Field rule limitations

[Chris Zito]

I am trying to revamp a table that performs a lot of calculations. When I started this project and was totally in the dark, I set this up so that the the fields were set up as user entered fields and I used the send_keys command to tab thru the fields which would populate based on conditional default values I had defined. Now I am trying to move all these rules into calculated fields (changing the field designation itself) and am having success up to this point: several of the conditions are lengthy and when I combine all the different elements into a case() argument, not all of the command fits into the space. I did a look up and discovered that there is a character limitation for these field rules. Someone made reference about making a function of my calculation and placing the function in the field rule. How is this accomplished? Any suggestions will be greatly appreciated.

[Melvin Davidson]

RE: Field rule limitations

Chris,

In Alpha Five, you can create a user function in the code tab section.

Just click the New button, and select Function from the drop down. Then fill in the required info (function name, return type and optional input parameters). FInally, complete the function in the script editor. After that, you can reference the function name anywhere, providing you are using the same db.

[Stan Mathews]

RE: Field rule limitations

For a little fuller explanation, convert your case statement to a case command structure

select
case

case


end select

then convert it to a function as mentioned like

FUNCTION test AS N (parameter1,parameter2,parameter...)
test = 0 'set default return value
select
    case cond1 = .t.
      test = result of some computation
    case cond2 = .t.
      test = result of some other computation
    case cond3
      test = result of yet another computation
end select
END FUNCTION

Then the usage in your field rule would be

test(value1,value2,value...)

[Stan Mathews]

RE: Field rule limitations

For a little fuller explanation, convert your case statement to a case command structure

select
case

case


end select

then convert it to a function as mentioned like

FUNCTION test AS N (parameter1,parameter2,parameter...)
test = 0 'set default return value
select
case cond1 = .t.
test = result of some computation
case cond2 = .t.
test = result of some other computation
case cond3
test = result of yet another computation
end select
END FUNCTION

Then the usage in your field rule would be

test(value1,value2,value...)

[Chris Zito]

RE: Field rule limitations

Thanx for the replies. I will give these suggestions a go and reply with the outcome.

[Chris Zito]

RE: Field rule limitations

Stan,

Would you be able to clarify certain elements of:Then the usage in your field rule would be

test(value1,value2,value...)? Specifically, is this the exact wording? By saying value1, does the program pick the first true value?

[Melvin Davidson]

RE: Field rule limitations

Chris,

You would be well advised to refer to the
Xbasic Referernce Manual and the section that
describes Function (Page 80)

[Stan Mathews]

RE: Field rule limitations

suppose your computation involves three field values

fielda
fieldb
fieldc

and the case conditions

case a " b

case b " c

case c " a

The function, specifically without the computation results, would be

FUNCTION test AS N (a as N,b as N,c as N)
test = 0 'set default return value
select
case a " b
test = result of some computation
case b " c
test = result of some other computation
case c " a
test = result of yet another computation
end select
END FUNCTION


and the usage would be

test(fielda,fieldb,fieldc)

[Edward Larrabee]

RE: Field rule limitations

The latest version of the reference documentation for functions starts at Overview: Functions and Expressions.