First I have to get some more logical errors out of my code. The below is
cleaned up.
C_BOOLEAN($0;$setDoesExist)
C_TEXT($1;$setName)
C_BOOLEAN($testInSet)
C_LONGINT($numInSet)
$setName:=$1
$numInSet:=Records in set($setName)
If ($numInSet>0)
$setDoesExist:=True
Else
// two possibilities
// 1. set does not exist
// 2. set exists but has no records
// logic: The documentation says: // ADD TO SET ( {aTable ;} set ) …
ADD TO SET adds the current record of aTable to set. The set must already
exist; if it does not, an error occurs.
// if the set does not exist, I will get an error.
// if it does exist then I will NOT get an error but it is safe
because I will not have changed the state of anything since adding zero records
to an existing set does nothing.
fErrorHappened:=False // this is a process variable that is created at
startup
ON ERR CALL("ErrorIgnore") // ErrorIgnore is a method that sets
fErrorHappened to true
ADD TO SET($setName) // if the set does not exist, this will throw an
error. This particular "Set" command is sensitive as to whether the set exists
ON ERR CALL("")
If (fErrorHappened)
$setDoesExist:=False
Else
$setDoesExist:=True
End if
End if
$0:=$setDoesExist
> On Jul 17, 2017, at 1:07 AM, Julio Carneiro via 4D_Tech
> <4d_tech@lists.4d.com> wrote:
>
> Just out of curiosity, what happens if there is no current record to add to
> the set?
> - do you get an error, which might only indicate no record exists to add to
> an existing set?
> - nothing happens, even if set does not exist?
I am doing the testing in a simple interpreted environment. No server etc.
If there is an empty current selection then the code (interpreted) correctly
determines whether the set exists or does not exist.
If there is a multi-record current selection but the current record does not
exist than the code (interpreted) correctly determines whether the set exists
or does not exist.
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