Converting to racket and with contracts
original commit: 581458f0be2d6adf04933b00515643c6e383087a
This commit is contained in:
Jay McCarthy
parent
7e00a44f62
commit
e2aeb764f6
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@ -1,391 +1,355 @@
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#lang racket/base
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(require racket/promise
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racket/contract)
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(module date mzscheme
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(provide/contract
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[date->string ((date?) (boolean?) . ->* . string?)]
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[date-display-format (parameter/c (symbols 'american 'chinese 'german 'indian 'irish 'julian 'iso-8601 'rfc2822))]
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[find-seconds ((integer-in 0 61)
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(integer-in 0 59)
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(integer-in 0 23)
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(integer-in 1 31)
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(integer-in 1 12)
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exact-nonnegative-integer?
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. -> .
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exact-integer?)]
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[date->julian/scalinger (date? . -> . exact-integer?)]
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[julian/scalinger->string (exact-integer? . -> . string?)])
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(require "list.rkt")
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;; Support for Julian calendar added by Shriram;
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;; current version only works until 2099 CE Gregorian
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(provide date->string
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date-display-format
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find-seconds
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date->julian/scalinger
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julian/scalinger->string)
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(define date-display-format
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(make-parameter 'american))
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(define month/number->string
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(lambda (x)
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(case x
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[(12) "December"] [(1) "January"] [(2) "February"]
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[(3) "March"] [(4) "April"] [(5) "May"]
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[(6) "June"] [(7) "July"] [(8) "August"]
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[(9) "September"] [(10) "October"] [(11) "November"]
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[else ""])))
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(define day/number->string
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(lambda (x)
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(case x
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[(0) "Sunday"]
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[(1) "Monday"]
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[(2) "Tuesday"]
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[(3) "Wednesday"]
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[(4) "Thursday"]
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[(5) "Friday"]
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[(6) "Saturday"]
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[else ""])))
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(define date->string
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(case-lambda
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[(date) (date->string date #f)]
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[(date time?)
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(let* ((add-zero (lambda (n) (if (< n 10)
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(string-append "0" (number->string n))
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(number->string n))))
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(year (number->string (date-year date)))
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(num-month (number->string (date-month date)))
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(week-day (day/number->string (date-week-day date)))
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(week-day-num (date-week-day date))
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(month (month/number->string (date-month date)))
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(day (number->string (date-day date)))
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(day-th (if (<= 11 (date-day date) 13)
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"th"
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(case (modulo (date-day date) 10)
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[(1) "st"]
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[(2) "nd"]
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[(3) "rd"]
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[(0 4 5 6 7 8 9) "th"])))
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(hour (date-hour date))
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(am-pm (if (>= hour 12) "pm" "am"))
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(hour24 (add-zero hour))
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(hour12 (number->string
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(cond
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[(zero? hour) 12]
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[(> hour 12) (- hour 12)]
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[else hour])))
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(minute (add-zero (date-minute date)))
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(second (add-zero (date-second date))))
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(let-values
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([(day time)
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(case (date-display-format)
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[(american)
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(values (list week-day ", " month " " day day-th ", " year)
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(list " " hour12 ":" minute ":" second am-pm))]
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[(chinese)
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(values
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(list year "/" num-month "/" day
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" \u661F\u671F" (case (date-week-day date)
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[(0) "\u5929"]
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[(1) "\u4E00"]
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[(2) "\u4E8C"]
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[(3) "\u4e09"]
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[(4) "\u56DB"]
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[(5) "\u4E94"]
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[(6) "\u516D"]
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[else ""]))
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(list " " hour24 ":" minute ":" second))]
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[(indian)
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(values (list day "-" num-month "-" year)
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(list " " hour12 ":" minute ":" second am-pm))]
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[(german)
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(values (list day ". "
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(case (date-month date)
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[(1) "Januar"]
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[(2) "Februar"]
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[(3) "M\344rz"]
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[(4) "April"]
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[(5) "Mai"]
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[(6) "Juni"]
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[(7) "Juli"]
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[(8) "August"]
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[(9) "September"]
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[(10) "Oktober"]
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[(11) "November"]
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[(12) "Dezember"]
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[else ""])
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" " year)
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(list ", " hour24 "." minute))]
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[(irish)
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(values (list week-day ", " day day-th " " month " " year)
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(list ", " hour12 ":" minute am-pm))]
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[(julian)
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(values (list (julian/scalinger->string
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(date->julian/scalinger date)))
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(list ", " hour24 ":" minute ":" second))]
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[(iso-8601)
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(values
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(list year "-" (add-zero (date-month date)) "-" (add-zero (date-day date)))
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(list " " hour24 ":" minute ":" second))]
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[(rfc2822)
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(values
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(list (substring week-day 0 3) ", " day " " (substring month 0 3) " " year)
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(list* " " hour24 ":" minute ":" second " "
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(let* ([delta (date-time-zone-offset date)]
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[hours (quotient delta 3600)]
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[minutes (modulo (quotient delta 60) 60)])
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(list
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(if (negative? delta) "-" "+")
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(add-zero (abs hours))
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(add-zero minutes)))))]
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[else (error 'date->string "unknown date-display-format: ~s"
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(date-display-format))])])
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(apply string-append (if time?
