Hi all, While writing contracts for classes in racket/gui, I noticed that the implementations of text% and pasteboard% do not act as behavioral subtypes of editor<%>, which both classes implement.
In particular, consider the do-copy method from editor<%>. Its contract looks like this: (send an-editor do-copy) → void? http://pre.racket-lang.org/docs/html/gui/editor___.html?q=do-copy#(meth._(((lib._mred/main..rkt)._editor~3c~25~3e)._do-copy)) However, the implementations have the following contracts: (send a-text do-copy start end time extend?) → void? http://pre.racket-lang.org/docs/html/gui/text_.html?q=do-copy#(meth._(((lib._mred/main..rkt)._text~25)._do-copy)) and (send a-pasteboard do-copy time extend?) → void? http://pre.racket-lang.org/docs/html/gui/pasteboard_.html?q=do-copy#(meth._(((lib._mred/main..rkt)._pasteboard~25)._do-copy)) That is, do-copy in editor<%> has no mandatory arguments, do-copy in text% has four mandatory arguments, and do-copy in pasteboard% has two mandatory arguments. Thus, the do-copy methods in text% and pasteboard% do not implement the editor<%> interface (in the behavioral subtyping sense) nor do they implement a common interface despite claiming to. There are several other examples of this issue in the same classes. (see do-paste, paste-x-selection, etc.) Is there a design rationale for this? Is this method not meant to implement a common interface? Cheers, Asumu _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev