I had already merged it but I agree that it could probably stand to
have a little elaboration now. I'll do it.

Robby

On Sat, Mar 21, 2020 at 9:12 PM John Clements <cleme...@brinckerhoff.org> wrote:
>
> Many thanks! Should I cancel my pull request?
>
> John
>
> > On Mar 21, 2020, at 18:34, Robby Findler <ro...@cs.northwestern.edu> wrote:
> >
> > I've pushed something so that racket:text% will indent better when it
> > doesn't have a display.
> >
> > Robby
> >
> > On Fri, Mar 20, 2020 at 4:32 PM John Clements <cleme...@brinckerhoff.org> 
> > wrote:
> >>
> >> Made a pull request, many thanks!
> >>
> >> John
> >>
> >>> On Mar 20, 2020, at 1:36 PM, Robby Findler <ro...@cs.northwestern.edu> 
> >>> wrote:
> >>>
> >>> Looks right to me!
> >>>
> >>> On Fri, Mar 20, 2020 at 3:26 PM John Clements <cleme...@brinckerhoff.org> 
> >>> wrote:
> >>> Could I add a note like this to the docs for the indentation function?
> >>>
> >>> “NB: indentation results depend on the graphical context associated with 
> >>> the object; it may be necessary to associate the object with an 
> >>> editor-canvas and frame in order to get the expected results."
> >>>
> >>> That text might not actually be accurate…
> >>>
> >>> John
> >>>
> >>>> On Mar 20, 2020, at 1:16 PM, John Clements <cleme...@brinckerhoff.org> 
> >>>> wrote:
> >>>>
> >>>> Ah! this solves the issue. many thanks.
> >>>>
> >>>>> On Mar 20, 2020, at 1:03 PM, Robby Findler <ro...@cs.northwestern.edu> 
> >>>>> wrote:
> >>>>>
> >>>>> Looks like you need a display or the text gets confused about how big
> >>>>> (in pixels) characters really are:
> >>>>>
> >>>>> #lang racket/gui
> >>>>> (require framework)
> >>>>> (define f (new frame% [label ""]))
> >>>>> (define t (new racket:text%))
> >>>>> (define ec (new editor-canvas% [parent f] [editor t]))
> >>>>> (send t insert "(+        3\n4)")
> >>>>> (send t freeze-colorer)
> >>>>> (send t tabify-all)
> >>>>> (display (send t get-text))
> >>>>>
> >>>>> On Fri, Mar 20, 2020 at 2:12 PM John Clements 
> >>>>> <cleme...@brinckerhoff.org> wrote:
> >>>>>>
> >>>>>> That actually solves a bunch of problems for me… but strangely, not 
> >>>>>> the initial one. If, for instance, I tabify
> >>>>>>
> >>>>>> (+      3
> >>>>>> 4)
> >>>>>>
> >>>>>> using the tabify-all method, the line with the four gets an 
> >>>>>> indentation of 2, not 8. This is definitely different from DrRacket’s 
> >>>>>> behavior.
> >>>>>>
> >>>>>> Any idea how to fix this?
> >>>>>>
> >>>>>> (cc:ing racket-users without permission, hope that’s okay?)
> >>>>>>
> >>>>>> John
> >>>>>>
> >>>>>>
> >>>>>>> On Mar 20, 2020, at 12:05 PM, John Clements 
> >>>>>>> <cleme...@brinckerhoff.org> wrote:
> >>>>>>>
> >>>>>>> Ah! That’s probably a better solution, I’ll just do that. I searched 
> >>>>>>> for “indent”, should I try to add that as a search term for the 
> >>>>>>> “tabify-all” method?
> >>>>>>>
> >>>>>>> Many thanks!
> >>>>>>>
> >>>>>>> (Also, sending mail to the list using “us...@racket-lang.org” seems 
> >>>>>>> to be broken right now for me, sigh.)
> >>>>>>>
> >>>>>>> John
> >>>>>>>
> >>>>>>>> On Mar 20, 2020, at 12:01 PM, Robby Findler 
> >>>>>>>> <ro...@cs.northwestern.edu> wrote:
> >>>>>>>>
> >>>>>>>> I'm not sure of the details but did you consider just inserting it
> >>>>>>>> into a racket:text% and then calling the tabify-all method?
