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# French Republican calendar

French Republican calendar
You are encouraged to solve this task according to the task description, using any language you may know.

Write a program to convert dates between the Gregorian calendar and the French Republican calendar.

The year 1 of the Republican calendar began on 22 September 1792. There were twelve months (Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, and Fructidor) of 30 days each, followed by five intercalary days or Sansculottides (Fête de la vertu / Virtue Day, Fête du génie / Talent Day, Fête du travail / Labour Day, Fête de l'opinion / Opinion Day, and Fête des récompenses / Honours Day). In leap years (the years 3, 7, and 11) a sixth Sansculottide was added: Fête de la Révolution / Revolution Day.

As a minimum, your program should give correct results for dates in the range from 1 Vendémiaire 1 = 22 September 1792 to 10 Nivôse 14 = 31 December 1805 (the last day when the Republican calendar was officially in use). If you choose to accept later dates, be aware that there are several different methods (described on the Wikipedia page) about how to determine leap years after the year 14. You should indicate which method you are using. (Because of these different methods, correct programs may sometimes give different results for dates after 1805.)

Test your program by converting the following dates both from Gregorian to Republican and from Republican to Gregorian:

• 1 Vendémiaire 1 = 22 September 1792

• 1 Prairial 3 = 20 May 1795

• 27 Messidor 7 = 15 July 1799 (Rosetta Stone discovered)

• Fête de la Révolution 11 = 23 September 1803

• 10 Nivôse 14 = 31 December 1805

## BBC BASIC

Computes leap years using the "continuous" method: a year in the Republican calendar is a leap year if and only if the number of the following year is divisible by 4 but not by 100 unless also by 400. No attempt is made to deal with ill-formed or invalid input dates.

`REM >frrepcal:DIM gregorian\$(11)DIM gregorian%(11)DIM republican\$(11)DIM sansculottides\$(5)gregorian\$() = "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"gregorian%() = 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31REM 7-bit ASCII encoding, so no accents on French wordsrepublican\$() = "Vendemiaire", "Brumaire", "Frimaire", "Nivose", "Pluviose", "Ventose", "Germinal", "Floreal", "Prairial", "Messidor", "Thermidor", "Fructidor"sansculottides\$() = "Fete de la vertu", "Fete du genie", "Fete du travail", "Fete de l'opinion", "Fete des recompenses", "Fete de la Revolution":PRINT "*** French  Republican ***"PRINT "*** calendar converter ***"PRINT "Enter a date to convert, in the format 'day month year'"PRINT "e.g.: 1 Prairial 3,"PRINT "      20 May 1795."PRINT "For Sansculottides, use 'day year'"PRINT "e.g.: Fete de l'opinion 9."PRINT "Or just press 'RETURN' to exit the program."PRINTREPEAT  INPUT LINE "> " src\$  IF src\$ <> "" THEN    PROC_split(src\$, day%, month%, year%)    REM for simplicity, we assume that years up to 1791 are Republican    REM and years from 1792 onwards are Gregorian    IF year% < 1792 THEN      REM convert Republican date to number of days elapsed      REM since 21 September 1792, then convert that number      REM to the Gregorian date      PROC_day_to_gre(FN_rep_to_day(day%, month%, year%), day%, month%, year%)      PRINT; day%; " "; gregorian\$(month% - 1); " " year%    ELSE      REM convert Gregorian date to Republican, via      REM number of days elapsed since 21 September 1792      PROC_day_to_rep(FN_gre_to_day(day%, month%, year%), day%, month%, year%)      IF month% = 13 THEN        PRINT sansculottides\$(day% - 1); " "; year%      ELSE        PRINT; day%; " "; republican\$(month% - 1); " "; year%      ENDIF    ENDIF  ENDIFUNTIL src\$ = ""END:DEF PROC_split(s\$, RETURN d%, RETURN m%, RETURN y%)LOCAL month_and_year\$, month\$, months\$(), i%DIM months\$(11)IF LEFT\$(s\$, 4) = "Fete" THEN  m% = 13  FOR i% = 0 TO 5    IF LEFT\$(s\$, LEN sansculottides\$(i%)) = sansculottides\$(i%) THEN      d% = i% + 1      y% = VAL(RIGHT\$(s\$, LEN s\$ - LEN sansculottides\$(i%) - 1))    ENDIF  NEXTELSE  d% = VAL(LEFT\$(s\$, INSTR(s\$, " ") - 1))  month_and_year\$ = MID\$(s\$, INSTR(s\$, " ") + 1)  month\$ = LEFT\$(month_and_year\$, INSTR(month_and_year\$, " ") - 1)  y% = VAL(MID\$(month_and_year\$, INSTR(month_and_year\$, " ") + 1))  IF y% < 1792 THEN months\$() = republican\$() ELSE months\$() = gregorian\$()  FOR i% = 0 TO 11    IF months\$(i%) = month\$ THEN m% = i% + 1  NEXTENDIFENDPROC:DEF FN_gre_to_day(d%, m%, y%)REM modified & repurposed from code given atREM https://www.staff.science.uu.nl/~gent0113/calendar/isocalendar_text5.htmIF m% < 3 THEN  y% -= 1  m% += 12ENDIF= INT(365.25 * y%) - INT(y% / 100) + INT(y% / 400) + INT(30.6 * (m% + 1)) + d% - 654842:DEF FN_rep_to_day(d%, m%, y%)REM assume that a year is a leap year iff the _following_ year isREM divisible by 4, but not by 100 unless also by 400REMREM other methods for computing Republican leap years existIF m% = 13 THEN  m% -= 1  d% += 30ENDIFIF FN_rep_leap(y%) THEN d% -= 1= 365 * y% + INT((y% + 1) / 4) - INT((y% + 1) / 100) + INT((y% + 1) / 400) + 30 * m% + d% - 395:DEF PROC_day_to_gre(day%, RETURN d%, RETURN m%, RETURN y%)y% = INT(day% / 365.25)d% = day% - INT(365.25 * y%) + 21y% += 1792d% += INT(y% / 100) - INT(y% / 400) - 13m% = 8WHILE d% > gregorian%(m%)  d% -= gregorian%(m%)  m% += 1  IF m% = 12 THEN    m% = 0    y% += 1    IF FN_gre_leap(y%) THEN gregorian%(1) = 29 ELSE gregorian%(1) = 28  ENDIFENDWHILEm% += 1ENDPROC:DEF PROC_day_to_rep(day%, RETURN d%, RETURN m%, RETURN y%)LOCAL sansculottides%y% = INT(day% / 365.25)IF FN_rep_leap(y%) THEN y% -= 1d% = day% - INT(365.25 * y%) + INT((y% + 1) / 100) - INT((y% + 1) / 400)y% += 1m% = 1IF FN_rep_leap(y%) THEN sansculottides% = 6 ELSE sansculottides% = 5WHILE d% > 30  d% -= 30  m% += 1  IF m% = 13 THEN    IF d% > sansculottides% THEN      d% -= sansculottides%      m% = 1      y% += 1      IF FN_rep_leap(y%) THEN sansculottides% = 6 ELSE sansculottides% = 5    ENDIF  ENDIFENDWHILEENDPROC:DEF FN_rep_leap(year%)REM see comment at the beginning of FN_rep_to_day= ((year% + 1) MOD 4 = 0 AND ((year% + 1) MOD 100 <> 0 OR (year% + 1) MOD 400 = 0)):DEF FN_gre_leap(year%)= (year% MOD 4 = 0 AND (year% MOD 100 <> 0 OR year% MOD 400 = 0))`

Output for the test dates:

```*** French  Republican ***
*** calendar converter ***
Enter a date to convert, in the format 'day month year'
e.g.: 1 Prairial 3,
20 May 1795.
For Sansculottides, use 'day year'
e.g.: Fete de l'opinion 9.
Or just press 'RETURN' to exit the program.

> 1 Vendemiaire 1
22 September 1792
> 22 September 1792
1 Vendemiaire 1
> 1 Prairial 3
20 May 1795
> 20 May 1795
1 Prairial 3
> 27 Messidor 7
15 July 1799
> 15 July 1799
27 Messidor 7
> Fete de la Revolution 11
23 September 1803
> 23 September 1803
Fete de la Revolution 11
> 10 Nivose 14
31 December 1805
> 31 December 1805
10 Nivose 14```

Output for a few subsequent dates:

```> 18 March 1871
27 Ventose 79
> 25 August 1944
7 Fructidor 152
> 19 September 2016
Fete du travail 224```

## FreeBASIC

Translation of: BBC BASIC

Computes leap years using the "continuous" method: a year in the Republican calendar is a leap year if and only if the number of the following year is divisible by 4 but not by 100 unless also by 400. No attempt is made to deal with ill-formed or invalid input dates.

