Problem with simple "IF" statement cause

[brett s]

I have a fatal error occurring in a simple "IF" statement in a report every time I run the report. The IF statement is for a calculated variable that takes this form:

MyCalc = if(calc1""calc2,initialvalue,MyCalc)

Which is to say that I want the MyCalc calculated variable to retain its current setting until calc1 is not equal to calc2 when it will be assigned an initial value.

The problem I have is that when I run the report A5 immediately terminates - no error message of warning of any kind, it just immediately terminates.

I have tried rearranging the IF statement but with no effect, the same problem recurs.

Is there a work-around available? I just want the calculated variable to retain its current setting until calc1 is equal to calc2. A simple enough requirement but seemingly impossible for me to implement.

(I have attached a screen dump of the detail if anyone wants to see more).

[JohnZaleski]

RE: Problem with simple

try creating another calculated field "calc3" equalt to whatever and then
MyCalc = if(calc1""calc2,initialvalue,calc3)

[brett s]

RE: Problem with simple

OK, thanks. I will try this out.

[Tom Cone Jr]

RE: Problem with simple

brett, if that doesn't work try reframing the expression without using any other calc fields to do so.

-- t

[brett s]

RE: Problem with simple

Thanks for the suggestion, Tom, but I don't think that will be possible. This is a really complex report I am converting from a ten year old Alpha Four DOS-based application. The original report could not be done in A4 so I had previously done it using a third party report writer, R&R. So far I am not having a lot of joy re-doing the report in A5 either. I have just decided to scrap three day's work on the report and start again and see how I get on this time.

[G Gabriel]

RE: Problem with simple

Brett:
There is nothing simple about your "If" statment! I hate to break the news to you, but you simply can not make the left side of the equation dependant on the right side of the equation which is dependant on the left side of the equation...!!! you see where a5 is having trouble! you threw alpha in a never-ending "vicious cycle" hence the fatal error. Matter of fact, this is not just alpha's problem: if you try to do that in Excel or Lotus 123 you will not even be able to enter the function in the first place!
I read John's suggestion, but I have a feeling it will give you the same erro since you are doing the same "inter-dependency" except this time with a third party!
So now what? you could do it with a "simple" xbasic:
if calc1""calc2
mycalc=initialvalue
end if

[brett s]

RE: Problem with simple

Yes, I see your point. I guess I am used to working with another product that *does* allow this syntax whereas A5 appears to accept it and then fall over with an internal error.

What I want to do is have a calculated field in a report with the following type of logic:

Dim A as C
IF A = "ABC" then
A = A + "XYZ"
END IF

That is to say, no ELSE statement. But the A5 IF statement syntax in the reporting module does not allow either of the following 2 options that would give me this equivalent result:

A = IF(A="ABC",A+"XYZ",A) i.e. leave the value of A untouched if it is equal to "ABC"

or

A = IF(A="ABC",A+"XYZ") i.e. leave out the ELSE branch

So I appear to be stuck and with no easy work around. Am I missing something? Surely there must be syntax in the A5 reporting module that would allow me to achieve this result.

[G Gabriel]

RE: Problem with simple

Brett:
No, you are not stuck. The two approaches appear identical, like twin isiters, but in fact they are totally different:
if you enter an equation like this: A = A + "XYZ" in a function (functions are equations, xbasic is your gofer!, functions work according to the laws of math, xbasic will do whatever you tell it do! it's a subtle difference and that seems to cause your frustration).

Take Look at this equation for a second and think:
A=A+"XYZ" !!

Since when 1 equals 1+2 ?
Go tell that to the marines! If that's possible you my friend have made the discovery of the melinium and you could be the richest man ever lived because you could make a dollar equals a dollar and then some! Only Jesus broke this laws when he broke the bread and mutliplied it, but I do not know if Brett could do it!

But with xbasic, your gofer, you tell xbasic: go change A from A to A+"XYZ". I I captain! no problem. But when you put that in equation, alpha is spinning arounfd and around trying to figure out how the heck 1=1+2!
What you had was an equation from out of this world! does not obey the laws of math! I simply suggested that you change it from an equation (stiff with no sense of humor)to your obdient servant xbasic! When you tell xbasic A=A+"XYZ" you are not telling it that A does equal A+"XYZ" you are telling it GO CHANGE A to A+"XYZ". Can you see the subtle difference!

Gabe

[brett s]

RE: Problem with simple

Here the "=" sign is an operator as commonly used in computer langages: the statement A = A + 1 is an instruction to the computer to take the contents of the variable A, add 1 to it and stick the result back in A. It's not a mathematical equation. But I guess I am stuck with some idiosynchrasies (or problems) that I will have to put up with, I can't see the problem in A5 being fixed so I will have to find a way around it. I was hoping not to have to resort to Xbasic to do such a simple thing, but I may have no other easier option.
Thanks for your help, Gabriel.

[Tom Cone Jr]

RE: Problem with simple

Brett,

If MyCalc was a table field your approach would be fine.

But...

as Gabe correctly notes...

you're using the calc field MyCalc to define the calc field MyCalc. This isn't permitted in any of the coding languages I've ever used.

An easy fix is to compute the alternative value ahead of time, store it in a variable, and use the variable to supply the value to the calc.

if( A "" B , New Value, Alternative Value )

A further caution: if this a numeric comparison beware of rounding differences that could cause inequality when you don't want it.

-- t

[brett s]

RE: Problem with simple

Our experiences must differ because I have found the reverse to me true. For example, defining MyCalc as:

if( A "" B , New Value, MyCalc )

... is valid syntax. It works in the DBF report writers I have used, including R&R Report Writer. But there is a trick entailed. The definition must be entered initially as:

if( A "" B , New Value, Alternative Value ) ...A

This definition must be saved, only then can it be altered to:

if( A "" B , New Value, MyCalc ) ...B

That is to say the entry for the definition for MyCalc must be present before MyCalc can be used as a parameter in it's own definition. Which sort of makes sense.

You should try this little trick in some of the "coding languages" you mention.

Now, lets try this same trick with the A5 report writer.

Entering an initial definition for MyCalc into A5 as in B above gives a syntax error. But when entered as per A, saved and then modified to B, A5 accepts it as valid syntax!!!

And now when I try and run my report containing this definition for MyCalc, A5 crashes in flames. Clearly it shouldn't do so but it does.

So where to now? IMHO syntax B is correct and should be accepted by A5 and produce the correct result. The correct result is as per the following code:

if A""B then
MyCalc = New Value
end if

That is to say if A is equal to B the value of MyCalc retains its present value.

This is a perfectly legitimate logical outcome that is not currently supported by the A5 report writer using this form of the IF statement. In my view it is a serious omission that should be corrected.

I am quite prepared to make a submission to the good folk at Alpha Software to this effect if I felt that I would be listened to.

Comments welcome.

[Tom Cone Jr]

RE: Problem with simple

Yes, our experiences differ. Good luck with your project.

-- t