The Twelve Days of Christmas: Difference between revisions
→{{header|Scheme}}: Add implementation
(→{{header|Common Lisp}}: Simplify) |
(→{{header|Scheme}}: Add implementation) |
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Three French hens,
Two turtle doves and
A partridge in a pear tree.</pre>
=={{header|Scheme}}==
Without Common Lisp's <tt>format</tt>, we sadly have to hard-code the list of ordinals.
<lang scheme>(define take (lambda [n lst] ; return the first n items of a list
(if (or (null? lst) (<= n 0))
'()
(cons (car lst) (take (- n 1) (cdr lst))))))
(let
((days '("first" "second" "third" "fourth" "fifth" "sixth" "seventh" "eighth" "ninth" "tenth" "eleventh" "twelfth"))
(gifts '("A partridge in a pear tree." "Two turtle doves, and"
"Three French hens," "Four calling birds,"
"Five gold rings," "Six geese a-laying,"
"Seven swans a-swimming," "Eight maids a-milking,"
"Nine ladies dancing," "Ten lords a-leaping,"
"Eleven pipers piping," "Twelve drummers drumming," )))
(do ((left days (cdr left))
(day 1 (+ day 1)))
((null? left) #t)
(display "On the ")
(display (car left))
(display " day of Christmas, my true love sent to me:")
(newline)
(do ((daily (reverse (take day gifts)) (cdr daily)))
((null? daily) #t)
(display (car daily))
(newline))
(newline)))
(exit)</lang>
{{Out}}
<pre>On the first day of Christmas, my true love sent to me:
A partridge in a pear tree.
On the second day of Christmas, my true love sent to me:
Two turtle doves, and
A partridge in a pear tree.
[...]
On the twelfth day of Christmas, my true love sent to me:
Twelve drummers drumming,
Eleven pipers piping,
Ten lords a-leaping,
Nine ladies dancing,
Eight maids a-milking,
Seven swans a-swimming,
Six geese a-laying,
Five gold rings,
Four calling birds,
Three French hens,
Two turtle doves, and
A partridge in a pear tree.</pre>
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