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(append day time)
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day))))]))
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(define leap-year?
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(lambda (year)
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(or (= 0 (modulo year 400))
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(and (= 0 (modulo year 4))
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(not (= 0 (modulo year 100)))))))
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;; it's not clear what months mean in this context -- use days
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(define-struct date-offset (second minute hour day year))
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(define date-
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(lambda (date1 date2)
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(let* ((second (- (date-second date1) (date-second date2)))
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(minute (+ (- (date-minute date1) (date-minute date2))
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(if (< second 0) -1 0)))
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(hour (+ (- (date-hour date1) (date-hour date2))
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(if (< minute 0) -1 0)
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(cond [(equal? (date-dst? date1) (date-dst? date2)) 0]
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[(date-dst? date1) -1]
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[(date-dst? date2) 1])))
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(day (+ (- (date-year-day date1) (date-year-day date2))
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(if (< hour 0) -1 0)))
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(year (+ (- (date-year date1) (date-year date2))
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(if (< day 0) -1 0)))
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(fixup (lambda (s x) (if (< s 0) (+ s x) s))))
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(make-date-offset (fixup second 60)
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(fixup minute 60)
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(fixup hour 24)
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(fixup day (if (leap-year? (date-year date1)) 366 365))
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year))))
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;; Support for Julian calendar added by Shriram;
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;; current version only works until 2099 CE Gregorian
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#|
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(define-primitive seconds->date (num -> structure:date))
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(define-primitive current-seconds (-> num))
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(define-primitive date-second (structure:date -> num))
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(define-primitive date-minute (structure:date -> num))
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(define-primitive date-hour (structure:date -> num))
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(define-primitive date-day (structure:date -> num))
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(define-primitive date-month (structure:date -> num))
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(define-primitive date-year (structure:date -> num))
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(define-primitive date-week-day (structure:date -> num))
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(define-primitive date-year-day (structure:date -> num))
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(define-primitive date-dst? (structure:date -> bool))
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(define-primitive make-date (num num num num num num num num bool ->
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structure:date))
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(define-primitive expr->string (a -> string))
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(define-primitive foldl (case->
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((a z -> z) z (listof a) -> z)
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((a b z -> z) z (listof a) (listof b) -> z)
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((a b c z -> z) z (listof a) (listof b) (listof c) -> z)
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(((arglistof x) ->* z) z (listof (arglistof x)) ->* z)))
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(define-primitive foldr (case->
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((a z -> z) z (listof a) -> z)
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((a b z -> z) z (listof a) (listof b) -> z)
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((a b c z -> z) z (listof a) (listof b) (listof c) -> z)
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(((arglistof x) ->* z) z (listof (arglistof x)) ->* z)))
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|#
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(define legal-formats
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(list 'american 'chinese 'german 'indian 'irish 'julian 'iso-8601 'rfc2822))
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(define date-display-format
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(make-parameter 'american
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(lambda (s)
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(unless (memq s legal-formats)
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(raise-type-error 'date-display-format
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(format "symbol in ~a" legal-formats)
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s))
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s)))
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(define month/number->string
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(lambda (x)
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(case x
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[(12) "December"] [(1) "January"] [(2) "February"]
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[(3) "March"] [(4) "April"] [(5) "May"]
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[(6) "June"] [(7) "July"] [(8) "August"]
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[(9) "September"] [(10) "October"] [(11) "November"]
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[else ""])))
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(define day/number->string
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(lambda (x)
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(case x
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[(0) "Sunday"]
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[(1) "Monday"]
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[(2) "Tuesday"]
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[(3) "Wednesday"]
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[(4) "Thursday"]
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[(5) "Friday"]
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[(6) "Saturday"]
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[else ""])))
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(define date->string
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(define date-offset->string
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(let ((first car)
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(second cadr))
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(case-lambda
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[(date) (date->string date #f)]
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[(date time?)