`' version 18 Pluviose 227' compile with: fbc -s console' retained the original comments for then BBC BASIC entry #Macro rep_leap (_year)    ' see comment at the beginning of rep_to_day    ((_year +1) Mod 4 = 0 And ((_year +1) Mod 100 <> 0 Or (_year +1) Mod 400 = 0))#EndMacro #Macro gre_leap (_year)    (_year Mod 4 = 0 And (_year Mod 100 <> 0 Or _year Mod 400 = 0))#EndMacro Dim Shared As UInteger gregorian(11) => {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}Dim Shared As String gregorian_s(11), republican(11), sanscolottides(5)' 7-bit ASCII encoding, so no accents on French wordsData "January", "February", "March", "April", "May", "June"Data "July", "August", "September", "October", "November", "December"Data "Vendemiaire", "Brumaire", "Frimaire","Nivose", "Pluviose", "Ventose"Data "Germinal", "Floreal", "Prairial", "Messidor", "Thermidor", "Fructidor"Data "Fete de la Vertu", "Fete du Genie", "Fete du Travail", "Fete de l'Opinion"Data "Fete des Recompenses","Fete de la Revolution"RestoreFor i As UInteger = 0 To 11    Read gregorian_s(i)NextFor i As UInteger = 0 To 11    Read republican(i)NextFor i As UInteger = 0 To 5    Read sanscolottides(i)Next Sub split(s As String, ByRef d As UInteger, ByRef m As UInteger, ByRef y As UInteger)     Dim As String month_and_year, Month    Dim As UInteger i     s = LCase(Trim(s)) : d = 0 : m = 0 : y = 0    If Left(s,4) = "fete" Then        m = 13        For i = 0 To 5            If Left(s, Len(sanscolottides(i))) = LCase(sanscolottides(i)) Then                d = i +1                y = Val(Right(s, Len(s) - Len(sanscolottides(i)) -1))            End If        Next    Else        d = Val(Left(s, InStr(s, " ") -1))        month_and_year = Mid(s, InStr(s, " ") +1)        Month = Left(month_and_year, InStr(month_and_year, " ") -1)        y = Val(Mid(month_and_year, InStr(month_and_year, " ") +1))        If y < 1792 Then            For i = 0 To 11                If LCase(republican(i)) = Month Then m = i +1            Next        Else            For i = 0 To 11                If LCase(gregorian_s(i)) = Month Then m = i +1            Next        End If    End If End Sub Sub day_to_gre(Day As UInteger, ByRef d As UInteger, ByRef m As UInteger, ByRef y As UInteger)     y = Fix(Day / 365.25)    d = Day - Fix(365.25 * y) + 21    y += 1792    d += y \ 100 - y \ 400 - 13    m = 8     While d > gregorian(m)        d -= gregorian(m)        m += 1        If m = 12 Then            m = 0            y += 1            If gre_leap(y) Then gregorian(1) = 29 Else gregorian(1) = 28        End If    Wend    gregorian(1) = 28    m += 1 End Sub Function gre_to_day(d As UInteger, m As UInteger, y As UInteger) As UInteger     ' modified & repurposed from code given at    ' https://www.staff.science.uu.nl/~gent0113/calendar/isocalendar_text5.htm     If m < 3 Then        y -= 1        m += 12    End If    Return Fix(365.25 * y) - y \ 100 + y \ 400 + Fix(30.6 * (m +1)) + d - 654842 End Function Function rep_to_day(d As UInteger, m As UInteger, y As UInteger) As UInteger     ' assume that a year is a leap year iff the _following_ year is    ' divisible by 4, but not by 100 unless also by 400    '    ' other methods for computing republican leap years exist     If m = 13 Then        m -= 1        d += 30    End If    If rep_leap(y) Then d -= 1     Return 365 * y + (y +1) \ 4 - (y +1) \ 100 + (y +1) \ 400 + 30 * m + d - 395 End Function Sub day_to_rep(Day As UInteger, ByRef d As UInteger, ByRef m As UInteger, ByRef y As UInteger)     Dim As UInteger sansculottides = 5     y = Fix(Day / 365.25)    If rep_leap(y) Then y -= 1    d = Day - Fix(365.25 * y) + (y +1) \ 100 - (y +1) \ 400    y += 1    m = 1    If rep_leap(y) Then sansculottides = 6    While d > 30        d -= 30        m += 1        If m = 13 Then            If d > sansculottides Then                d -= sansculottides                m = 1                y += 1                If rep_leap(y) Then sansculottides = 6 Else sansculottides = 5            End If        End If    Wend End Sub ' ------=< main >=------ Dim As UInteger Day, Month, YearDim As String src Print "*** French  Republican ***"Print "*** calendar converter ***"Print "Enter a date to convert, in the format 'day month year'"Print "e.g.: 1 Prairial 3,"Print "      20 May 1795."Print "For Sansculottides, use 'day year'"Print "e.g.: Fete de l'opinion 9."Print "Or just press 'RETURN' to exit the program."Print Do    Line Input "> ", src    If src <> "" Then        split(src, Day, Month, Year)        If Day = 0 Or Month = 0 Or Year <= 0 Then            Print "Error in input"            Continue Do        End If        ' for simplicity, we assume that years up to 1791 are republican        ' and years from 1792 onwards are gregorian        If Year < 1792 Then            ' convert republican date to number of days elapsed            ' since 21 september 1792, then convert that number            ' to the gregorian date            day_to_gre(rep_to_day(Day, Month, Year),Day, Month, Year)            Print; Day; " "; gregorian_s(Month -1); " "; Year        Else            ' convert gregorian date to republican, via            ' number of days elapsed since 21 september 1792            day_to_rep(gre_to_day(Day, Month, Year), Day, Month, Year)            If Month = 13 Then                Print sanscolottides(Day -1); " "; Year            Else                Print ; Day; " "; republican(Month -1); " "; Year            End If        End If    End IfLoop Until src = "" End`
Output:
```> 1 Vendemiaire 1                   > 22 September 1792          > 1 Vendemiaire 1          > 23 September 1806          > 1 Vendemiaire 15
22 September 1792                   1 Vendemiaire 1              22 September 1792          1 Vendemiaire 15             23 September 1806
> 22 September 1792                 > 22 September 1793          > 1 Vendemiaire 2          > 24 September 1807          > 1 Vendemiaire 16
1 Vendemiaire 1                     1 Vendemiaire 2              22 September 1793          1 Vendemiaire 16             24 September 1807
> 1 Prairial 3                      > 22 September 1794          > 1 Vendemiaire 3          > 23 September 1808          > 1 Vendemiaire 17
20 May 1795                         1 Vendemiaire 3              22 September 1794          1 Vendemiaire 17             23 September 1808
> 20 May 1795                       > 23 September 1795          > 1 Vendemiaire 4          > 23 September 1809          > 1 Vendemiaire 18
1 Prairial 3                        1 Vendemiaire 4              23 September 1795          1 Vendemiaire 18             23 September 1809
> 27 Messidor 7                     > 22 September 1796          > 1 Vendemiaire 5          > 23 September 1810          > 1 Vendemiaire 19
15 July 1799                        1 Vendemiaire 5              22 September 1796          1 Vendemiaire 19             23 September 1810
> 15 July 1799                      > 22 September 1797          > 1 Vendemiaire 6          > 24 September 1811          > 1 Vendemiaire 20
27 Messidor 7                       1 Vendemiaire 6              22 September 1797          1 Vendemiaire 20             24 September 1811
> Fete de la Revolution 11          > 22 September 1798          > 1 Vendemiaire 7          > 23 September 2015          > 1 Vendemiaire 224
23 September 1803                   1 Vendemiaire 7              22 September 1798          1 Vendemiaire 224            23 September 2015
> 23 September 1803                 > 23 September 1799          > 1 Vendemiaire 8          > 22 September 2016          > 1 Vendemiaire 225
Fete de la Revolution 11            1 Vendemiaire 8              23 September 1799          1 Vendemiaire 225            22 September 2016
> 10 Nivose 14                      > 23 September 1800          > 1 Vendemiaire 9          > 22 September 2017          > 1 Vendemiaire 226
