Placement of widgets

[Stéphane Goujet]

Hello,

  as far as I could see, there is no such thing in GNUstep (or Cocoa) 
as, for example, Tcl/Tk geometry manager, which allows the programmer to 
place widgets relatively to each others,  set rules for padding, 
expanding, resizing, etc. and apply them, etc.

  Is there a way to achieve such a result, programmatically, with 
GNUstep ?
  Is there a library or toolkit that would perform the same kind of 
effect ?

Goodbye,
         Stéphane Goujet.