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(let* ((add-zero (lambda (n) (if (< n 10)
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(string-append "0" (number->string n))
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(number->string n))))
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(year (number->string (date-year date)))
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(num-month (number->string (date-month date)))
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(week-day (day/number->string (date-week-day date)))
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(week-day-num (date-week-day date))
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(month (month/number->string (date-month date)))
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(day (number->string (date-day date)))
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(day-th (if (<= 11 (date-day date) 13)
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"th"
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(case (modulo (date-day date) 10)
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[(1) "st"]
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[(2) "nd"]
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[(3) "rd"]
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[(0 4 5 6 7 8 9) "th"])))
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(hour (date-hour date))
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(am-pm (if (>= hour 12) "pm" "am"))
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(hour24 (add-zero hour))
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(hour12 (number->string
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(cond
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[(zero? hour) 12]
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[(> hour 12) (- hour 12)]
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[else hour])))
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(minute (add-zero (date-minute date)))
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(second (add-zero (date-second date))))
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(let-values
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([(day time)
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(case (date-display-format)
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[(american)
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(values (list week-day ", " month " " day day-th ", " year)
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(list " " hour12 ":" minute ":" second am-pm))]
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[(chinese)
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(values
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(list year "/" num-month "/" day
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" \u661F\u671F" (case (date-week-day date)
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[(0) "\u5929"]
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[(1) "\u4E00"]
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[(2) "\u4E8C"]
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[(3) "\u4e09"]
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[(4) "\u56DB"]
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[(5) "\u4E94"]
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[(6) "\u516D"]
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[else ""]))
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(list " " hour24 ":" minute ":" second))]
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[(indian)
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(values (list day "-" num-month "-" year)
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(list " " hour12 ":" minute ":" second am-pm))]
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[(german)
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(values (list day ". "
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(case (date-month date)
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[(1) "Januar"]
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[(2) "Februar"]
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[(3) "M\344rz"]
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[(4) "April"]
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[(5) "Mai"]
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[(6) "Juni"]
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[(7) "Juli"]
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[(8) "August"]
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[(9) "September"]
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[(10) "Oktober"]
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[(11) "November"]
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[(12) "Dezember"]
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[else ""])
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" " year)
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(list ", " hour24 "." minute))]
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[(irish)
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(values (list week-day ", " day day-th " " month " " year)
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(list ", " hour12 ":" minute am-pm))]
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[(julian)
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(values (list (julian/scalinger->string
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(date->julian/scalinger date)))
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(list ", " hour24 ":" minute ":" second))]
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[(iso-8601)
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(values
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(list year "-" (add-zero (date-month date)) "-" (add-zero (date-day date)))
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(list " " hour24 ":" minute ":" second))]
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[(rfc2822)
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(values
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(list (substring week-day 0 3) ", " day " " (substring month 0 3) " " year)
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(list* " " hour24 ":" minute ":" second " "
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(let* ([delta (date-time-zone-offset date)]
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[hours (quotient delta 3600)]
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[minutes (modulo (quotient delta 60) 60)])
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(list
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(if (negative? delta) "-" "+")
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(add-zero (abs hours))
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(add-zero minutes)))))]
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[else (error 'date->string "unknown date-display-format: ~s"
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(date-display-format))])])
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(apply string-append (if time?
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(append day time)
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day))))]))
|
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|
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(define leap-year?
