Announcement

**webultra** · 09-08-2014, 12:09 AM

I saw this post and just wanted to write an alternative in OOP.

HMM, you should try to work with dates as strings.

I wrote 2 "diff" functions (with different results) and also a way to guess the date format for US dates by using lua patterns.

NOTE: I have tested the code with the supplied examples.

PHP Code:


Date = {

    -- Class variable shared across all objects

    def = {

        year = {Y = {length=4}, y = {length = 2} },

        month = {m = {length = 2}},

        day = {d = {length = 2}},

        hour = {H = {length = 2}, h = {length = 2}},

        min = {M = {length = 2}},

        sec = {S = {length = 2}}

    },

    times = {

        years = 365.25*24*60*60,

        months = 30*24*60*60,

        days = 24*60*60,

        hours = 60*60,

        minutes = 60,

        seconds = 1

    },

    specialFormats = {

        '(%d%d?)[%/%-](%d%d?)[%/%-](%d%d%d%d)', -- MM[/-]DD[/-]YYYY

        '(%w+)%s(%d%d?),%s(%d%d)', -- Month D, YY

        '%w+, (%w+)%s(%d%d?),%s(%d%d)' -- DayOfWeek, Month D, YY

    },

    months = {January = '01',February = '02',March = '03',April = '04',May = '05',June = '06',July = '07',August = '08',September = '09',October = '10',November = '11',December = '12'}

}



function Date.new(date, format)

    local self = {}

    if ( type(date) == 'number' ) then

        self.timestamp = date;

    elseif type(date) == 'string' then

        local tableTime = {};

        if not format then

            local found = false;

            for k, special in pairs(Date.specialFormats) do

                date = date:gsub(special, function(month, day, year)

                    local f = {(#year==2) and 'y' or "Y", "m","d"}

                    format = table.concat(f, "-");

                    found = true;

                    return year.."-"..Date.months[month].."-"..day

                end)

                if found then break end

            end

            print(format, date)

            format = format or 'Y-m-d H:M:s'

        end

        format:gsub("%w", function(letter)

            for tipo, formatos in pairs(Date.def) do

                for i, formato in pairs(formatos) do

                    if i == letter then

                        date = date:gsub(string.rep("%d", formato.length), function(number)

                            number = tonumber(number)

                            if ( i == "y") then

                                if (number >= 70 and number <= 99 ) then

                                    number = number + 1900

                                else

                                    number = number + 2000

                                end

                            end

                            tableTime[tipo] = number

                            return ""

                        end, 1)

                        break;

                    end

                end

            end

            return letter;

        end)

        self.timestamp = os.time(tableTime)

    else

        self.timestamp = os.time()

    end



    function self.diff(date2)

        local diffInSeconds = date2.timestamp-self.timestamp;

        local constant = diffInSeconds;

        local m = (diffInSeconds < 0) and -1 or 1;

        local times = {

            years = 0,

            months = 0,

            days = 0,

            hours = 0,

            minutes = 0,

            seconds = 0,

        }

        function times.get(kind)

            return times[kind];

        end

        function times.getTotal(kind)

            return times["t_"..kind];

        end



        for i, kind in pairs({'years', 'months', 'days', 'hours', 'minutes', 'seconds'}) do

            local t = constant/Date.times[kind]

            local n = diffInSeconds/Date.times[kind]

            local absolute = math.abs(n)

            local value = math.floor(absolute);

            if ( absolute > 1) then

                times[kind] = n / Date.times[kind];

                diffInSeconds = absolute - value;

                times[kind] = value * m;

                diffInSeconds = diffInSeconds * Date.times[kind];

            end

            if (math.abs(t) >= 1) then

                times["t_"..kind] = t;

            else

                times["t_"..kind] = 0;

            end

        end

        times["t_seconds"] = constant;

        return times;

    end



    function self.odiff(date2)

        local diffInSeconds = date2.timestamp+self.timestamp;

        local t1 = os.date("*t", date2.timestamp);

        local t2 = os.date("*t", self.timestamp);

        local t3 = {}

        for k, v in pairs(t1) do

            if Date.def[k] then

                if ( type(v) == 'number' ) then

                    t3[k] = t2[k] - v;

                end

            end

        end

        return t3;

    end



    function self.format(stringFormat)

        stringFormat = stringFormat or "c"

        return os.date(stringFormat:gsub("([\\]?)(%w)", function(a,b)

            if a == "\\" then

                return a..b

            else

                return a.."%"..b

            end

        end), self.timestamp)

    end



    function self.isLeapYear()

        local year = tonumber(self.format("Y"));

        return year%4==0 and (year%100~=0 or year%400==0);

    end



    return self

end



a = Date.new("1990-01-30");

b = Date.new("1990-01-31");

c = Date.new("29-01-90", "d-m-y");

print(a.format("Y-m-d"), b.format("Y-m-d"), c.format("Y-m-d"))

print(a.diff(b).getTotal('days'), a.diff(c).getTotal('days'))



table.foreach(a.odiff(b), print)

table.foreach(a.odiff(c), print)



a = Date.new("August 13, 90")

print(a.format("Y-m-d"))

**webultra** · 09-08-2014, 12:17 AM

BTW, you should be using a lua library instead of trying to reinvent the wheel but maybe as you, i also like to write my own code. Maybe you just needed to write a function to guess the format and then return a desired format to then calculate the diff between to dates with another library.

Another note: I'm out of practice with lua so if you see any typo or something like writing 3 times the self.timestamp = os.time(tableTime) instead of 1 at the end of the "IF statement" or wrote 3 "IF" instead of 1, etc...don't be hard with me :P

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New DateDiff function

New DateDiff function

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