31 December 1805                    1 Vendemiaire 9              23 September 1800          1 Vendemiaire 226            22 September 2017
> 31 December 1805                  > 23 September 1801          > 1 Vendemiaire 10         > 22 September 2018          > 1 Vendemiaire 227
10 Nivose 14                        1 Vendemiaire 10             23 September 1801          1 Vendemiaire 227            22 September 2018
> 23 September 1802          > 1 Vendemiaire 11         > 23 September 2019          > 1 Vendemiaire 228
1 Vendemiaire 11             23 September 1802          1 Vendemiaire 228            23 September 2019
> 24 September 1803          > 1 Vendemiaire 12         > 22 September 2020          > 1 Vendemiaire 229
1 Vendemiaire 12             24 September 1803          1 Vendemiaire 229            22 September 2020
> 23 September 1804          > 1 Vendemiaire 13
1 Vendemiaire 13             23 September 1804
> 23 September 1805          > 1 Vendemiaire 14
1 Vendemiaire 14             23 September 1805```

## F#

` // French Republican Calander: Nigel Galloway. April 16th., 2021let firstDay=System.DateTime.Parse("22/9/1792")type monthsFRC= Vendemiaire =   0               |Brumaire    =  30               |Frimaire    =  60               |Nivose      =  90               |Pluviose    = 120               |Ventose     = 150               |Germinal    = 180               |Floral      = 210               |Prairial    = 240               |Messidor    = 270               |Thermidor   = 300               |Fructidor   = 330               |Virtue      = 360               |Talent      = 361               |Labour      = 362               |Opinion     = 363               |Honours     = 364               |Revolution  = 365type months= January    =  1            |February   =  2            |March      =  3            |April      =  4            |May        =  5            |June       =  6            |July       =  7            |August     =  8             |September  =  9            |October    = 10            |November   = 11            |December   = 12let frc2Greg n (g:monthsFRC) l=firstDay+System.TimeSpan.FromDays(float((l-1)*365+l/4+(int g)+n-1))let rec fG n g=let i=match g with 3 |7 |11->366 |_->365 in if n<i then (n,g) else fG(n-i)(g+1)let Greg2FRC n=let n,g=fG((n-firstDay).Days) 1               match n/30,n%30 with (12,n)->(1,enum<monthsFRC>(360+n),g) |(n,l)->(l+1,enum<monthsFRC>(n*30),g)let n=(frc2Greg 1 monthsFRC.Vendemiaire 1) in printfn "%d %s %d -> %d %A %d" 1 "Vendemiaire" 1 n.Day (enum<months> n.Month) n.Year let n=(frc2Greg 27 monthsFRC.Messidor 7) in printfn "%d %s %d -> %d %A %d" 27 "Messidor" 7 n.Day (enum<months> n.Month) n.Year let n=(frc2Greg 1 monthsFRC.Revolution 11) in printfn "%d %s %d -> %d %A %d" 1 "Revolution" 11 n.Day (enum<months> n.Month) n.Year let n=(frc2Greg 10 monthsFRC.Nivose 14) in printfn "%d %s %d -> %d %A %d" 10 "Nivose" 14 n.Day (enum<months> n.Month) n.Year let n,g,l=Greg2FRC(System.DateTime(1792,9,22)) in printfn "%d %s %d -> %d %A %d" 22 "September" 1792 n g l let n,g,l=Greg2FRC(System.DateTime(1799,7,15)) in printfn "%d %s %d -> %d %A %d" 15 "July" 1799 n g l let n,g,l=Greg2FRC(System.DateTime(1803,9,23)) in printfn "%d %s %d -> %d %A %d" 23 "September" 1803 n g l let n,g,l=Greg2FRC(System.DateTime(1805,12,31)) in printfn "%d %s %d -> %d %A %d" 31 "December" 1805 n g l  `
Output:
```1 Vendemiaire 1 -> 22 September 1792
27 Messidor 7 -> 15 July 1799
1 Revolution 11 -> 23 September 1803
10 Nivose 14 -> 31 December 1805
22 September 1792 -> 1 Vendemiaire 1
15 July 1799 -> 27 Messidor 7
23 September 1803 -> 1 Revolution 11
31 December 1805 -> 10 Nivose 14
```

## Go

Translation of: BBC Basic

A rather literal port, just for reference. Far from idiomatic Go.

`package main import (    "bufio"    "fmt"    "os"    "strconv"    "strings") var (    gregorianStr = []string{"January", "February", "March",        "April", "May", "June",        "July", "August", "September",        "October", "November", "December"}    gregorian     = []int{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}    republicanStr = []string{"Vendemiaire", "Brumaire", "Frimaire",        "Nivose", "Pluviose", "Ventose",        "Germinal", "Floreal", "Prairial",        "Messidor", "Thermidor", "Fructidor"}    sansculottidesStr = []string{"Fete de la vertu", "Fete du genie",        "Fete du travail", "Fete de l'opinion",        "Fete des recompenses", "Fete de la Revolution"}) func main() {    fmt.Println("*** French  Republican ***")    fmt.Println("*** calendar converter ***")    fmt.Println("Enter a date to convert, in the format 'day month year'")    fmt.Println("e.g.: 1 Prairial 3,")    fmt.Println("      20 May 1795.")    fmt.Println("For Sansculottides, use 'day year'")    fmt.Println("e.g.: Fete de l'opinion 9.")    fmt.Println("Or just press 'RETURN' to exit the program.")    fmt.Println()    for sc := bufio.NewScanner(os.Stdin); ; {        fmt.Print("> ")        sc.Scan()        src := sc.Text()        if src == "" {            return        }        day, month, year := split(src)        if year < 1792 {            day, month, year = dayToGre(repToDay(day, month, year))            fmt.Println(day, gregorianStr[month-1], year)        } else {            day, month, year := dayToRep(greToDay(day, month, year))            if month == 13 {                fmt.Println(sansculottidesStr[day-1], year)            } else {                fmt.Println(day, republicanStr[month-1], year)            }        }    }} func split(s string) (d, m, y int) {    if strings.HasPrefix(s, "Fete") {        m = 13        for i, sc := range sansculottidesStr {            if strings.HasPrefix(s, sc) {                d = i + 1                y, _ = strconv.Atoi(s[len(sc)+1:])            }        }    } else {        d, _ = strconv.Atoi(s[:strings.Index(s, " ")])        my := s[strings.Index(s, " ")+1:]        mStr := my[:strings.Index(my, " ")]        y, _ = strconv.Atoi(my[strings.Index(my, " ")+1:])        months := gregorianStr        if y < 1792 {            months = republicanStr        }        for i, mn := range months {            if mn == mStr {                m = i + 1            }        }    }    return} func greToDay(d, m, y int) int {    if m < 3 {        y--        m += 12    }    return y*36525/100 - y/100 + y/400 + 306*(m+1)/10 + d - 654842} func repToDay(d, m, y int) int {    if m == 13 {        m--        d += 30    }    if repLeap(y) {        d--    }    return 365*y + (y+1)/4 - (y+1)/100 + (y+1)/400 + 30*m + d - 395} func dayToGre(day int) (d, m, y int) {    y = day * 100 / 36525    d = day - y*36525/100 + 21    y += 1792    d += y/100 - y/400 - 13    m = 8    for d > gregorian[m] {        d -= gregorian[m]        m++        if m == 12 {            m = 0            y++            if greLeap(y) {                gregorian[1] = 29            } else {                gregorian[1] = 28            }        }    }    m++    return} func dayToRep(day int) (d, m, y int) {    y = (day-1) * 100 / 36525    if repLeap(y) {        y--    }    d = day - (y+1)*36525/100 + 365 + (y+1)/100 - (y+1)/400    y++    m = 1    sansculottides := 5    if repLeap(y) {        sansculottides = 6    }    for d > 30 {        d -= 30        m += 1        if m == 13 {            if d > sansculottides {                d -= sansculottides                m = 1                y++                sansculottides = 5                if repLeap(y) {                    sansculottides = 6                }            }        }    }    return} func repLeap(year int) bool {    return (year+1)%4 == 0 && ((year+1)%100 != 0 || (year+1)%400 == 0)} func greLeap(year int) bool {    return year%4 == 0 && (year%100 != 0 || year%400 == 0)}`
Output:
```\$ go run frc.go
*** French  Republican ***
*** calendar converter ***
Enter a date to convert, in the format 'day month year'
e.g.: 1 Prairial 3,
20 May 1795.
For Sansculottides, use 'day year'
e.g.: Fete de l'opinion 9.
Or just press 'RETURN' to exit the program.

