Days Between To Dates

rbuser

Delphi has a DaysBetween function where I can get the number of days between
two dates. Is there a way to do the same thing with rap.

Thanks,
Richard Gostin

nicocizik

Hi Richard,

Although RAP does not support the DaysBetween routine, it should be fairly
simple to calculate the days between two TDateTime types using the Integer
representation of each type. Subtracting one date from the other in integer
form will give you the difference in days.

Also, if you would like to implement a pass thru function, you can manually
add this functionality to RAP.

--------------------------------------------------
Article: Extending RAP
---------------------------------------------------

There are two very simple and powerful techniques to extend the capabilities
of RAP infinitely. These are summarized below and covered in more detail in
the RAP.hlp online help. Demos and tutorials are installed to
RBuilder\Demos\RAP. The tutorial text is located in RAP.hlp.


1. RAP Pass-Through Functions

These are functions that appear in the Language tab of RAP's Code Toolbox.
These functions are written in Delphi and can be called from RAP. RAP's
pass-through function architecture enable's developers to add new built-in
functions to RAP's code toolbox.

2. Extend RAP's RTTI

RAP's Run-time Type information defines what classes and properties can be
accessed via RAP. By default the published properties of any class that is
registered with Delphi's RegisterClass procedure is recognized by RAP. In
addition many of the public properties and methods of ReportBuilder classes
are exposed.


--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Richard,

Here is the RAP Pass-Thru function that we use:

Add the following to the interface section of the unit:

type
TraReturnDaysBetweenDates = class(TraSystemFunction)
public
class function Category: string; override;
procedure ExecuteFunction(aParams: TraParamList); override;
class function GetSignature: string; override;
class function HasParams: Boolean; override;
class function IsFunction: Boolean; override;
end;

Add the following the implemenation section of the unit:

{
************************** TraReturnDaysBetweenDates
***************************
}
class function TraReturnDaysBetweenDates.Category: string;
begin
Result:= 'DateTime'
end;

procedure TraReturnDaysBetweenDates.ExecuteFunction(aParams: TraParamList);
var
iResult: Integer;
Date1: TDateTime;
Date2: TDateTime;
begin
GetParamValue(0, Date1);
GetParamValue(1, Date2);

iResult:= ReturnDaysBetweenDates(Date1,Date2);

{ The return value is the last value in the zero based parameter list }
SetParamValue(2, iResult);
end;

class function TraReturnDaysBetweenDates.GetSignature: string;
begin
result := 'function ReturnDaysBetweenDates(Date1, Date2: TDateTime):
Integer;';
end;

class function TraReturnDaysBetweenDates.HasParams: Boolean;
begin
Result:= True;
end;

class function TraReturnDaysBetweenDates.IsFunction: Boolean;
begin
Result:= True;
end;

Add the following to the initialization section of the unit:

raRegisterFunction('ReturnDaysBetweenDates', TraReturnDaysBetweenDates);

I hope this helps.
Scott

rbuser

Oops...

You will have to make the following change in the
TraReturnDaysBetweenDates.ExecuteFunction procedure:

CHANGE:

iResult:= ReturnDaysBetweenDates(Date1,Date2);

TO

iResult:= DaysBetween(Date1,Date2);

Scott