OS/2 Shareware BBS: 10 Tools/10-Tools.zip/hcshdemo.zip/csh-os2.zip/SAMPLES/CALENDAR.CSH

Text File | 1993-09-28 | 3KB | 92 lines

#    Print a calendar for the specified month, highlighting today's date.
#    Based on algorithms published in Computer Language magazine,
#    December, 1990.  Used with permission.

proc day(jdate)
    # Calculate the day of the month corresponding to a Julian day number.
    local a, b, c, d, e, z, alpha
    @ z = jdate + 1
    # Cope with the Gregorian calendar reform.
    if (z < 2299161) then
        @ a = z
    else
        @ alpha = (z - 1867216.25)//36524.25
        @ a = z + 1 + alpha - alpha//4
    end
    @ b = a + 1524
    @ c = (b - 122.1)//365.25
    @ d = floor(365.25 * c)
    @ e = (b - d)//30.6001
    return b - d - floor(30.6001 * e)
end

proc dayofweek(jdate)
    return (jdate + 2) % 7
end

proc calendar(month, year)
    # Print a calendar for the specified month
    local b_date, e_date, c_date, day, c_day, c_month, c_year, Month, week
    local m, d, y, i, today
    set Month = January February March April May June ^
        July August September October November December
    set dt = `dt`
    set m = $dt:1
    set d = $dt:2
    set y = $dt:3
    for i = 0 to 11 do
        if (m == substr(Month[i], 1, 3)) break
    end
    @ m = i + 1
    @ today = `julian $m $d $y`
    if (year == '') then
        @ year = y
        if (month == '') @ month = m
    end
    if (month !~ '[0-9]*') then
        @ m = "$lower(month)*"
        for i = 0 to 11 do
            if (lower(Month[i]) =~ m) break
        end
        @ month = i + 1
    end
    # Calculate Julian day numbers for the first and last days of the month
    if ((b_date = julian(month, 1, year)) == -1) return
    @ e_date = (month < 12 ? ^
            julian(month + 1, 1, year) : ^
            julian(1, 1, year == -1 ? 1 : year + 1)) - 1
    echo $Month[month - 1] $year
    @ week = "^r^nSun Mon Tue Wed Thu Fri Sat^r^n"
    # Put the first day of the month under the correct day column
    for i = 0 to day = dayofweek(b_date) - 1 do
        @ week = concat(week, "    ")
    end
    # Print all the days
    @ i = 1
    if (b_date == 2299156) then
        #    In October 1582, the Julian calendar was replaced with the
        #    Gregorian calendar and Oct 4 was immediately followed by Oct 15
        #    by decree of Pope Gregory XIII.  However, be aware that Britain
        #    did not adopt the Gregorian calendar until Sept 2, 1752 (which
        #    was followed by Sept 14.)  This routine prints a calendar according
        #    to Pope Gregory's decree.
        for c_date = b_date to e_date do
            @ week = concat(week, printf("%3d ", i++))
            if (i == 5) @ i = 15
            if (c_date != e_date && ++day % 7 == 6) @ week = concat(week, "^r^n")
        end
    else
        for c_date = b_date to e_date do
            @ week = (today == c_date) ?                ^
                concat(week, ansi("bright yellow"),    ^
                    printf("%3d ", i++), ansi()) :    ^
                concat(week, printf("%3d ", i++))
            if (c_date != e_date && ++day % 7 == 6) @ week = concat(week, "^r^n")
        end
    end
    calc week
    echo
end

calendar $argv