> 1 Vendemiaire 1
22 September 1792
> 22 September 1792
1 Vendemiaire 1
> 1 Prairial 3
20 May 1795
> 20 May 1795
1 Prairial 3
> 27 Messidor 7
15 July 1799
> 15 July 1799
27 Messidor 7
> Fete de la Revolution 11
23 September 1803
> 23 September 1803
Fete de la Revolution 11
> 10 Nivose 14
31 December 1805
> 31 December 1805
10 Nivose 14
>
\$
```

More idiomatic

A start anyway. Computations extracted to a package, a type defined for French Republican Dates, time package from standard library used. Ignores invalid input rather than panicking.

`package frc import (    "fmt"    "strconv"    "strings"    "time") type Date struct {    Year  int    Month int    Day   int} func (d Date) String() string {    if d.Month == 13 {        return fmt.Sprintf("%s %d", sansculotidesStr[d.Day-1], d.Year)    }    return fmt.Sprintf("%d %s %d", d.Day, republicanStr[d.Month-1], d.Year)} func Parse(s string) (dt Date, ok bool) {    f := strings.Fields(s)    var err error    switch {    case len(f) == 3:        if dt.Day, err = strconv.Atoi(f[0]); err != nil {            return        }        i := 0        for republicanStr[i] != f[1] {            i++            if i == len(republicanStr) {                return            }        }        dt.Month = i + 1        if dt.Year, err = strconv.Atoi(f[2]); err != nil {            return        }        ok = true        return    case len(f) > 3:        for i, sc := range sansculotidesStr {            if strings.HasPrefix(s, sc) {                dt.Month = 13                dt.Day = i + 1                dt.Year, err = strconv.Atoi(s[len(sc)+1:])                if err == nil {                    ok = true                }                return            }        }    }    return} func (dt Date) ToGregorian() (y int, m time.Month, d int) {    yr, mn, dy := dayToGre(repToDay(dt.Day, dt.Month, dt.Year))    return yr, time.Month(mn), dy} func FromGregorian(y int, m time.Month, d int) Date {    day, month, year := dayToRep(greToDay(d, int(m), y))    return Date{Year: year, Month: month, Day: day}}var (    gregorian     = []int{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}    republicanStr = []string{"Vendemiaire", "Brumaire", "Frimaire",        "Nivose", "Pluviose", "Ventose",        "Germinal", "Floreal", "Prairial",        "Messidor", "Thermidor", "Fructidor"}    sansculotidesStr = []string{"Fete de la vertu", "Fete du genie",        "Fete du travail", "Fete de l'opinion",        "Fete des recompenses", "Fete de la Revolution"}) func greToDay(d, m, y int) int {    if m < 3 {        y--        m += 12    }    return y*36525/100 - y/100 + y/400 + 306*(m+1)/10 + d - 654842} func repToDay(d, m, y int) int {    if m == 13 {        m--        d += 30    }    if repLeap(y) {        d--    }    return 365*y + (y+1)/4 - (y+1)/100 + (y+1)/400 + 30*m + d - 395} func dayToGre(day int) (d, m, y int) {    y = day * 100 / 36525    d = day - y*36525/100 + 21    y += 1792    d += y/100 - y/400 - 13    m = 8    for d > gregorian[m] {        d -= gregorian[m]        m++        if m == 12 {            m = 0            y++            if greLeap(y) {                gregorian[1] = 29            } else {                gregorian[1] = 28            }        }    }    m++    return} func dayToRep(day int) (d, m, y int) {    y = (day-1) * 100 / 36525    if repLeap(y) {        y--    }    d = day - (y+1)*36525/100 + 365 + (y+1)/100 - (y+1)/400    y++    m = 1    sansculottides := 5    if repLeap(y) {        sansculottides = 6    }    for d > 30 {        d -= 30        m += 1        if m == 13 {            if d > sansculottides {                d -= sansculottides                m = 1                y++                sansculottides = 5                if repLeap(y) {                    sansculottides = 6                }            }        }    }    return} func repLeap(year int) bool {    return (year+1)%4 == 0 && ((year+1)%100 != 0 || (year+1)%400 == 0)} func greLeap(year int) bool {    return year%4 == 0 && (year%100 != 0 || year%400 == 0)}`
`package main import (    "bufio"    "fmt"    "os"    "time"     "frc") func main() {    fmt.Println("*** French  Republican ***")    fmt.Println("*** calendar converter ***")    fmt.Println("Enter a date to convert, in the format 'day month year'")    fmt.Println("e.g.: 1 Prairial 3,")    fmt.Println("      20 May 1795.")    fmt.Println("For Sansculottides, use 'day year'")    fmt.Println("e.g.: Fete de l'opinion 9.")    fmt.Println("Or just press 'RETURN' to exit the program.")    fmt.Println()    for sc := bufio.NewScanner(os.Stdin); ; {        fmt.Print("> ")        sc.Scan()        src := sc.Text()        if src == "" {            return        }        f, ok := frc.Parse(src)        if ok {            fmt.Println(f.ToGregorian())            continue        }        t, err := time.Parse(`2 January 2006`, src)        if err == nil {            fmt.Println(frc.FromGregorian(t.Date()))        }    }}`

## Julia

To stay within historical dates, will throw a domain error if the French Republican date is outside the interval the calendar was actually used.

`using Dates const GC_FORMAT = DateFormat("d U y") const RC_FIRST_DAY = Date(1792, 9, 22) const MAX_RC_DATE = Date(1805, 12, 31) const RC_MONTHS = [    "Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse",    "Germinal", "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor"] const RC_DAYS_IN_MONTH = 30 const RC_SANSCULOTTIDES = [    "Fête de la vertu", "Fête du génie", "Fête du travail",    "Fête de l'opinion", "Fête des récompenses", "Fête de la Révolution"] additionaldaysforyear(yr) = yr > 11 ? 3 : yr > 7 ? 2 : yr > 3 ? 1 : 0additionaldaysformonth(mo) = 30 * (mo - 1)daysforFete(s) = findfirst(x -> x == s, RC_SANSCULOTTIDES) + 359 function togregorian(rc::String)    yearstring, firstpart = reverse.(split(reverse(strip(rc)), r"\s+", limit=2))    rcyear = parse(Int, yearstring)    pastyeardays = (rcyear - 1) * 365 + additionaldaysforyear(rcyear)    if isnumeric(firstpart[1])        daystring, monthstring = split(firstpart, r"\s+", limit=2)        nmonth = findfirst(x -> x == monthstring, RC_MONTHS)        pastmonthdays = 30 * (nmonth - 1)        furtherdays = parse(Int, daystring) + pastmonthdays + pastyeardays - 1    else        furtherdays = daysforFete(firstpart) + pastyeardays    end    gregorian = RC_FIRST_DAY + Day(furtherdays)    if furtherdays < 0 || gregorian > MAX_RC_DATE        throw(DomainError("French Republican Calendar date out of range"))    end    return Day(gregorian).value, monthname(Month(gregorian).value), Year(gregorian).valueend function torepublican(gc::String)    date = Date(DateTime(gc, GC_FORMAT))    if date < RC_FIRST_DAY || date > MAX_RC_DATE        throw(DomainError("French Republican Calendar date out of range"))    end    rcyear, rcdays = divrem(((date - RC_FIRST_DAY).value + 366), 365)    rcdays -= additionaldaysforyear(rcyear)    if rcdays < 1        rcyear -= 1        rcdays += 366    end    if rcdays < 361         nmonth, rcday = divrem(rcdays, 30)        return rcday, RC_MONTHS[nmonth + 1], rcyear    else        return RC_SANSCULOTTIDES[rcdays - 360], rcyear    endend const republican = [    "1 Vendémiaire 1", "1 Prairial 3", "27 Messidor 7",    "Fête de la Révolution 11", "10 Nivôse 14"] const gregorian = [    "22 September 1792", "20 May 1795", "15 July 1799",     "23 September 1803", "31 December 1805"] function testrepublicancalendar()    println("French Republican to Gregorian")    for s in republican        println(lpad(s, 24), " => ", togregorian(s))    end    println("Gregorian to French Republican")    for s in gregorian        println(lpad(s, 24), " => ", torepublican(s))    endend testrepublicancalendar() `
Output:
```French Republican to Gregorian
1 Vendémiaire 1 => (22, "September", 1792)
1 Prairial 3 => (20, "May", 1795)
27 Messidor 7 => (15, "July", 1799)
Fête de la Révolution 11 => (23, "September", 1803)
10 Nivôse 14 => (31, "December", 1805)
Gregorian to French Republican
22 September 1792 => (1, "Vendémiaire", 1)
20 May 1795 => (1, "Prairial", 3)
15 July 1799 => (27, "Messidor", 7)
23 September 1803 => ("Fête de la Révolution", 11)
31 December 1805 => (10, "Nivôse", 14)
```

## Kotlin

`// version 1.1.4-3 import java.time.format.DateTimeFormatterimport java.time.LocalDateimport java.time.temporal.ChronoUnit.DAYS /* year = 1..  month = 1..13  day = 1..30 */ class FrenchRCDate(val year: Int, val month: Int, val day: Int) {     init {        require (year > 0 && month in 1..13)        if (month < 13) require (day in 1..30)        else {            val leap = isLeapYear(year)            require (day in (if (leap) 1..6 else 1..5))        }    }     override fun toString() =        if (month < 13) "\$day \${months[month - 1]} \$year"        else "\${intercal[day - 1]} \$year"     fun toLocalDate(): LocalDate {        var sumDays = 0L        for (i in 1 until year) sumDays += if (isLeapYear(i)) 366 else 365        val dayInYear = (month - 1) * 30 + day - 1        return introductionDate.plusDays(sumDays + dayInYear)    }     companion object {        /* uses the 'continuous method' for years after 1805 */        fun isLeapYear(y: Int): Boolean {            val yy = y + 1            return (yy % 4 == 0) && (yy % 100 != 0 || yy % 400 == 0)        }         fun parse(frcDate: String): FrenchRCDate {            val splits = frcDate.trim().split(' ')            if (splits.size == 3) {                val month = months.indexOf(splits[1]) + 1                require(month in 1..13)                val year = splits[2].toIntOrNull() ?: 0                require(year > 0)                val monthLength = if (month < 13) 30 else if (isLeapYear(year)) 6 else 5                val day = splits[0].toIntOrNull() ?: 0                require(day in 1..monthLength)                return FrenchRCDate(year, month, day)            }            else if (splits.size in 4..5) {                val yearStr = splits[splits.lastIndex]                val year = yearStr.toIntOrNull() ?: 0                require(year > 0)                val scDay = frcDate.trim().dropLast(yearStr.length + 1)                val day = intercal.indexOf(scDay) + 1                val maxDay = if (isLeapYear(year)) 6 else 5                require (day in 1..maxDay)                return FrenchRCDate(year, 13, day)            }            else throw IllegalArgumentException("Invalid French Republican date")        }         /* for convenience we treat 'Sansculottide' as an extra month with 5 or 6 days */        val months = arrayOf(            "Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse", "Germinal",            "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor", "Sansculottide"        )         val intercal = arrayOf(            "Fête de la vertu", "Fête du génie", "Fête du travail",            "Fête de l'opinion", "Fête des récompenses", "Fête de la Révolution"        )         val introductionDate = LocalDate.of(1792, 9, 22)    }} fun LocalDate.toFrenchRCDate(): FrenchRCDate {    val daysDiff  = DAYS.between(FrenchRCDate.introductionDate, this).toInt() + 1    if (daysDiff <= 0) throw IllegalArgumentException("Date can't be before 22 September 1792")    var year = 1    var startDay = 1    while (true) {        val endDay = startDay + if (FrenchRCDate.isLeapYear(year)) 365 else 364        if (daysDiff in startDay..endDay) break        year++        startDay = endDay + 1    }    val remDays = daysDiff - startDay    val month  = remDays / 30    val day = remDays - month * 30    return FrenchRCDate(year, month + 1, day + 1)} fun main(args: Array<String>) {    val formatter = DateTimeFormatter.ofPattern("d MMMM yyyy")    val dates = arrayOf("22 September 1792", "20 May 1795", "15 July 1799", "23 September 1803",                        "31 December 1805", "18 March 1871", "25 August 1944", "19 September 2016",                        "22 September 2017", "28 September 2017")    val frcDates = Array<String>(dates.size) { "" }    for ((i, date) in dates.withIndex()) {        val thisDate = LocalDate.parse(date, formatter)        val frcd = thisDate.toFrenchRCDate()        frcDates[i] = frcd.toString()        println("\${date.padEnd(25)} => \$frcd")    }     // now process the other way around    println()    for (frcDate in frcDates) {        val thisDate = FrenchRCDate.parse(frcDate)        val lds = formatter.format(thisDate.toLocalDate())        println("\${frcDate.padEnd(25)} => \$lds")    }}`
Output:
```22 September 1792         => 1 Vendémiaire 1
20 May 1795               => 1 Prairial 3
15 July 1799              => 27 Messidor 7
23 September 1803         => Fête de la Révolution 11
31 December 1805          => 10 Nivôse 14
18 March 1871             => 27 Ventôse 79
25 August 1944            => 7 Fructidor 152
19 September 2016         => Fête du travail 224
22 September 2017         => 1 Vendémiaire 226
28 September 2017         => 7 Vendémiaire 226