> >>>>>>>>
> >>>>>>>> Robby
> >>>>>>>>
> >>>>>>>> On Fri, Mar 20, 2020 at 1:26 PM John Clements 
> >>>>>>>> <cleme...@brinckerhoff.org> wrote:
> >>>>>>>>>
> >>>>>>>>> Hmm… followup problem. If I try to indent the string “#|\nabc\n|#” 
> >>>>>>>>> (that is, a block comment), the compute-racket-amount-to-indent 
> >>>>>>>>> method returns #f. Is this a bug, or just undocumented behavior?
> >>>>>>>>>
> >>>>>>>>> John
> >>>>>>>>>
> >>>>>>>>>> On Mar 20, 2020, at 10:41 AM, John Clements 
> >>>>>>>>>> <cleme...@brinckerhoff.org> wrote:
> >>>>>>>>>>
> >>>>>>>>>> I’m writing code to help me grade exams, and one of the issues 
> >>>>>>>>>> I’ve run into is that the code coming out of the LMS is all 
> >>>>>>>>>> totally unindented. So, for instance, a student’s response might 
> >>>>>>>>>> read:
> >>>>>>>>>>
> >>>>>>>>>> ;Closures help a function value remember what substitutions have 
> >>>>>>>>>> already been applied to it.
> >>>>>>>>>> '{vars {{x {lam {x} {+ 1 x}}}
> >>>>>>>>>> {y {lam {y} {+ 3 y}}}}
> >>>>>>>>>> {+ {x 2} {y 4}}}
> >>>>>>>>>>
> >>>>>>>>>> Obviously, it would be a lot easier to grade that if it was 
> >>>>>>>>>> indented.
> >>>>>>>>>>
> >>>>>>>>>> Excellent! A chance to whip up a quick-and-dirty auto-indenter, 
> >>>>>>>>>> using DrRacket’s indentation framework. Specifically, the 
> >>>>>>>>>> `compute-racket-amount-to-indent` method of racket:text<%>.
> >>>>>>>>>>
> >>>>>>>>>> I’m pleased to report almost total success, aside from one strange 
> >>>>>>>>>> off-by-one error that I’m looking for help with.  To see it, 
> >>>>>>>>>> here’s the result of my auto-indenter on the prior block:
> >>>>>>>>>>
> >>>>>>>>>> '{vars {{x {lam {x} {+ 1 x}}}
> >>>>>>>>>>   {y {lam {y} {+ 3 y}}}}
> >>>>>>>>>> {+ {x 2} {y 4}}}
> >>>>>>>>>>
> >>>>>>>>>> (if you’re viewing this in a proportional-width font, that’s going 
> >>>>>>>>>> to look terrible, sorry.)
> >>>>>>>>>>
> >>>>>>>>>> The issue is that the final plus line isn’t lined up with the 
> >>>>>>>>>> curly-brace that’s two chars after the end of `vars`… instead, 
> >>>>>>>>>> it’s one character to the left.
> >>>>>>>>>>
> >>>>>>>>>> A much simpler test case is simply running on “(+ 3\n4)”. Rather 
> >>>>>>>>>> than getting the 4 lined up with the 3, I get it one character to 
> >>>>>>>>>> the left.
> >>>>>>>>>>
> >>>>>>>>>> And… uh oh. A more illuminating test case occurs when I run my 
> >>>>>>>>>> code on “(+      3\n4)”. That is, I put a bunch more spaces before 
> >>>>>>>>>> the 3. After indentation, the 4 is still only indented by two 
> >>>>>>>>>> characters. So it looks like the `compute-racket-amount-to-indent` 
> >>>>>>>>>> method is not looking for the token following the first one 
> >>>>>>>>>> following the paren in the prior line (which would account for all 
> >>>>>>>>>> the spaces), but just adding one to the last position of the first 
> >>>>>>>>>> token following the paren. This makes me wonder whether DrRacket 
> >>>>>>>>>> actually uses this method to indent.
> >>>>>>>>>>
> >>>>>>>>>> Hmm.
