rings0Four calling birds0Three French hens0Two turtle doves0twelf0eleven0ten0nin0eigh0seven0six0fif0four0third0second0first'.split('0')
p=0.&println
for(i=12;j=i--;p("A${i-11?'nd a':''} partridge in a pear tree${i?'.':'!'}\n"))for(p("On the ${v[i+11]+(i<9?'th':'')} day of Christmas,\nmy true love sent to me");j<12;)p(v[j++-1]+(j<9?'ing,':','))
Note that non-ascii characters in the above source code will be escaped (such as \x9f).