1 Vendémiaire 1           => 22 September 1792
1 Prairial 3              => 20 May 1795
27 Messidor 7             => 15 July 1799
Fête de la Révolution 11  => 23 September 1803
10 Nivôse 14              => 31 December 1805
27 Ventôse 79             => 18 March 1871
7 Fructidor 152           => 25 August 1944
Fête du travail 224       => 19 September 2016
1 Vendémiaire 226         => 22 September 2017
7 Vendémiaire 226         => 28 September 2017
```

## Nim

As was done in Julia version, we have limited the date range to historical dates only.

` import strformat, strscans, strutils, times const   RcMonths = ["Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse",              "Germinal", "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor"]   SansCulottides = ["Fête de la vertu", "Fête du génie", "Fête du travail",                    "Fête de l’opinion", "Fête des récompenses", "Fête de la Révolution"] let  # First and last dates of republican calendar expressed in gregorian calendar.  FirstRcDate = initDateTime(22, mSep, 1792, 0, 0, 0)  LastRcDate = initDateTime(31, mDec, 1805, 0, 0, 0) type  # French republican date representation.  RcDayRange = 1..30  RcMonthRange = 1..13  RcYearRange = 1..14  RepublicanDate = tuple[year: RcYearRange, month: RcMonthRange, day: RcDayRange] # Last dates of republican calendar expressed in republican calendar.const RcLastDate: RepublicanDate = (RcYearRange(14), RcMonthRange(4), RcDayRange(10))  proc notnum(input: string; str: var string; start: int): int =  # Parsing procedure to extract non numerical part of a date.  var i = start  while i <= input.high:    if input[i] in '0'..'9': break    str.add input[i]    inc i  if str.len == 0 or str[^1] != ' ': return -1   # Not terminated by a space.  str.setLen(str.len - 1)   # Back before the space.  result = str.len  proc parseRepublicanDate(rdate: string): RepublicanDate =  ## Parse a French republican date and return its representation.   let date = rdate.strip()  var day, month, year: int  var monthString, dayString: string   if date.scanf("\$i \$+ \$i", day, monthString, year):    # Normal day.    if day notin 1..30:      raise newException(ValueError, "wrong day number: \$1.".format(day))    month = RcMonths.find(monthString) + 1    if month == 0:      raise newException(ValueError, "unknown French republican month: \$1." % monthString)   elif date.scanf("\${notnum} \$i", dayString, year):    # Sans-culottide day (also known as “jour complémentaire”).    month = 13  # Value used for sans-culottide days.    day = SansCulottides.find(dayString) + 1    if day == 0:      raise newException(ValueError, "wrong “sans-culottide” day: « \$1 »." % dayString)    if day == 6 and year mod 4 != 3:      raise newException(ValueError, "republican year \$1 is not a leap year".format(year))   else:    raise newException(ValueError, "invalid French republican date: « \$1 »." % date)   result = (RcYearRange(year), RcMonthRange(month), RcDayRange(day))  if result > RcLastDate:    raise newException(ValueError, "republican date out of range: « \$1 »." % date)  proc `\$`(date: RepublicanDate): string =  ## Return the string representation of a French republican date.   if date.month != 13:    # Normal day.    result = "\$1 \$2 \$3".format(date.day, RcMonths[date.month - 1], date.year)  else:    # Supplementary day.    result = "\$1 \$2".format(SansCulottides[date.day - 1], date.year)  proc toGregorian(rdate: RepublicanDate): DateTime =  ## Convert a republican date tuple to a gregorian date (DateTime object).  let day = (rdate.day - 1) + (rdate.month - 1) * 30 + (rdate.year - 1) * 365 + rdate.year div 4  result = FirstRcDate + initTimeInterval(days = day)  proc toGregorian(rdate: string): string =  ## Convert a republican date string to a gregorian date string.  let date = rdate.parseRepublicanDate()  result = date.toGregorian().format("dd MMMM yyyy")  proc toRepublican(gdate: DateTime): RepublicanDate =  ## Convert a gregorian date (DateTime object) to a republican date tuple.   if gdate notin FirstRcDate..LastRcDate:    raise newException(ValueError, "impossible conversion to republican date.")  let d = gdate - FirstRcDate   # Add a dummy year before year 1 in order to use a four years period.  let dayNumber = d.inDays + 365  let periodNum = dayNumber div 1461  let dayInPeriod = dayNumber mod 1461   # Compute year and day in year.  let yearInPeriod = min(dayInPeriod div 365, 3)  result.year = periodNum * 4 + yearInPeriod  let dayInYear = dayInPeriod - yearInPeriod * 365   # Compute month and day.  result.month = dayInYear div 30 + 1  result.day = dayInYear mod 30 + 1  proc toRepublican(gdate: string): string =  ## Convert a gregorian date string to a republican date string.  let date = gdate.parse("d MMMM yyyy")  result = \$(date.toRepublican())  when isMainModule:   const    RepublicanDates = ["1 Vendémiaire 1", "1 Prairial 3", "27 Messidor 7",                      "Fête de la Révolution 11", "10 Nivôse 14"]    GregorianDates = ["22 September 1792", "20 May 1795", "15 July 1799",                      "23 September 1803", "31 December 1805"]   echo "From French republican dates to gregorian dates:"  for rdate in RepublicanDates:    echo &"{rdate:>24} → {rdate.toGregorian()}"  echo()   echo "From gregorian dates to French republican dates:"  for gdate in GregorianDates:    echo &"{gdate:>24} → {gdate.toRepublican()}"`
Output:
```From French republican dates to gregorian dates:
1 Vendémiaire 1 → 22 September 1792
1 Prairial 3 → 20 May 1795
27 Messidor 7 → 15 July 1799
Fête de la Révolution 11 → 23 September 1803
10 Nivôse 14 → 31 December 1805

