[plt-scheme] a snip copy/paste puzzle

On Aug 8, 2009, at 4:52 PM, Robby Findler wrote:
> Do you get a stacktrace with the error message?

Not in the test frame.  But I do if I attempt to paste it into the  
Interactions REPL.  See below.

I'd been kind of wondering how I might figure out where a #f is being  
passed in place of an editor, without making changes to the private  
code -- tricky (or at least tedious) given all the callbacks involved,  
and didn't seem worth it for an uncertain payoff before inquiring here.

jmj

-------
set-editor method of editor-snip%: expects argument of type  
<interface:editor% instance>; given #f

  === context ===
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/editor- 
snip.ss:125:2: set-editor method in editor-snip%
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/snip.ss: 
1178:2: read method in editor-snip-class%
for-loop
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/editor.ss: 
600:2: read-snips-from-file method in editor%
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/editor.ss: 
1034:2: do-buffer-paste method in editor%
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/text.ss: 
2055:2: do-paste method in text%
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/text.ss: 
2087:2: core
/Applications/PLT Scheme v4.2/collects/framework/private/standard- 
menus.ss:382:4: edit-menu:paste-callback method in ...te/standard- 
menus.ss:179:2
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/keymap.ss: 
485:2: chain-handle-key-event method in keymap%
for-loop
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/keymap.ss: 
485:2: chain-handle-key-event method in keymap%
for-loop
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/keymap.ss: 
485:2: chain-handle-key-event method in keymap%
/Applications/PLT Scheme v4.2/collects/mred/private/wxme/keymap.ss: 
441:2: handle-key-event method in keymap%
/Applications/PLT Scheme v4.2/collects/mred/private/wxmenu.ss:56:23
/Applications/PLT Scheme v4.2/collects/scheme/private/more-scheme.ss: 
155:2: call-with-break-parameterization
...
-----------


