View member feedback to this tip.
This code can be used to validate a Notes formula before using it in an Evaluate() statement or in a call to db.Search(). It will also tell you the offset of any error. I use it in a Web interface to create customized reports to mimic Domino Designer's "Check formula" functionality. It uses functions in the Notes DLL, as documented in the Lotus C API, example code support Win32 (look here for help on using the same code on another platform).
Here's an example:
Dim sFormula as String
sFormula = {SELECT FORM =
"MyForm" & @IsAvailable(Status_T)}
iRC =
CheckSelectionFormulaValid
(sFormula)
if iRC(0) = NO_ERROR Then
Print "Formula is valid!"
Else
Print "Formula error: " &
GetAPIError(iRC(0))
Print "Error starts at character: "
& Cstr(iRC(1)) & " and ends at
character: " & Cstr(iRC(2))
End If
Removing the "@" from the
@IsAvailable keyword should
give you those results:
Formula error: @Function or
operator expected, or @Function
does not require an argument.
Error starts at character 47 and ends
at character 47, which is the last parentheses.
Const NULLHANDLE = 0
Const NO_ERROR = 0
Const ERR_FORMULA_COMPILATION
= &h500 + 1
Declare Function NSFFormulaCompile
Lib "nnotes.dll" ( _
Byval FormulaName As Long, _
Byval FormulaNameLength As Integer, _
Byval FormulaText As Lmbcs String, _
Byval FormulaTextLength As Integer, _
rethFormula As Long, _
retFormulaLength As Integer, _
retCompileError As Integer, _
retCompileErrorLine As Integer, _
retCompileErrorColumn As Integer, _
retCompileErrorOffset As Integer, _
retCompileErrorLength As Integer _
) As Integer
Declare Sub OSMemFree Lib "nnotes.dll"
(Byval hHandle As Long)
Declare Function OSLoadString Lib
"nnotes.dll" ( _
Byval hmodule As Long, _
Byval status As Integer, _
Byval s As String, _
Byval slen As Integer _
) As Integer
' =============================
===============================
====================
' CheckSelectionFormulaValid -
This function uses the Lotus
C API to check the
syntax of a Notes formula.
'
' Return Value: Variant - A 3 elements
array containing:
' Index 0 - The compilation error code
or NO_ERROR (0) if valid
' Index 1 - The compilation error offset
in formula or NO_ERROR if valid
' Index 2 - The compilation error length
or NO_ERROR if valid
'
' Note: The compilation error code at
Index 0 can then be passed to GetAPIError
() to get more info about the error.
' =============================
==============================
=====================
Function CheckSelectionFormulaValid
(sFormula) As Variant
Dim iError As Integer
Dim hFormula As Long
Dim wFormulaLen As Integer
Dim iCompileError As Integer
Dim iCompileErrorLine As Integer
Dim iCompileErrorColumn As Integer
Dim iCompileErrorOffset As Integer
Dim iCompileErrorLength As Integer
Dim iArray(2) As Integer
iError = NSFFormulaCompile(0, 0, _
sFormula, _
Len(sFormula), _
hFormula, _
wFormulaLen, _
iCompileError, _
iCompileErrorLine, _
iCompileErrorColumn, _
iCompileErrorOffset, _
iCompileErrorLength)
If hFormula <> NULLHANDLE Then
Call OSMemFree(hFormula)
End If
If iError = ERR_FORMULA_COMPILATION
Then
iArray(0) = iCompileError
iArray(1) = iCompileErrorOffset
iArray(2) = iCompileErrorLength
CheckSelectionFormulaValid = iArray
Else
iArray(0) = NO_ERROR
iArray(1) = NO_ERROR
iArray(2) = NO_ERROR
CheckSelectionFormulaValid = iArray
End If
End Function
' ===============================
================================
=================
' GetAPIError - This function uses the
Lotus C API to return a Notes error's
text message.
'
' Return Value: String - The text associated
with the Notes API error code.
' ================================
=================================
===============
Function GetAPIError(iErrorCode As Integer)
As String
Dim iRetVal As Integer
Dim sError As String * 1024
sError = String(1024, 0)
iRetVal = OSLoadString(0&, iErrorCode,
sError, 1023)
If iRetval <> 0 Then
GetApiError = Left$(sError, iRetVal)
End If
End Function
MEMBER FEEDBACK TO THIS TIP
I think this is a great tip! The writer suggested using it prior to any Evaluate() call. I suggest using it to debug any @Formulas you are working with during routine development.
I created a simple form that I put in my utilities database and will use it all the time. The form has one field and one action button. Put something like this in the button:
Sub Click( Source As Button )
Dim ws As New NotesUIWorkspace
Dim uiDoc As NotesUIDocument
Set uiDoc = ws.CurrentDocument
iRC = CheckSelectionFormulaValid
( uiDoc.FieldGetText("testFormula" ) )
If iRC(0) = NO_ERROR Then
Msgbox "Formula is valid!"
Else
Print "Formula error: " &
GetAPIError(iRC(0))
Print "Error starts at character: " &
Cstr(iRC(1)) & " and ends at character: "
& Cstr(iRC(2))
Msgbox "Error starts at character: " &
Cstr(iRC(1)) & " and ends at character: "
& Cstr(iRC(2)), , _
"Formula error: " & GetAPIError(iRC(0))
End If
End Sub
You may also want to check out another tip, called Formula debugger. It's very similar to the tip listed above.
—Doug J.
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