From gregorian dates to French republican dates:
22 September 1792 → 1 Vendémiaire 1
20 May 1795 → 1 Prairial 3
15 July 1799 → 27 Messidor 7
23 September 1803 → Fête de la Révolution 11
31 December 1805 → 10 Nivôse 14```

## Perl

`use feature 'state';use DateTime;my @month_names = qw{    Vendémiaire Brumaire Frimaire  Nivôse   Pluviôse  Ventôse    Germinal    Floréal  Prairial  Messidor Thermidor Fructidor};my @intercalary = (    'Fête de la vertu',  'Fête du génie',        'Fête du travail',    "Fête de l'opinion", 'Fête des récompenses', 'Fête de la Révolution',);my %month_nums  = map { \$month_names[\$_] => \$_+1 } 0 .. \$#month_names;my %i_cal_nums  = map { \$intercalary[\$_] => \$_+1 } 0 .. \$#intercalary;my \$i_cal_month = 13;my \$epoch       = DateTime->new( year => 1792, month => 9, day => 22 ); sub is_republican_leap_year {    my \$y = \$_[0] + 1;    return !!( (\$y % 4)==0 and ((\$y % 100)!=0 or (\$y % 400)==0) );} sub Republican_to_Gregorian {    my (\$rep_date) = @_;    state \$months   = join '|', map { quotemeta } @month_names;    state \$intercal = join '|', map { quotemeta } @intercalary;    state \$re = qr{      \A        \s* (?:                (?<ic> \$intercal)              | (?<day> \d+) \s+ (?<month> \$months)            )        \s+ (?<year> \d+)        \s*      \z    }msx;     \$rep_date =~ /\$re/        or die "Republican date not recognized: '\$rep_date'";     my \$day1   = \$+{ic}    ? \$i_cal_nums{\$+{ic}}    : \$+{day};    my \$month1 = \$+{month} ? \$month_nums{\$+{month}} : \$i_cal_month;    my \$year1  = \$+{year};     my \$days_since_epoch = (\$year1-1) * 365 + (\$month1-1) * 30 + (\$day1-1);     my \$leap_days = grep { is_republican_leap_year(\$_) } 1 .. \$year1-1;    return \$epoch->clone->add( days => (\$days_since_epoch + \$leap_days) );} sub Gregorian_to_Republican {    my (\$greg_date) = @_;     my \$days_since_epoch = \$epoch->delta_days(\$greg_date)->in_units('days');    die if \$days_since_epoch < 0;    my ( \$year, \$days ) = ( 1, \$days_since_epoch );    while (1) {        my \$year_length = 365 + ( is_republican_leap_year(\$year) ? 1 : 0 );        last if \$days < \$year_length;        \$days -= \$year_length;        \$year += 1;    }    my \$day0   = \$days % 30;    my \$month0 = (\$days - \$day0) / 30;     my ( \$day1, \$month1 ) = ( \$day0 + 1, \$month0 + 1 );     return \$month1 == \$i_cal_month        ?       "\$intercalary[\$day0  ] \$year"        : "\$day1 \$month_names[\$month0] \$year";} while (<DATA>) {    s{\s*\#.+\n?\z}{};    /^(\d{4})-(\d{2})-(\d{2})\s+(\S.+?\S)\s*\$/ or die;     my \$g = DateTime->new( year => \$1, month => \$2, day => \$3 );    my \$r = \$4;     die if Republican_to_Gregorian(\$r) != \$g        or Gregorian_to_Republican(\$g) ne \$r;     die if Gregorian_to_Republican(Republican_to_Gregorian(\$r)) ne \$r        or Republican_to_Gregorian(Gregorian_to_Republican(\$g)) != \$g;}say 'All tests successful.'; __DATA__1792-09-22  1 Vendémiaire 11795-05-20  1 Prairial 31799-07-15  27 Messidor 71803-09-23  Fête de la Révolution 111805-12-31  10 Nivôse 141871-03-18  27 Ventôse 791944-08-25  7 Fructidor 1522016-09-19  Fête du travail 2241871-05-06  16 Floréal 79   # Paris Commune begins1871-05-23  3 Prairial 79   # Paris Commune ends1799-11-09  18 Brumaire 8   # Revolution ends by Napoléon coup1804-12-02  11 Frimaire 13  # Republic   ends by Napoléon coronation1794-10-30  9 Brumaire 3    # École Normale Supérieure established1794-07-27  9 Thermidor 2   # Robespierre falls1799-05-27  8 Prairial 7    # Fromental Halévy born1792-09-22  1 Vendémiaire 11793-09-22  1 Vendémiaire 21794-09-22  1 Vendémiaire 31795-09-23  1 Vendémiaire 41796-09-22  1 Vendémiaire 51797-09-22  1 Vendémiaire 61798-09-22  1 Vendémiaire 71799-09-23  1 Vendémiaire 81800-09-23  1 Vendémiaire 91801-09-23  1 Vendémiaire 101802-09-23  1 Vendémiaire 111803-09-24  1 Vendémiaire 121804-09-23  1 Vendémiaire 131805-09-23  1 Vendémiaire 141806-09-23  1 Vendémiaire 151807-09-24  1 Vendémiaire 161808-09-23  1 Vendémiaire 171809-09-23  1 Vendémiaire 181810-09-23  1 Vendémiaire 191811-09-24  1 Vendémiaire 202015-09-23  1 Vendémiaire 2242016-09-22  1 Vendémiaire 2252017-09-22  1 Vendémiaire 226 `
Output:
`All tests successful.`

## Phix

`constant gregorians = {"January", "February", "March", "April", "May", "June", "July",                        "August", "September", "October", "November", "December"},         gregorian = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},         republicans = {"Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse",                         "Ventôse", "Germinal", "Floréal", "Prairial", "Messidor",                         "Thermidor", "Fructidor"},         sansculottides = {"Fête de la vertu", "Fête du génie", "Fête du travail",                           "Fête de l'opinion", "Fête des récompenses",                           "Fête de la Révolution"} function rep_leap(integer year)    return mod(year+1,4)==0 and (mod(year+1,100)!=0 or mod(year+1,400)==0)end function function rep_to_day(sequence dmy)    integer {d, m, y} = dmy    if m == 13 then        m -= 1        d += 30    end if    if rep_leap(y) then        d -= 1    end if    integer res = 365*(y-1) + floor((y+1)/4) - floor((y+1)/100) + floor((y+1)/400) + 30*(m-1) + d    return resend function function gre_leap(integer year)    return mod(year,4)==0 and (mod(year,100)!=0 or mod(year,400)==0)end function function gre_to_day(sequence dmy)    integer {d, m, y} = dmy    if m < 3 then        y -= 1        m += 12    end if    integer res =  floor(y*365.25) - floor(y/100) + floor(y/400)                 + floor(30.6*(m+1)) + d - 654842    return resend function function day_to_rep(integer day)    integer y = floor((day-1)/365.25)    if not rep_leap(y) then        y += 1    end if    integer d = day - floor(y*365.25) + 365 + floor(y/100) - floor(y/400),            m = 1,            sansculottide = 5+rep_leap(y)    while d>30 do        d -= 30        m += 1        if m == 13 then            if d > sansculottide then                d -= sansculottide                m = 1                y += 1                sansculottide = 5 + rep_leap(y)            end if        end if    end while    return {d,m,y}end function function day_to_gre(integer day)    integer y = floor(day/365.25),            d = day - floor(y*365.25) + 21,            m = 9    y += 1792    d += floor(y/100) - floor(y/400) - 13    sequence gregoriam = gregorian  -- (modifiable copy)    while d>gregoriam[m] do        d -= gregoriam[m]        m += 1        if m == 13 then            m = 1            y += 1            gregoriam[2] = 28 + gre_leap(y)        end if    end while    return {d,m,y}end function function greg_to_frep(string greg)    {{integer day, string months, integer year}} = scanf(greg,"%d %s %d")    integer month = find(months,gregorians)    {day,month,year} = day_to_rep(gre_to_day({day,month,year}))    string frep = iff(month=13?sprintf("%s %d",{sansculottides[day], year})                              :sprintf("%d %s %d",{day, republicans[month], year}))    return frepend function     function frep_to_greg(string frep)    integer day, month, year    if frep[1]<='9' then        {{day, string months, year}} = scanf(frep,"%d %s %d")        month = find(months,republicans)    else        {{string days, year}} = scanf(frep,"%s %d")        day = find(days,sansculottides)        month = 13    end if    {day,month,year} = day_to_gre(rep_to_day({day, month, year}))    string greg = sprintf("%02d %s %d",{day, gregorians[month], year})    return gregend function constant test_data = {                      { "22 September 1792", "1 Vendémiaire 1" },                      { "20 May 1795", "1 Prairial 3" },                      { "15 July 1799", "27 Messidor 7" },                      { "23 September 1803", "Fête de la Révolution 11" },                      { "31 December 1805", "10 Nivôse 14" },                       { "18 March 1871", "27 Ventôse 79" },                      { "25 August 1944", "7 Fructidor 152" },                      { "19 September 2016", "Fête du travail 224" },                       { "06 May 1871", "16 Floréal 79" },       -- Paris Commune begins                      { "23 May 1871", "3 Prairial 79" },       -- Paris Commune ends                      { "09 November 1799", "18 Brumaire 8" },  -- Revolution ends by Napoléon coup                      { "02 December 1804", "11 Frimaire 13" }, -- Republic ends by Napoléon coronation                      { "30 October 1794", "9 Brumaire 3" },    -- École Normale Supérieure established                      { "27 July 1794", "9 Thermidor 2" },      -- Robespierre falls                      { "27 May 1799", "8 Prairial 7" },        -- Fromental Halévy born                       { "22 September 1792", "1 Vendémiaire 1" },                      { "22 September 1793", "1 Vendémiaire 2" },                      { "22 September 1794", "1 Vendémiaire 3" },                      { "23 September 1795", "1 Vendémiaire 4" },                      { "22 September 1796", "1 Vendémiaire 5" },                      { "22 September 1797", "1 Vendémiaire 6" },                      { "22 September 1798", "1 Vendémiaire 7" },                      { "23 September 1799", "1 Vendémiaire 8" },                      { "23 September 1800", "1 Vendémiaire 9" },                      { "23 September 1801", "1 Vendémiaire 10" },                      { "23 September 1802", "1 Vendémiaire 11" },                      { "24 September 1803", "1 Vendémiaire 12" },                      { "23 September 1804", "1 Vendémiaire 13" },                      { "23 September 1805", "1 Vendémiaire 14" },                      { "23 September 1806", "1 Vendémiaire 15" },                      { "24 September 1807", "1 Vendémiaire 16" },                      { "23 September 1808", "1 Vendémiaire 17" },                      { "23 September 1809", "1 Vendémiaire 18" },                      { "23 September 1810", "1 Vendémiaire 19" },                      { "24 September 1811", "1 Vendémiaire 20" },                      { "23 September 2015", "1 Vendémiaire 224" },                      { "21 September 2016", "Fête des récompenses 224" },                      { "22 September 2016", "1 Vendémiaire 225" },                      { "23 September 2016", "2 Vendémiaire 225" },                      { "22 September 2017", "1 Vendémiaire 226" },                      { "28 September 2017", "7 Vendémiaire 226" } } for i=1 to length(test_data) do    string {greg, frep} = test_data[i],           frep2 = greg_to_frep(greg),           greg2 = frep_to_greg(frep),           ok = iff(frep=frep2 and greg=greg2?"ok":"**** ERROR ****")    if platform()=WINDOWS then        -- the windows console does not handle         -- non-basic-latin-ascii characters well...        frep = substitute_all(frep,"éêéô","eeeo")    end if    printf(1,"%18s <==> %-25s %s\n",{greg,frep,ok})end for --sanity test:for i=1 to 150000 do -- (years 1792..~2203)    if rep_to_day(day_to_rep(i))!=i then ?9/0 end if    if gre_to_day(day_to_gre(i))!=i then ?9/0 end ifend for`
Output:
``` 22 September 1792 <==> 1 Vendemiaire 1           ok
20 May 1795 <==> 1 Prairial 3              ok
15 July 1799 <==> 27 Messidor 7             ok
23 September 1803 <==> Fete de la Revolution 11  ok
31 December 1805 <==> 10 Nivose 14              ok
18 March 1871 <==> 27 Ventose 79             ok
25 August 1944 <==> 7 Fructidor 152           ok
19 September 2016 <==> Fete du travail 224       ok
06 May 1871 <==> 16 Floreal 79             ok
23 May 1871 <==> 3 Prairial 79             ok
09 November 1799 <==> 18 Brumaire 8             ok
02 December 1804 <==> 11 Frimaire 13            ok
30 October 1794 <==> 9 Brumaire 3              ok
27 July 1794 <==> 9 Thermidor 2             ok
27 May 1799 <==> 8 Prairial 7              ok
22 September 1792 <==> 1 Vendemiaire 1           ok
22 September 1793 <==> 1 Vendemiaire 2           ok
22 September 1794 <==> 1 Vendemiaire 3           ok
23 September 1795 <==> 1 Vendemiaire 4           ok
22 September 1796 <==> 1 Vendemiaire 5           ok
22 September 1797 <==> 1 Vendemiaire 6           ok
22 September 1798 <==> 1 Vendemiaire 7           ok
23 September 1799 <==> 1 Vendemiaire 8           ok
23 September 1800 <==> 1 Vendemiaire 9           ok
23 September 1801 <==> 1 Vendemiaire 10          ok
23 September 1802 <==> 1 Vendemiaire 11          ok
24 September 1803 <==> 1 Vendemiaire 12          ok
23 September 1804 <==> 1 Vendemiaire 13          ok
23 September 1805 <==> 1 Vendemiaire 14          ok
23 September 1806 <==> 1 Vendemiaire 15          ok
24 September 1807 <==> 1 Vendemiaire 16          ok
23 September 1808 <==> 1 Vendemiaire 17          ok
23 September 1809 <==> 1 Vendemiaire 18          ok
23 September 1810 <==> 1 Vendemiaire 19          ok
24 September 1811 <==> 1 Vendemiaire 20          ok
23 September 2015 <==> 1 Vendemiaire 224         ok
21 September 2016 <==> Fete des recompenses 224  ok
22 September 2016 <==> 1 Vendemiaire 225         ok
23 September 2016 <==> 2 Vendemiaire 225         ok
22 September 2017 <==> 1 Vendemiaire 226         ok
28 September 2017 <==> 7 Vendemiaire 226         ok
```

