Calculating Age

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open System

let getAge (d : DateTime) =
        let d' = DateTime.Now
        match d' > d with
        | true ->
            let months = 12 * (d'.Year - d.Year) + (d'.Month - d.Month)
 
            match d'.Day < d.Day with
            | true -> let days = DateTime.DaysInMonth(d.Year, d.Month) - d.Day + d'.Day
                      let years = (months - 1) / 12
                      let months' = (months - 1) - years * 12
                      (years, months', days)
            | false -> let days = d'.Day - d.Day
                       let years = months / 12
                       let months' = months - years * 12
                       (years, months', days)
 
        | false -> (0,0,0)

// Example
let birthDate = DateTime.Parse("2/8/1995")
let y, m, d = getAge birthDate
printfn "Age: %d years, %d months and %d days." y m d

// Output
// Age: 15 years, 5 months and 6 days. 

namespace System

val getAge : d:DateTime -> int * int * int

Full name: Script.getAge

val d : DateTime

Multiple items
type DateTime =
  struct
    new : ticks:int64 -> DateTime + 10 overloads
    member Add : value:TimeSpan -> DateTime
    member AddDays : value:float -> DateTime
    member AddHours : value:float -> DateTime
    member AddMilliseconds : value:float -> DateTime
    member AddMinutes : value:float -> DateTime
    member AddMonths : months:int -> DateTime
    member AddSeconds : value:float -> DateTime
    member AddTicks : value:int64 -> DateTime
    member AddYears : value:int -> DateTime
    ...
  end

Full name: System.DateTime

--------------------
DateTime()
   (+0 other overloads)
DateTime(ticks: int64) : unit
   (+0 other overloads)
DateTime(ticks: int64, kind: DateTimeKind) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, calendar: Globalization.Calendar) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, kind: DateTimeKind) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, calendar: Globalization.Calendar) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, millisecond: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, millisecond: int, kind: DateTimeKind) : unit
   (+0 other overloads)

val d' : DateTime

property DateTime.Now: DateTime

val months : int

property DateTime.Year: int

property DateTime.Month: int

property DateTime.Day: int

val days : int

DateTime.DaysInMonth(year: int, month: int) : int

val years : int

val months' : int

val birthDate : DateTime

Full name: Script.birthDate

DateTime.Parse(s: string) : DateTime
DateTime.Parse(s: string, provider: IFormatProvider) : DateTime
DateTime.Parse(s: string, provider: IFormatProvider, styles: Globalization.DateTimeStyles) : DateTime

val y : int

Full name: Script.y

val m : int

Full name: Script.m

val d : int

Full name: Script.d

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn