[plt-scheme] list-box's maximum size of string?

Thanks  for the explanation and the code.


On Tue, Nov 18, 2008 at 5:58 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> At Tue, 18 Nov 2008 16:15:27 +0530, Veer wrote:
>>  When i use following code:
>>
>>    (send msg-lst set lines)
>>
>>  where msg-lst is a instance of list-box%  and lines is a (listof strings)
>>  it complains with following error/message :
>>
>>  "set in list-box%: expected argument of type <list of strings (up to
>> 200 characters)>; ...  .."
>>
>>  Some of my lines are indeed more than 200 characters long.
>>
>>  So how do i overcome this restriction
>
> You can use `hierarchical-list%' from `mrlib/hierlist'.
>
> Unfortunately, the methods on `hierarchical-list%' are different. Also,
> it can be tricky to get a `hiearchical-list%' to look like a
> `list-box%', if that is a concern. Some example code is below.
>
>>  also , out of curiosity why such
>>  restriction is needed?
>
> It's a result of using old GUI toolbox layers, such as an Xt-based
> widget layer under X11 and Carbon APIs under Mac OS X, which have
> limits in various places. This particular limit may not have to do with
> list boxes; at some point, we chose a consistent 200-character limit
> for all GUI labels.
>
> Matthew
>
> ----------------------------------------------------------------------
> A simple list box:
> ----------------------------------------------------------------------
> #lang scheme/gui
>
> (define f (new frame% [label "List"]
>               [width 200]
>               [height 200]))
>
> (define l (new list-box%
>               [label #f]
>               [choices '()]
>               [parent f]))
>
> (send l set (for/list ([in (in-range 100)])
>              (make-string 200 #\z)))
>
> (send f show #t)
>
> -------------------------------------------------------------------------
> hierlist simulating a list box, but without the label-width limit:
> ----------------------------------------------------------------------
> #lang scheme/gui
> (require mrlib/hierlist)
>
> (define f (new frame% [label "List"]
>               [width 200]
>               [height 200]))
>
> (define l (new hierarchical-list%
>               [label #f]
>               [parent f]
>               [style '(control-border no-hscroll)]))
> (send l set-no-sublists #t)
> (send l horiz-margin 2)
> (send l vert-margin 2)
> (send l horizontal-inset 0)
> (send l vertical-inset 0)
>
> (define items (for/list ([i (in-range 100)])
>                (make-string 201 #\z)))
>
> (for ([i (in-list items)])
>  (send (send (send l new-item) get-editor) insert i))
>
> (send f show #t)
>
>