[Gambas-user] Probable bug with "_unknown" method when used for properties

[Benoît Minisini]

> Benoit,
> 
>    Here is more detail on the problem... What I'm attempting to do is
> read/write CISAM files from Gambas3.  I am using the external VBISAM
> library "libvbisam.so".  I have a VBISAM class and a driver program.  Here
> is the VBISAM Class:
> 
> ---------------------------------------------Begin
> VBISAM-------------------------------------
> Class VBISAM
> 
> Const ISFIRST As Integer = 0
> Const ISLAST As Integer = 1
> Const ISNEXT As Integer = 2
> Const ISPREV As Integer = 3
> Const ISCURR As Integer = 4
> Const ISEQUAL As Integer = 5
> Const ISGREAT As Integer = 6
> Const ISGTEQ As Integer = 7
> 
> Const ISLOCK As Integer = &H100&
> Const ISSKIPLOCK As Integer = &H200&
> Const ISWAIT As Integer = &H400&
> Const ISLCKW As Integer = &H500&
> Const ISKEEPLOCK As Integer = &H800&
> 
> Const ISAUTOLOCK As Integer = &H200&
> Const ISMANULOCK As Integer = &H400&
> Const ISEXCLLOCK As Integer = &H800&
> 
> Const ISINPUT As Integer = 0
> Const ISOUTPUT As Integer = 1
> Const ISINOUT As Integer = 2
> Const ISTRANS As Integer = 4
> Const ISNOLOG As Integer = 8
> 
> Const ISVARLEN As Integer = &H10&
> Const ISFIXLEN As Integer = 0
> 
> Extern isopen(FNAME As String, MODE As Integer) As Integer In "libvbisam"
> Extern isread(FD As Integer, BUFF As Pointer, MODE As Integer) As Integer
> In "libvbisam"
> Extern isclose(FD As Integer) As Integer In "libvbisam"
> 
> Public RecLen As Integer = 768
> Private FD As Integer
> Public ReturnCode As Integer
> Private BUFF As Pointer = Alloc(RecLen)
> Public DataRecord As String
> Private Dictionary As Collection
> 
> Private Sub ReadDict(FName As String)
>     Dim items As New String[30]
>     Dim DictIn As File
>     Dim TextLine As String
>     Dim i As String
>     Dim x As Integer
>     Dim Dict As DictEntry
> 
>   DictIn = Open FNAME & ".dic" For Read
>   ' Loop through each line until the end of file.
>   ' Eof() returns true at the end of the file.
> 
>   Dictionary = New Collection
> 
>   While Not Eof(DictIn)
>   Line Input #DictIn, TextLine
>     ' Split each line into fields
>     ' Note that we set the " char as an escape char
> 
>     items = Split(TextLine, ",", "\"")
> 
>     Dict = New DictEntry
>     items[3] = Replace$(items[3], "-", "_")
>     Dict.DataName = items[3]
>     Dict.Pos = items[4] + 1
>     Dict.Len = items[5]
>     Dict.Type = items[6]
>     Dict.Occurs = items[8]
>     Dict.Edit = items[12]
>     Dict.SerialNo = items[19]
>     Dictionary[items[3]] = Dict
> 
>  Wend
>  Close #DictIn
> End
> 
> Public Sub _new(FNAME As String, Optional MODE As Integer = ISINPUT +
> ISMANULOCK)
>   FD = isopen(FNAME, MODE)
>   ReadDict(FNAME)
> End
> 
> Public Sub close()
>   Dim ReturnCode As Integer
>   ReturnCode = isclose(FD)
>   Free(BUFF)
> End
> 
> Public Sub first() As Integer
>   Dim ch As Byte
>   Dim tmp As Pointer = BUFF
>   Dim I As Integer
>   Dim BuffStream As Stream
>   ReturnCode = isread(FD, BUFF, 0)
>   If ReturnCode < 0 Then
>      Return ReturnCode
>   Endif
>   BuffStream = Memory BUFF For Write
>   DataRecord = Read #BuffStream As String
>   Return ReturnCode
> End
> 
> Public Sub _next()
>   Dim ch As Byte
>   Dim tmp As Pointer = BUFF
>   Dim I As Integer
>   Dim BuffStream As Stream
>   BuffStream = Memory BUFF For Write
>   ReturnCode = isread(FD, BUFF, ISNEXT)
>   If ReturnCode < 0 Then Enum.Stop
>   DataRecord = Read #BuffStream As String
>   Return
> End
> 
> Public Function _unknown(...) As Variant
>   Dim Params As Integer = Param.Count
>   Dim D As DictEntry = Dictionary[Upper$(Param.Name)]
>   Dim Value As Variant
>   If Param.Property
>     If Params = 0 Then
>       Return Mid$(DataRecord, D.Pos, D.Len)
>     Else
>       Value = Param[0]
>       Mid$(DataRecord, D.Pos, D.Len) = Value
>     Endif
>   Endif
> End
> 
> -----------------------------------------------End
> VBISAM-------------------------------------
> 
> And here is the driver:
> ----------------------------------------------Begin
> MMain---------------------------------------
> ' Gambas module file
> 
> Public Sub Main()
> Dim CUSTOMER As VBISAM
> Dim RESULT As Integer
> Dim CustCount As Integer = 0
> Dim Branch As String
> CUSTOMER = New VBISAM("/data/CUSTFILE")
> RESULT = CUSTOMER.first()
> For Each CUSTOMER
>    Branch = CUSTOMER.Branch
>    If CUSTOMER.Branch = "000" Then Goto ReadNext
>    Print CUSTOMER.Key, CUSTOMER.Name, CUSTOMER.City, CUSTOMER.State,
> CUSTOMER.Zip_Code
>    CustCount += 1
> ReadNext:
> Next
> CUSTOMER.close()
> Print "Total Customers: " & CustCount
> End
> -------------------------------------------End
> MMain----------------------------------------
> 
> The error message I get in line 12 of MMain is:
> Type mismatch: Wanted Number, Date, or String, got Function instead in
> MMain:12.
> 
> 
> Without the "If CUSTOMER" statement, everything is fine (i.e., I can use a
> property as as string when I print or do other opeations).  However, the
> "IF" statrement (line 12) doesn't like the unknown property at all!  I set
> a breakpoint in the _unknown method of VBISAM and it gets there when using
> the unknown properties in print statements (or other expressions), but
> does not when using it in a conditional.
> 
> Hope that helps,
> 
> gwalborn

Can you provide a project with the previous code so that I can debug?

-- 
Benoît Minisini