B4J Library [B4X] Eval (expressions evaluator)

Sub AppStart (Args() As String)
   Dim e As B4XEval
   e.Initialize(Me, "Eval")
   Log(e.Eval("1 + Min(2, Max(-4, 1), 6)"))
   Log(e.Eval("-(2+5)*(7-3) + Sin(15 + 15) + Cos(30)"))
   Log("Error? " & e.Error)
   Log(e.Eval("-(2+5)*-(7-3)"))
   Log(e.Eval("-((-7-3))"))
   Log(1.321/-2/3.123 + (2 * 2 + 3) + 4)
   Log(e.Eval("1.321/-2/3.123 + (2 * 2 + 3) + 4"))
End Sub

'custom functions implementation
Sub Eval_Function (Name As String, Values As List) As Double
   Select Name 'it will be lower case
     Case "min"
       Dim d As Double = Values.Get(0)
       For Each n As Double In Values
         If n < d Then d = n
       Next
       Return d
     Case "max"
       Dim d As Double = Values.Get(0)
       For Each n As Double In Values
         If n > d Then d = n
       Next
       Return d
     Case "sin"
       Return SinD(Values.Get(0))
     Case Else
       Log("Invalid function: " & Name)
       Dim e As B4XEval = Sender
       e.Error = True
       Return 0
   End Select
End Sub