## Raku

(formerly Perl 6)

`use v6;constant @month_names = <    Vendémiaire Brumaire Frimaire  Nivôse   Pluviôse  Ventôse    Germinal    Floréal  Prairial  Messidor Thermidor Fructidor>;constant @intercalary =    'Fête de la vertu',  'Fête du génie',        'Fête du travail',    "Fête de l'opinion", 'Fête des récompenses', 'Fête de la Révolution',;constant %month_nums  = %( @month_names Z=> 1..12 );constant %i_cal_nums  = %( @intercalary Z=> 1.. 6 );constant \$i_cal_month = 13;constant \$epoch       = Date.new: '1792-09-22'; sub is_republican_leap_year ( Int:D \$year --> Bool ) {    my \$y := \$year + 1;    return ?( \$y %% 4 and (\$y !%% 100 or \$y %% 400) );} sub Republican_to_Gregorian ( Str:D \$rep_date --> Date ) {    grammar Republican_date_text {        token day   { \d+ }        token year  { \d+ }        token ic    { @intercalary }        token month { @month_names }        rule TOP    { ^ [ <ic> | <day> <month> ] <year> \$ }    }     Republican_date_text.parse(\$rep_date)        orelse die "Republican date not recognized: '\$rep_date'";     my \$day1   := \$/<ic>    ?? %i_cal_nums{~\$/<ic>}    !! +\$/<day>;    my \$month1 := \$/<month> ?? %month_nums{~\$/<month>} !! \$i_cal_month;     my @ymd0 := (\$/<year>, \$month1, \$day1) »-» 1;    my \$days_since_epoch := [+] @ymd0 Z* (365, 30, 1);     my \$leap_days := +grep &is_republican_leap_year, 1 ..^ \$/<year>;    return \$epoch + \$days_since_epoch + \$leap_days;} sub Gregorian_to_Republican ( Date:D \$greg_date --> Str ) {    my \$days_since_epoch := \$greg_date - \$epoch;    die if \$days_since_epoch < 0;     my ( \$year, \$days ) = 1, \$days_since_epoch;    loop {        my \$year_length = 365 + (1 if \$year.&is_republican_leap_year);        last if \$days < \$year_length;        \$days -= \$year_length;        \$year += 1;    }     my ( \$day0, \$month0 ) = \$days.polymod( 30 );    my ( \$day1, \$month1 ) = (\$day0, \$month0) X+ 1;     return \$month1 == \$i_cal_month        ??       "@intercalary[\$day0  ] \$year"        !! "\$day1 @month_names[\$month0] \$year";} my @test_data =    ( '1792-09-22', '1 Vendémiaire 1' ),    ( '1795-05-20', '1 Prairial 3' ),    ( '1799-07-15', '27 Messidor 7' ),    ( '1803-09-23', 'Fête de la Révolution 11' ),    ( '1805-12-31', '10 Nivôse 14' ),     ( '1871-03-18', '27 Ventôse 79' ),    ( '1944-08-25', '7 Fructidor 152' ),    ( '2016-09-19', 'Fête du travail 224' ),     ( '1871-05-06', '16 Floréal 79'  ), # Paris Commune begins    ( '1871-05-23', '3 Prairial 79'  ), # Paris Commune ends    ( '1799-11-09', '18 Brumaire 8'  ), # Revolution ends by Napoléon coup    ( '1804-12-02', '11 Frimaire 13' ), # Republic   ends by Napoléon coronation    ( '1794-10-30', '9 Brumaire 3'   ), # École Normale Supérieure established    ( '1794-07-27', '9 Thermidor 2'  ), # Robespierre falls    ( '1799-05-27', '8 Prairial 7'   ), # Fromental Halévy born     ( '1792-09-22', '1 Vendémiaire 1'   ),    ( '1793-09-22', '1 Vendémiaire 2'   ),    ( '1794-09-22', '1 Vendémiaire 3'   ),    ( '1795-09-23', '1 Vendémiaire 4'   ),    ( '1796-09-22', '1 Vendémiaire 5'   ),    ( '1797-09-22', '1 Vendémiaire 6'   ),    ( '1798-09-22', '1 Vendémiaire 7'   ),    ( '1799-09-23', '1 Vendémiaire 8'   ),    ( '1800-09-23', '1 Vendémiaire 9'   ),    ( '1801-09-23', '1 Vendémiaire 10'  ),    ( '1802-09-23', '1 Vendémiaire 11'  ),    ( '1803-09-24', '1 Vendémiaire 12'  ),    ( '1804-09-23', '1 Vendémiaire 13'  ),    ( '1805-09-23', '1 Vendémiaire 14'  ),    ( '1806-09-23', '1 Vendémiaire 15'  ),    ( '1807-09-24', '1 Vendémiaire 16'  ),    ( '1808-09-23', '1 Vendémiaire 17'  ),    ( '1809-09-23', '1 Vendémiaire 18'  ),    ( '1810-09-23', '1 Vendémiaire 19'  ),    ( '1811-09-24', '1 Vendémiaire 20'  ),    ( '2015-09-23', '1 Vendémiaire 224' ),    ( '2016-09-22', '1 Vendémiaire 225' ),    ( '2017-09-22', '1 Vendémiaire 226' ),; for @test_data -> ( \$g_text, \$r ) {    my \$g = Date.new: \$g_text;     die if Republican_to_Gregorian(\$r) != \$g        or Gregorian_to_Republican(\$g) ne \$r;     die if Gregorian_to_Republican(Republican_to_Gregorian(\$r)) ne \$r        or Republican_to_Gregorian(Gregorian_to_Republican(\$g)) != \$g;}say 'All tests successful.';`
Output:
`All tests successful.`