> >>>>>>>>>>
> >>>>>>>>>> Well, here’s the code to reproduce this. Note that there’s an 
> >>>>>>>>>> obvious bug/assumption in that my code doesn’t account for any 
> >>>>>>>>>> existing leading spaces on a line, but none of my examples have 
> >>>>>>>>>> leading spaces following newlines.
> >>>>>>>>>>
> >>>>>>>>>> Advice appreciated!
> >>>>>>>>>>
> >>>>>>>>>> John
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> #lang racket
> >>>>>>>>>>
> >>>>>>>>>> (require framework)
> >>>>>>>>>>
> >>>>>>>>>> ;; given a string of racket text, return the corresponding 
> >>>>>>>>>> indented string
> >>>>>>>>>> ;; NB: CURRENTLY ASSUMES ALL LINES START WITH ZERO SPACES.
> >>>>>>>>>> (define (string-indent text-to-indent)
> >>>>>>>>>> (define t (new racket:text%))
> >>>>>>>>>> (send t erase)
> >>>>>>>>>> (send t insert text-to-indent 0)
> >>>>>>>>>> (define num-paragraphs (add1 (send t last-paragraph)))
> >>>>>>>>>> (define indents
> >>>>>>>>>> (for/list ([n (in-range num-paragraphs)])
> >>>>>>>>>> (define par-start (send t paragraph-start-position n))
> >>>>>>>>>> (list par-start
> >>>>>>>>>>       (send t compute-racket-amount-to-indent
> >>>>>>>>>>             par-start
> >>>>>>>>>>             head-sexp-type))))
> >>>>>>>>>> ;; NB: OBVIOUSLY WRONG, assumes all lines start with zero leading 
> >>>>>>>>>> spaces:
> >>>>>>>>>> ;; act in reverse order, to avoid messing up the meaning of char 
> >>>>>>>>>> posns:
> >>>>>>>>>> (for ([indent (in-list (reverse indents))])
> >>>>>>>>>> (send t set-position (first indent))
> >>>>>>>>>> (define space-string
> >>>>>>>>>> (list->string (for/list ([i (in-range (second indent))]) #\space)))
> >>>>>>>>>> (send t insert space-string))
> >>>>>>>>>> (send t get-text))
> >>>>>>>>>>
> >>>>>>>>>> ;; for now, always return 'other
> >>>>>>>>>> (define (head-sexp-type str)
> >>>>>>>>>> 'other)
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> (define text-to-indent
> >>>>>>>>>> #<<|
> >>>>>>>>>> ;Closures help a function value remember what substitutions have 
> >>>>>>>>>> already been applied to it.
> >>>>>>>>>> '{vars {{x {lam {x} {+ 1 x}}}
> >>>>>>>>>> {y {lam {y} {+ 3 y}}}}
> >>>>>>>>>> {+ {x 2} {y 4}}}
> >>>>>>>>>> |
> >>>>>>>>>> )
> >>>>>>>>>>
> >>>>>>>>>> (displayln (string-indent text-to-indent))
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> (displayln (string-indent "
> >>>>>>>>>> (+ 3
> >>>>>>>>>> 4)"))
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> (module+ test
> >>>>>>>>>> (require rackunit)
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> (check-equal? (string-indent "
> >>>>>>>>>> (+ 3
> >>>>>>>>>> 4)")
> >>>>>>>>>>           "
> >>>>>>>>>> (+ 3
> >>>>>>>>>> 4)")
> >>>>>>>>>>
> >>>>>>>>>> (check-equal? (string-indent "
> >>>>>>>>>> (+  3
> >>>>>>>>>> 4)")
> >>>>>>>>>>           "
> >>>>>>>>>> (+  3
> >>>>>>>>>> 4)")
> >>>>>>>>>>
> >>>>>>>>>> (check-equal? (string-indent "
> >>>>>>>>>> (+        3
> >>>>>>>>>> 4)")
> >>>>>>>>>>           "
> >>>>>>>>>> (+        3
> >>>>>>>>>>     4)"))
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> --
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> >>>>
> >>>
> >>>
> >>>
> >>>
> >>> --
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> >>
> >>
> >>
>
>
>

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