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(lambda (year)
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(or (= 0 (modulo year 400))
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(and (= 0 (modulo year 4))
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(not (= 0 (modulo year 100)))))))
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[(date) (date-offset->string date #f)]
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[(date seconds?)
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(let* ((fields (list (list (date-offset-year date) "year")
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(list (date-offset-day date) "day")
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(list (date-offset-hour date) "hour")
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(list (date-offset-minute date) "minute")
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(list (if seconds? (date-offset-second date) 0) "second")))
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(non-zero-fields (foldl (lambda (x l)
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(if (= 0 (first x))
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l
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(cons x l)))
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null
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fields))
|
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(one-entry (lambda (b)
|
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(string-append
|
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(number->string (first b))
|
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" "
|
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(second b)
|
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(if (= 1 (first b)) "" "s")))))
|
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(cond
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[(null? non-zero-fields) ""]
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[(null? (cdr non-zero-fields)) (one-entry (car non-zero-fields))]
|
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[else (foldl (lambda (b string)
|
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(cond
|
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[(= 0 (first b)) string]
|
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[(string=? string "")
|
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(string-append "and "
|
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(one-entry b)
|
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string)]
|
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[else (string-append (one-entry b) ", " string)]))
|
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""
|
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non-zero-fields)]))])))
|
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|
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;; it's not clear what months mean in this context -- use days
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(define-struct date-offset (second minute hour day year))
|
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(define days-per-month
|
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(lambda (year month)
|
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(cond
|
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[(and (= month 2) (leap-year? year)) 29]
|
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[(= month 2) 28]
|
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[(<= month 7) (+ 30 (modulo month 2))]
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[else (+ 30 (- 1 (modulo month 2)))])))
|
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|
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(define date-
|
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(lambda (date1 date2)
|
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(let* ((second (- (date-second date1) (date-second date2)))
|
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(minute (+ (- (date-minute date1) (date-minute date2))
|
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(if (< second 0) -1 0)))
|
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(hour (+ (- (date-hour date1) (date-hour date2))
|
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(if (< minute 0) -1 0)
|
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(cond [(equal? (date-dst? date1) (date-dst? date2)) 0]
|
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[(date-dst? date1) -1]
|
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[(date-dst? date2) 1])))
|
||||
(day (+ (- (date-year-day date1) (date-year-day date2))
|
||||
(if (< hour 0) -1 0)))
|
||||
(year (+ (- (date-year date1) (date-year date2))
|
||||
(if (< day 0) -1 0)))
|
||||
(fixup (lambda (s x) (if (< s 0) (+ s x) s))))
|
||||
(make-date-offset (fixup second 60)
|
||||
(fixup minute 60)
|
||||
(fixup hour 24)
|
||||
(fixup day (if (leap-year? (date-year date1)) 366 365))
|
||||
year))))
|
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(define find-extreme-date-seconds
|
||||
(lambda (start offset)
|
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(let/ec found
|
||||
(letrec ([find-between
|
||||
(lambda (lo hi)
|
||||
(let ([mid (floor (/ (+ lo hi) 2))])
|
||||
(if (or (and (positive? offset) (= lo mid))
|
||||
(and (negative? offset) (= hi mid)))
|
||||
(found lo)
|
||||
(let ([mid-ok?
|
||||
(with-handlers ([exn:fail? (lambda (exn) #f)])
|
||||
(seconds->date mid)
|
||||
#t)])
|
||||
(if mid-ok?
|
||||
(find-between mid hi)
|
||||
(find-between lo mid))))))])
|
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(let loop ([lo start][offset offset])
|
||||
(let ([hi (+ lo offset)])
|
||||
(with-handlers ([exn:fail?
|
||||
(lambda (exn)
|
||||
; failed - must be between lo & hi
|
||||
(find-between lo hi))])
|
||||
(seconds->date hi))
|
||||
; succeeded; double offset again
|
||||
(loop hi (* 2 offset))))))))
|
||||
|
||||
(define get-min-seconds
|
||||
(let ([d (delay (find-extreme-date-seconds (current-seconds) -1))])
|
||||
(lambda ()
|
||||
(force d))))
|
||||
(define get-max-seconds
|
||||
(let ([d (delay (find-extreme-date-seconds (current-seconds) 1))])
|
||||
(lambda ()
|
||||
(force d))))
|
||||
|
||||
(define date-offset->string
|
||||
(let ((first car)
|
||||
(second cadr))
|
||||
(case-lambda
|
||||
[(date) (date-offset->string date #f)]
|
||||
[(date seconds?)
