How to use ?modifyCallback on hiCreateStringField() properly?

Hello,

For a string field of a form, I want to specify a callback function which gets triggered after each keystroke. I use the function hiCreateStringField() and I specify the ?modifyCallback to trigger the function I want (it performs a rexMatchp() on a list that has all cells in a given library and puts this list as the ?choices list in an other (cyclic) form field, thus the list gets updated dynamically, making it easier to locate a cell in a library).

Somehow it doesn't work properly since I get errors.

To start, this is working fine, and the callback function works properly (just to make clear that there is no error in the code of the callback function):

hiCreateStringField(
  ?name       'BcipFindCellsToBrowse
  ?prompt     "Cells to browse:"
  ?value      ""
  ?defValue   ""
  ?callback   "tempProc()"
  ?editable   t
  ?enabled    t
)

This is the tempProc():

procedure( tempProc()
  let( ( ( temp nil ) )
    BcipGuiForm~>BcipCellsToBrowse~>value = nil
    if( equal( BcipGuiForm~>BcipFindCellsToBrowse~>value "" )
    then
      BcipGuiForm~>BcipCellsToBrowse~>choices = BcipDefineCellnameList( BcipGuiForm~>BcipLibrariesToBrowse~>value )
    else
      foreach( item BcipDefineCellnameList( BcipGuiForm~>BcipLibrariesToBrowse~>value )
        when( rexMatchp( BcipGuiForm~>BcipFindCellsToBrowse~>value item )
          temp = cons( item temp )
        ) ;;; end of when
      ) ;;; end of foreach item
      BcipGuiForm~>BcipCellsToBrowse~>choices = reverse( temp )
    ) ;;; end of if
  ) ;;; end of let
) ;;; end of procedure tempProc

So, when typing in the springfield, after it loses focus it performs tempProc() and the ?choices list of BcipCellsToBrowse gets updated accordingly.

When I do the following:

hiCreateStringField(
  ?name             'BcipFindCellsToBrowse 
  ?prompt           "Cells to browse:"
  ?value            ""
  ?defValue         ""
  ?modifyCallback   "tempProc()"
  ?editable         t
  ?enabled          t
)

It generates errors.

After each keystroke, the procedure tempProc() gets executed (I know that since the ?choices list gets updated correctly) but the following error is reported in the CIW:

*Error* eval: not a function - 'BcipFindCellsToBrowse
*Error* car: Can't take car of atom - ERROR

I get the same error if I replace "tempProc()" with "printf(\"Help\")".

When I look at the documentation, the explanation for ?callback differs significantly from the ?modifyCallback explanation.

The ?modifyCallback passes three values to the callback function (s_filename, t_lastTextValue and g_sourceOfChange) and it expects to get back either t, nil or a value. This is where it is breaking in my code, I suppose. I have tried several things (like returning a "t" at the end of tempProc()) but none of them worked.

So I would like to know:

• the ?modifyCallback passes three values, how do I access them (for an other form I really want to know what the g_sourceOfChange is)
• How do I return something to satisfy the ?modifyCallback of the field?
• And what should I return (simply "t")?
• Is there a smarter method for what I want (something already build into Cadence/SKILL)?

Any help is highly appreciated since I hate to distribute code that works but generates errors.

With kind regards,

Sjoerd

ps:

This is what BcipDefineCellnameList() does:

procedure( BcipDefineCellnameList( refLib "l" )
  let( ( ( lib nil )
    ( libDbId nil )
    ( cell nil )
    ( cellNameList nil ) )

    foreach( lib refLib
      libDbId = ddGetObj( lib )
      foreach( cell libDbId~>cells
        if( member( cell~>name cellNameList )
        then
          cellNameList = cellNameList
        else
          cellNameList = append( cellNameList list( cell~>name ) )
        ) ;;; end if
      ) ;;; end foreach cell
    ) ;;; end foreach lib

    cellNameList = ( sort cellNameList nil )

  ) ;;; end let
) ;;; end procedure BcipDefineCellnameList

refLib is a list of strings, each string is the name of a library.