## Sidef

Translation of: Perl
`require('DateTime') var month_names = %w(  Vendémiaire Brumaire Frimaire  Nivôse   Pluviôse  Ventôse  Germinal    Floréal  Prairial  Messidor Thermidor Fructidor) var intercalary = [                   'Fête de la vertu',                   'Fête du génie',                   'Fête du travail',                   "Fête de l'opinion",                   'Fête des récompenses',                   'Fête de la Révolution',                  ] var i_cal_month = 13var epoch = %O<DateTime>.new(year => 1792, month => 9, day => 22) var month_nums = Hash(month_names.kv.map {|p| [p[1], p[0]+1] }.flat...)var i_cal_nums = Hash(intercalary.kv.map {|p| [p[1], p[0]+1] }.flat...) func is_republican_leap_year(Number year) -> Bool {    var y = (year + 1)    !!(4.divides(y) && (!100.divides(y) || 400.divides(y)))} func Republican_to_Gregorian(String rep_date) -> String {    static months   = month_names.map { .escape }.join('|')    static intercal = intercalary.map { .escape }.join('|')    static re       = Regex("^        \\s* (?:                (?<ic> #{intercal})              | (?<day> \\d+) \\s+ (?<month> #{months})            )        \\s+ (?<year> \\d+)        \\s*      \\z", 'x')     var m = (rep_date =~ re)    m || die "Republican date not recognized: '#{rep_date}'"     var ncap = m.named_captures     var day1   = Number(ncap{:ic}    ? i_cal_nums{ncap{:ic}}    : ncap{:day})    var month1 = Number(ncap{:month} ? month_nums{ncap{:month}} : i_cal_month)    var year1  = Number(ncap{:year})     var days_since_epoch = (365*(year1 - 1) + 30*(month1 - 1) + (day1 - 1))     var leap_days = (1 ..^ year1 -> grep { is_republican_leap_year(_) })    epoch.clone.add(days => (days_since_epoch + leap_days)).strftime("%Y-%m-%d")} func Gregorian_to_Republican(String greg_date) -> String {    var m = (greg_date =~ /^(\d{4})-(\d{2})-(\d{2})\z/)    m || die "Gregorian date not recognized: '#{greg_date}'"     var g = %O<DateTime>.new(year => m[0], month => m[1], day => m[2])    var days_since_epoch = epoch.delta_days(g).in_units('days')    days_since_epoch < 0 && die "unexpected error"    var (year, days) = (1, days_since_epoch)     loop {        var year_length = (365 + (is_republican_leap_year(year) ? 1 : 0))        days < year_length && break        days -= year_length        year += 1;    }     var day0   = (days % 30)    var month0 = (days - day0)/30     var (day1, month1) = (day0 + 1, month0 + 1)     (month1 == i_cal_month        ? "#{intercalary[day0]} #{year}"        : "#{day1} #{month_names[month0]} #{year}")} for line in DATA {     line.sub!(/\s*\#.+\R?\z/, '')     var m = (line =~ /^(\d{4})-(\d{2})-(\d{2})\s+(\S.+?\S)\s*\$/)    m || die "error for: #{line.dump}"     var g = "#{m[0]}-#{m[1]}-#{m[2]}"    var r = m[3]     var r2g = Republican_to_Gregorian(r)    var g2r = Gregorian_to_Republican(g)     #say "#{r} -> #{r2g}"    #say "#{g} -> #{g2r}"     if ((g2r != r) || (r2g != g)) {        die "1-way error"    }     if ((Gregorian_to_Republican(r2g) != r) ||        (Republican_to_Gregorian(g2r) != g)    ) {        die "2-way error"    }} say 'All tests successful.' __DATA__1792-09-22  1 Vendémiaire 11795-05-20  1 Prairial 31799-07-15  27 Messidor 71803-09-23  Fête de la Révolution 111805-12-31  10 Nivôse 141871-03-18  27 Ventôse 791944-08-25  7 Fructidor 1522016-09-19  Fête du travail 2241871-05-06  16 Floréal 79   # Paris Commune begins1871-05-23  3 Prairial 79   # Paris Commune ends1799-11-09  18 Brumaire 8   # Revolution ends by Napoléon coup1804-12-02  11 Frimaire 13  # Republic   ends by Napoléon coronation1794-10-30  9 Brumaire 3    # École Normale Supérieure established1794-07-27  9 Thermidor 2   # Robespierre falls1799-05-27  8 Prairial 7    # Fromental Halévy born1792-09-22  1 Vendémiaire 11793-09-22  1 Vendémiaire 21794-09-22  1 Vendémiaire 31795-09-23  1 Vendémiaire 41796-09-22  1 Vendémiaire 51797-09-22  1 Vendémiaire 61798-09-22  1 Vendémiaire 71799-09-23  1 Vendémiaire 81800-09-23  1 Vendémiaire 91801-09-23  1 Vendémiaire 101802-09-23  1 Vendémiaire 111803-09-24  1 Vendémiaire 121804-09-23  1 Vendémiaire 131805-09-23  1 Vendémiaire 141806-09-23  1 Vendémiaire 151807-09-24  1 Vendémiaire 161808-09-23  1 Vendémiaire 171809-09-23  1 Vendémiaire 181810-09-23  1 Vendémiaire 191811-09-24  1 Vendémiaire 202015-09-23  1 Vendémiaire 2242016-09-22  1 Vendémiaire 2252017-09-22  1 Vendémiaire 226`
Output:
```All tests successful.
```

## Wren

Translation of: Kotlin
Library: Wren-date
Library: Wren-seq
Library: Wren-fmt
`import "/date" for Dateimport "/seq" for Lstimport "/fmt" for Fmt class FrenchRCDate {    /* uses the 'continuous method' for years after 1805 */    static isLeapYear(y) {        var yy = y + 1         return (yy % 4 == 0) && (yy % 100 != 0 || yy % 400 == 0)    }     static parse(frcDate) {        var splits = frcDate.trim().split(" ")        if (splits.count == 3) {            var month = Lst.indexOf(months, splits[1]) + 1            if (month < 1 || month > 13) Fiber.abort("Invalid month.")            var year = Num.fromString(splits[2])            if (year < 1) Fiber.abort("Invalid year.")            var monthLength = (month < 13) ? 30 : (isLeapYear(year) ? 6 : 5)            var day = Num.fromString(splits[0])            if (day < 1 || day > monthLength) Fiber.abort("Invalid day.")            return FrenchRCDate.new(year, month, day)        } else if (splits.count == 4 || splits.count == 5) {            var yearStr = splits[-1]            var year = Num.fromString(yearStr)            if (year < 1) Fiber.abort("Invalid year.")            var scDay = frcDate.trim()[0...-(yearStr.count + 1)]            var day = Lst.indexOf(intercal, scDay) + 1            var maxDay = isLeapYear(year) ? 6 : 5            if (day < 1 || day > maxDay) Fiber.abort("Invalid day.")            return FrenchRCDate.new(year, 13, day)         } else Fiber.abort("Invalid French Republican date.")    }     /* for convenience we treat 'Sansculottide' as an extra month with 5 or 6 days */    static months {        return ["Vendémiaire", "Brumaire", "Frimaire", "Nivôse", "Pluviôse", "Ventôse", "Germinal",                "Floréal", "Prairial", "Messidor", "Thermidor", "Fructidor", "Sansculottide"]    }     static intercal {        return ["Fête de la vertu", "Fête du génie", "Fête du travail",                "Fête de l'opinion", "Fête des récompenses", "Fête de la Révolution"]    }     static introductionDate { Date.new(1792, 9, 22) }     /* year = 1..  month = 1..13  day = 1..30 */    construct new(year, month, day) {        if (year <= 0 || month < 1 || month > 13) Fiber.abort("Invalid date.")        if (month < 13) {            if (day < 1 || day > 30)  Fiber.abort("Invalid date.")        } else {            var leap = FrenchRCDate.isLeapYear(year)            if (leap  && (day < 1 || day > 6)) Fiber.abort("Invalid date.")            if (!leap && (day < 1 || day > 5)) Fiber.abort("Invalid date.")        }        _year = year        _month = month        _day = day    }     static fromLocalDate(ldate) {        var daysDiff = (ldate - introductionDate).days + 1        if (daysDiff <= 0) Fiber.abort("Date can't be before 22 September 1792.")        var year = 1        var startDay = 1        while (true) {            var endDay = startDay + (isLeapYear(year) ? 365 : 364)            if (daysDiff >= startDay && daysDiff <= endDay) break            year = year + 1            startDay = endDay + 1        }        var remDays = daysDiff - startDay        var month  = (remDays / 30).floor        var day = remDays - month * 30        return FrenchRCDate.new(year, month + 1, day + 1)    }     toString {        if (_month < 13) return "%(_day) %(FrenchRCDate.months[_month - 1]) %(_year)"        return "%(FrenchRCDate.intercal[_day - 1]) %(_year)"    }     toLocalDate {        var sumDays = 0        for (i in 1..._year) sumDays = sumDays + (FrenchRCDate.isLeapYear(i) ? 366 : 365)        var dayInYear = (_month - 1) * 30 + _day - 1        return FrenchRCDate.introductionDate.addDays(sumDays + dayInYear)    }} var fmt = "d| |mmmm| |yyyy"var dates = [     "22 September 1792", "20 May 1795", "15 July 1799", "23 September 1803",     "31 December 1805", "18 March 1871", "25 August 1944", "19 September 2016",     "22 September 2017", "28 September 2017"]var frcDates = List.filled(dates.count, null)var i = 0for (date in dates) {    var thisDate = Date.parse(date, fmt)    var frcd = FrenchRCDate.fromLocalDate(thisDate)    frcDates[i] = frcd.toString    Fmt.print("\$-25s => \$s", date, frcd)    i = i + 1} // now process the other way aroundSystem.print()for (frcDate in frcDates) {    var thisDate = FrenchRCDate.parse(frcDate)    var lds = thisDate.toLocalDate.format(fmt)    Fmt.print("\$-25s => \$s", frcDate, lds)}`
Output:
```22 September 1792         => 1 Vendémiaire 1
20 May 1795               => 1 Prairial 3
15 July 1799              => 27 Messidor 7
23 September 1803         => Fête de la Révolution 11
31 December 1805          => 10 Nivôse 14
18 March 1871             => 27 Ventôse 79
25 August 1944            => 7 Fructidor 152
19 September 2016         => Fête du travail 224
22 September 2017         => 1 Vendémiaire 226
28 September 2017         => 7 Vendémiaire 226

1 Vendémiaire 1           => 22 September 1792
1 Prairial 3              => 20 May 1795
27 Messidor 7             => 15 July 1799
Fête de la Révolution 11  => 23 September 1803
10 Nivôse 14              => 31 December 1805
27 Ventôse 79             => 18 March 1871
7 Fructidor 152           => 25 August 1944
Fête du travail 224       => 19 September 2016
1 Vendémiaire 226         => 22 September 2017
7 Vendémiaire 226         => 28 September 2017
```