|
||||
(let* ((fields (list (list (date-offset-year date) "year")
|
||||
(list (date-offset-day date) "day")
|
||||
(list (date-offset-hour date) "hour")
|
||||
(list (date-offset-minute date) "minute")
|
||||
(list (if seconds? (date-offset-second date) 0) "second")))
|
||||
(non-zero-fields (foldl (lambda (x l)
|
||||
(if (= 0 (first x))
|
||||
l
|
||||
(cons x l)))
|
||||
null
|
||||
fields))
|
||||
(one-entry (lambda (b)
|
||||
(string-append
|
||||
(number->string (first b))
|
||||
" "
|
||||
(second b)
|
||||
(if (= 1 (first b)) "" "s")))))
|
||||
(cond
|
||||
[(null? non-zero-fields) ""]
|
||||
[(null? (cdr non-zero-fields)) (one-entry (car non-zero-fields))]
|
||||
[else (foldl (lambda (b string)
|
||||
(cond
|
||||
[(= 0 (first b)) string]
|
||||
[(string=? string "")
|
||||
(string-append "and "
|
||||
(one-entry b)
|
||||
string)]
|
||||
[else (string-append (one-entry b) ", " string)]))
|
||||
""
|
||||
non-zero-fields)]))])))
|
||||
(define find-seconds
|
||||
(lambda (sec min hour day month year)
|
||||
(let ([signal-error
|
||||
(lambda (msg)
|
||||
(error 'find-secs (string-append
|
||||
msg
|
||||
" (inputs: ~a ~a ~a ~a ~a ~a)")
|
||||
sec min hour day month year))])
|
||||
(let loop ([below-secs (get-min-seconds)]
|
||||
[secs (floor (/ (+ (get-min-seconds) (get-max-seconds)) 2))]
|
||||
[above-secs (get-max-seconds)])
|
||||
(let* ([date (seconds->date secs)]
|
||||
[compare
|
||||
(let loop ([inputs (list year month day
|
||||
hour min sec)]
|
||||
[tests (list (date-year date)
|
||||
(date-month date)
|
||||
(date-day date)
|
||||
(date-hour date)
|
||||
(date-minute date)
|
||||
(date-second date))])
|
||||
(cond
|
||||
[(null? inputs) 'equal]
|
||||
[else (let ([input (car inputs)]
|
||||
[test (car tests)])
|
||||
(if (= input test)
|
||||
(loop (cdr inputs) (cdr tests))
|
||||
(if (<= input test)
|
||||
'input-smaller
|
||||
'test-smaller)))]))])
|
||||
; (printf "~a ~a ~a~n" compare secs (date->string date))
|
||||
(cond
|
||||
[(eq? compare 'equal) secs]
|
||||
[(or (= secs below-secs) (= secs above-secs))
|
||||
(signal-error "non-existent date")]
|
||||
[(eq? compare 'input-smaller)
|
||||
(loop below-secs (floor (/ (+ secs below-secs) 2)) secs)]
|
||||
[(eq? compare 'test-smaller)
|
||||
(loop secs (floor (/ (+ above-secs secs) 2)) above-secs)]))))))
|
||||
|
||||
(define days-per-month
|
||||
(lambda (year month)
|
||||
(cond
|
||||
[(and (= month 2) (leap-year? year)) 29]
|
||||
[(= month 2) 28]
|
||||
[(<= month 7) (+ 30 (modulo month 2))]
|
||||
[else (+ 30 (- 1 (modulo month 2)))])))
|
||||
;; date->julian/scalinger :
|
||||
;; date -> number [julian-day]
|
||||
|
||||
(define find-extreme-date-seconds
|
||||
(lambda (start offset)
|
||||
(let/ec found
|
||||
(letrec ([find-between
|
||||
(lambda (lo hi)
|
||||
(let ([mid (floor (/ (+ lo hi) 2))])
|
||||
(if (or (and (positive? offset) (= lo mid))
|
||||
(and (negative? offset) (= hi mid)))
|
||||
(found lo)
|
||||
(let ([mid-ok?
