16 lines
653 B
Common Lisp
16 lines
653 B
Common Lisp
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;; A list containing the values of single-letter Roman numerals.
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(setf *roman-number-list*
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'((I 1) (V 5) (X 10) (L 50) (C 100) (D 500) (M 1000)))
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;; Converts a single Roman numeral letter into its equivalent decimal value.
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(defun letter-to-decimal (letter)
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(car (cdr ((lambda (lst f)
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(cond ((null lst) ())
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((eq (car (car lst)) letter) (car lst))
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(t (funcall f (cdr lst) f))))
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*roman-number-list*
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(lambda (lst f)
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(cond ((null lst) ())
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((eq (car (car lst)) letter) (car lst))
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(t (funcall f (cdr lst) f))))))))
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