OpItemMethod

Applies to:Fast Math Parser
Class:uCalc.Callback
Returns the function or operator Item of the current expression part
Syntax
OpItem()
Remarks
If several functions and/or operators are mapped to the same callback function, you can use this to let you determine which one is currently being called, based on properties you can check.
Example 1: Determining properties of an expression part
Sub OpItemTestCB(ByVal ExprPartPtr As IntPtr)
   Dim ExprPart As New uCalc.Callback(ExprPartPtr)
   Console.WriteLine("Name: " + ExprPart.OpItem().Name())
   Console.WriteLine("Data type: " + ExprPart.OpItem().GetDataType().Name())
   Console.WriteLine("Param count: " + ExprPart.OpItem().ElementCount())
   Console.WriteLine("Is operator? " + ExprPart.OpItem().IsProperty(ItemIsEnum.Operator_))
End Sub

Sub HandleTest()
   uc.DefineFunction("AAA() As Double", uc.PinAddr(AddressOf OpItemTestCB))
   uc.DefineFunction("BBB(x, y, z) As String", uc.PinAddr(AddressOf OpItemTestCB))
   uc.DefineOperator("{x} CCC {y} As Int32", 0, GroupingEnum.GroupLeftToRight, uc.PinAddr(AddressOf OpItemTestCB)): ' 0 should work
   uc.EvalStr("AAA()")
   ' Output
   ' Name: aaa
   ' Data type: double
   ' Param count: 0
   ' Is Operator_? 0

   uc.EvalStr("BBB(9, 8, 7)")
   ' Output
   ' Name: bbb
   ' Data type: string
   ' Param count: 3
   ' Is Operator_? 0

   uc.EvalStr("5 CCC 4")
   ' Output
   ' Name: ccc
   ' Data type: Int32
   ' Param count: 2
   ' Is Operator_? 1
End Sub

          
DLL import code
<DllImport(uCalcDLL, CharSet:=CharSet.Ansi, CallingConvention:=CallingConvention.Cdecl, EntryPoint:="OpItem")> _

Private Function OpItem__(ByVal ExprPartHandle As IntPtr) As IntPtr
End Function
            
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