|
||||
(with-handlers ([exn:fail? (lambda (exn) #f)])
|
||||
(seconds->date mid)
|
||||
#t)])
|
||||
(if mid-ok?
|
||||
(find-between mid hi)
|
||||
(find-between lo mid))))))])
|
||||
(let loop ([lo start][offset offset])
|
||||
(let ([hi (+ lo offset)])
|
||||
(with-handlers ([exn:fail?
|
||||
(lambda (exn)
|
||||
; failed - must be between lo & hi
|
||||
(find-between lo hi))])
|
||||
(seconds->date hi))
|
||||
; succeeded; double offset again
|
||||
(loop hi (* 2 offset))))))))
|
||||
;; Note: This code is correct until 2099 CE Gregorian
|
||||
|
||||
(define get-min-seconds
|
||||
(let ([d (delay (find-extreme-date-seconds (current-seconds) -1))])
|
||||
(lambda ()
|
||||
(force d))))
|
||||
(define get-max-seconds
|
||||
(let ([d (delay (find-extreme-date-seconds (current-seconds) 1))])
|
||||
(lambda ()
|
||||
(force d))))
|
||||
(define (date->julian/scalinger date)
|
||||
(let ((day (date-day date))
|
||||
(month (date-month date))
|
||||
(year (date-year date)))
|
||||
(let ((year (+ 4712 year)))
|
||||
(let ((year (if (< month 3) (sub1 year) year)))
|
||||
(let ((cycle-number (quotient year 4))
|
||||
(cycle-position (remainder year 4)))
|
||||
(let ((base-day (+ (* 1461 cycle-number) (* 365 cycle-position))))
|
||||
(let ((month-day-number (case month
|
||||
((3) 0)
|
||||
((4) 31)
|
||||
((5) 61)
|
||||
((6) 92)
|
||||
((7) 122)
|
||||
((8) 153)
|
||||
((9) 184)
|
||||
((10) 214)
|
||||
((11) 245)
|
||||
((12) 275)
|
||||
((1) 306)
|
||||
((2) 337))))
|
||||
(let ((total-days (+ base-day month-day-number day)))
|
||||
(let ((total-days/march-adjustment (+ total-days 59)))
|
||||
(let ((gregorian-adjustment (cond
|
||||
((< year 1700) 11)
|
||||
((< year 1800) 12)
|
||||
(else 13))))
|
||||
(let ((final-date (- total-days/march-adjustment
|
||||
gregorian-adjustment)))
|
||||
final-date)))))))))))
|
||||
|
||||
(define find-seconds
|
||||
(lambda (sec min hour day month year)
|
||||
(let ([signal-error
|
||||
(lambda (msg)
|
||||
(error 'find-secs (string-append
|
||||
msg
|
||||
" (inputs: ~a ~a ~a ~a ~a ~a)")
|
||||
sec min hour day month year))])
|
||||
(let loop ([below-secs (get-min-seconds)]
|
||||
[secs (floor (/ (+ (get-min-seconds) (get-max-seconds)) 2))]
|
||||
[above-secs (get-max-seconds)])
|
||||
(let* ([date (seconds->date secs)]
|
||||
[compare
|
||||
(let loop ([inputs (list year month day
|
||||
hour min sec)]
|
||||
[tests (list (date-year date)
|
||||
(date-month date)
|
||||
(date-day date)
|
||||
(date-hour date)
|
||||
(date-minute date)
|
||||
(date-second date))])
|
||||
(cond
|
||||
[(null? inputs) 'equal]
|
||||
[else (let ([input (car inputs)]
|
||||
[test (car tests)])
|
||||
(if (= input test)
|
||||
(loop (cdr inputs) (cdr tests))
|
||||
(if (<= input test)
|
||||
'input-smaller
|
||||
'test-smaller)))]))])
|
||||
; (printf "~a ~a ~a~n" compare secs (date->string date))
|
||||
(cond
|
||||
[(eq? compare 'equal) secs]
|
||||
[(or (= secs below-secs) (= secs above-secs))
|
||||
(signal-error "non-existent date")]
|
||||
[(eq? compare 'input-smaller)
|
||||