>
>
>
> Robby
>
> On Sat, Aug 8, 2009 at 1:57 AM, Jordan Johnson<jmj at fellowhuman.com>  
> wrote:
>> Hi all,
>>
>> I've been working on a snip implementation (representing an annotated
>> expression) and am getting a mysterious error.  I'd be grateful for  
>> any help
>> the community can offer in solving the problem.
>>
>> The error:  Currently when I attempt to copy and paste my snip, I  
>> get the
>> error
>>
>>        set-editor method of editor-snip%: expects argument of type
>> <interface:editor% instance>; given #f
>>
>> ...and the editor-snip% in question is apparently not any of the  
>> snips I've
>> defined, which I've verified by overriding their set-editor  
>> method.  This
>> error is coming from somewhere deep in MrEd, and (after  
>> embarrassingly many
>> hours of reading internal code and probing/rewriting) I don't see  
>> the cause.
>>
>> Below is a version I've pared down to just what's necessary to see  
>> the
>> structure and exercise the bug.  To reproduce the error:  run it,  
>> evaluate
>> (test-w/text%), and attempt to copy and paste the editor-snip% you  
>> see in
>> the frame it created.
>>
>> Any observations?
>>
>> Thanks,
>> jmj
>>
>> ;;;;;;; code-desc-simplified.ss
>>
>> #lang scheme/gui
>>
>> (require framework embedded-gui)
>> (provide anno-snip%)
>>
>> ;;;;;;;;;; Snipclassery (for cut/paste) ;;;;;;;;;;;
>> ;; Design follows framework/private/comment-box.ss lines 23-31
>> (define anno-snipclass%
>>  (class decorated-editor-snipclass%
>>    (define/override (make-snip stream-in) (new anno-snip%))
>>    (define/override (read in)
>>      (let ([pb (new anno-pb%)])
>>        (let ([code-ed (send pb get-code-editor)]
>>              [anno-ed (send pb get-anno-editor)])
>>          (send code-ed read-from-file in 'start)
>>          (send anno-ed read-from-file in 'start))))
>>
>>    (super-new)))
>>
>> (define snipclass (make-object anno-snipclass%))
>> (send snipclass set-version 1)
>> (send snipclass set-classname "code-desc-snip.ss")
>> (send (get-the-snip-class-list) add snipclass)
>>
>>
>> ;;;; Snip representing an annotated chunk of code.
>> (define anno-snip%
>>  (class decorated-editor-snip%
>>
>>    (define/override (make-editor) (new anno-pb%))
>>    (define/override (make-snip) (new anno-snip%))
>>
>>    ;; copy/paste:
>>    (inherit get-editor)
>>    (define/override (write stream-out)
>>      (let ([pb (get-editor)])
>>        (let ([code (send pb get-code-editor)]
>>              [anno (send pb get-anno-editor)])
>>          (send code write-to-file stream-out)
>>          (send anno write-to-file stream-out))))
>>
>>    (define/override (copy) ;; -> anno-snip%
>>      ;; return a copy of this snip
>>      (let ([s (new anno-snip%)])
>>        (send s set-editor (send (get-editor) copy-self))
>>        s))
>>
>>    (super-new)
>>    ))
>>
>> (define anno-pb%
>>  (let ()
>>    (define (find-owner-snip ed) ;; editor<%> -> (union #f editor- 
>> snip%)
>>      (let ([admin (send ed get-admin)])
>>        (and admin
>>             (admin . is-a? . editor-snip-editor-admin<%>)
>>             (send admin get-snip))))
>>    (define scheme+copy-self%    ;; class for the code editor
>>      (class scheme:text%        ;; (from framework/private/comment- 
>> box.ss)
>>        (inherit copy-self-to)
>>        (init-field [kind 'default])
>>        (define/override (copy-self)
>>          (let ([ed (new scheme+copy-self%)])
>>            (copy-self-to ed)
>>            ed))
>>        (super-new)
>>        (inherit set-max-undo-history)
>>        (set-max-undo-history 'forever)))
>>    (class aligned-pasteboard%
>>      (super-new)
>>
>>      ;;;;;;; Component editors:
>>      ;; code-editor and anno-editor are the two text%s that contain  
>> the
>>      ;; code and annotation, respectively.
>>      ;; -> (union #f text%)
>>      (define/public (get-code-editor) code-editor)
>>      (define/public (make-code-editor) (new scheme+copy-self%
>>                                             [kind 'code]))
>>      ;; -> (union #f text%)
>>      (define/public (get-anno-editor) anno-editor)
>>      (define/public (make-anno-editor) (new text%))
>>
>>      (define code-editor (make-code-editor))  ;; code box's editor
>>      (define anno-editor (make-anno-editor))  ;; annotation box's
>>
>>      ;;;;;;; Container snips for the text editors:
>>
>>      (define val (new vertical-alignment% [parent this]))
>>      ;; Container for the code box.  I'm using this for the ability  
>> to
>>      ;; show/hide the box:
>>      (define code-view (new vertical-alignment%
>>                             [parent val]
>>                             [show? #t]))
>>
>>      ;; Installs stretchable editor snips, if none are already  
>> installed,
>>      ;; to contain the code and anno editors.
>>      ;; (Does nothing if they already are installed, and returns #f.)
>>      ;; Returns #t if successful.
>>      (define (init-snips)
>>        (and (not (or (find-owner-snip code-editor)
>>                      (find-owner-snip anno-editor)))
>>             (let ([code-snip (new stretchable-editor-snip%
>>                                   [editor code-editor]
>>                                   [with-border? #t]
>>                                   [min-width 50])]
>>                   [anno-snip (new stretchable-editor-snip%
>>                                   [editor anno-editor]
>>                                   [with-border? #f]
>>                                   [min-width 50])])
>>               (make-object snip-wrapper% code-view code-snip)
>>               (make-object hline% code-view)
>>               (make-object snip-wrapper% val anno-snip)
>>               #t)))
>>
>>      (init-snips)
>>
>>      ;;;;;;;;; copy+paste ;;;;;;;;;
>>
>>      (define/override (copy-self)
>>        (let ([ed (new anno-pb%)])
>>          (let ([ed-code (send ed get-code-editor)]
>>                [ed-anno (send ed get-anno-editor)])
>>            (send (get-code-editor) copy-self-to ed-code)
>>            (send (get-anno-editor) copy-self-to ed-anno)
>>            ed)))
>>    )))
>>
>> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>> (define (test-w/text%)
>>  (define test-snip (new anno-snip%))
>>  (define test-pb (send test-snip get-editor))
>>  (define txt (new scheme:text%))
>>  (define f (mk-test-frame))
>>  (define c (new editor-canvas% [parent f][editor txt]))
>>  (send txt insert "\n(* x 3)\n4))" 0)
>>  (send txt insert test-snip 0)
>>  (send txt insert "(define (f x)\n(+ " 0)
>>  (send txt tabify-all)
>>  (send f show #t)
>>  )
>> (define (mk-test-frame)
>>  (new frame% [label "ah"] [width 500] [height 300]
>>       [alignment '(center center)]))
>>
>>
>>
>>
>> _________________________________________________
>>  For list-related administrative tasks:
>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>

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