(loop below-secs (floor (/ (+ secs below-secs) 2)) secs)]
|
||||
[(eq? compare 'test-smaller)
|
||||
(loop secs (floor (/ (+ above-secs secs) 2)) above-secs)]))))))
|
||||
|
||||
;; date->julian/scalinger :
|
||||
;; date -> number [julian-day]
|
||||
|
||||
;; Note: This code is correct until 2099 CE Gregorian
|
||||
|
||||
(define (date->julian/scalinger date)
|
||||
(let ((day (date-day date))
|
||||
(month (date-month date))
|
||||
(year (date-year date)))
|
||||
(let ((year (+ 4712 year)))
|
||||
(let ((year (if (< month 3) (sub1 year) year)))
|
||||
(let ((cycle-number (quotient year 4))
|
||||
(cycle-position (remainder year 4)))
|
||||
(let ((base-day (+ (* 1461 cycle-number) (* 365 cycle-position))))
|
||||
(let ((month-day-number (case month
|
||||
((3) 0)
|
||||
((4) 31)
|
||||
((5) 61)
|
||||
((6) 92)
|
||||
((7) 122)
|
||||
((8) 153)
|
||||
((9) 184)
|
||||
((10) 214)
|
||||
((11) 245)
|
||||
((12) 275)
|
||||
((1) 306)
|
||||
((2) 337))))
|
||||
(let ((total-days (+ base-day month-day-number day)))
|
||||
(let ((total-days/march-adjustment (+ total-days 59)))
|
||||
(let ((gregorian-adjustment (cond
|
||||
((< year 1700) 11)
|
||||
((< year 1800) 12)
|
||||
(else 13))))
|
||||
(let ((final-date (- total-days/march-adjustment
|
||||
gregorian-adjustment)))
|
||||
final-date)))))))))))
|
||||
|
||||
;; julian/scalinger->string :
|
||||
;; number [julian-day] -> string [julian-day-format]
|
||||
|
||||
(define (julian/scalinger->string julian-day)
|
||||
(apply string-append
|
||||
(cons "JD "
|
||||
(reverse
|
||||
(let loop ((reversed-digits (map number->string
|
||||
(let loop ((jd julian-day))
|
||||
(if (zero? jd) null
|
||||
(cons (remainder jd 10)
|
||||
(loop (quotient jd 10))))))))
|
||||
(cond
|
||||
((or (null? reversed-digits)
|
||||
(null? (cdr reversed-digits))
|
||||
(null? (cdr (cdr reversed-digits)))
|
||||
(null? (cdr (cdr (cdr reversed-digits)))))
|
||||
(list (apply string-append (reverse reversed-digits))))
|
||||
(else (cons (apply string-append
|
||||
(list " "
|
||||
(caddr reversed-digits)
|
||||
(cadr reversed-digits)
|
||||
(car reversed-digits)))
|
||||
(loop (cdr (cdr (cdr reversed-digits))))))))))))
|
||||
|
||||
)
|
||||
;; julian/scalinger->string :
|
||||
;; number [julian-day] -> string [julian-day-format]
|
||||
|
||||
(define (julian/scalinger->string julian-day)
|
||||
(apply string-append
|
||||
(cons "JD "
|
||||
(reverse
|
||||
(let loop ((reversed-digits (map number->string
|
||||
(let loop ((jd julian-day))
|
||||
(if (zero? jd) null
|
||||
(cons (remainder jd 10)
|
||||
(loop (quotient jd 10))))))))
|
||||
(cond
|
||||
((or (null? reversed-digits)
|
||||
(null? (cdr reversed-digits))
|
||||
(null? (cdr (cdr reversed-digits)))
|
||||
(null? (cdr (cdr (cdr reversed-digits)))))
|
||||
(list (apply string-append (reverse reversed-digits))))
|
||||
(else (cons (apply string-append
|
||||
(list " "
|
||||
(caddr reversed-digits)
|
||||
(cadr reversed-digits)
|
||||
(car reversed-digits)))
|
||||
(loop (cdr (cdr (cdr reversed-digits))))))))))))
|
||||
Loading…
Reference in New Issue
Block a user