[racket-dev] patch for make-base-eval

Here's another attempt at a patch. Would someone mind code reviewing it?

Ryan pointed me towards sandbox-namespace-specs and it seems to do the
trick. I also added some tests and the docs seem to compile ok.

On Wed, Oct 2, 2013 at 7:21 PM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> namespace-attach-module sets up shared state between two modules so that, in
> this case, the racket/pretty in one namespace is the same as the
> racket/pretty in the other.
>
> Try putting a printf in the top-level of racket/pretty (and in various other
> places in that code as it does what it does) and then doing the
> dynamic-require with and without the attach.
>
> Robby
>
>
> On Wed, Oct 2, 2013 at 4:58 PM, Stephen Chang <stchang at ccs.neu.edu> wrote:
>>
>> Ok here's another dumb question. Why is that namespace-attach-module
>> even needed? It seems the dynamic require on the next line does the
>> desired thing?
>>
>> On Wed, Oct 2, 2013 at 4:16 PM, Stephen Chang <stchang at ccs.neu.edu> wrote:
>> > Ok thanks for the explanations. I'll try doing one of the last two
>> > suggestions.
>> >
>> > On Wed, Oct 2, 2013 at 4:09 PM, Ryan Culpepper <ryanc at ccs.neu.edu>
>> > wrote:
>> >> No, the 'racket/pretty' module might be declared even if the symbol
>> >> isn't
>> >> defined (or "mapped") in the namespace:
>> >>
>> >>   > (define ns (make-base-namespace))
>> >>   > (define repl-ns (current-namespace))
>> >>   > (parameterize ((current-namespace ns))
>> >>       (eval '(require (only-in racket/pretty))))
>> >>   > (parameterize ((current-namespace ns))
>> >>       (namespace-attach-module repl-ns 'racket/pretty))
>> >>   namespace-attach-module: a different module with the same name is
>> >>   already in the destination namespace
>> >>     module name: "/opt/racket-5.3.6/collects/racket/pretty.rkt"
>> >>     context...:
>> >>      /opt/racket-5.3.6/collects/racket/private/misc.rkt:87:7
>> >>
>> >> And the symbol can be defined in the namespace even if the module is
>> >> not
>> >> declared:
>> >>
>> >>   > (define ns (make-base-namespace))
>> >>   > (define repl-ns (current-namespace))
>> >>   > (parameterize ((current-namespace ns))
>> >>       (eval '(define pretty-print-handler #t)))
>> >>   > (parameterize ((current-namespace ns))
>> >>       (namespace-variable-value 'pretty-print-handler))
>> >>   #t
>> >>   ;; but racket/pretty is not declared,
>> >>   ;; and #t is not a good print handler
>> >>
>> >> Ryan
>> >>
>> >>
>> >>
>> >> On 10/02/2013 03:58 PM, Stephen Chang wrote:
>> >>>>
>> >>>> A namespace is a mapping from top-level identifiers to whatever they
>> >>>> are,
>> >>>> as
>> >>>> well as a separate mapping from module names to modules (roughly).
>> >>>> What
>> >>>> you
>> >>>> care about here is the second mapping, but you're checking the first
>> >>>> with
>> >>>> the patch.
>> >>>
>> >>>
>> >>> Thanks for the explanation. That helps a lot. So the danger with my
>> >>> check is when someone has another definition of pretty-print handler
>> >>> but racket/pretty has not been attached?
>> >>>
>> >>> But given the context, ie the dynamic require on the next line, it
>> >>> seems like there's already an assumption about what the identifier I'm
>> >>> checking is, so in this specific situation, isnt my check sufficient?
>> >>>
>> >>>
>> >>>
>> >>>>
>> >>>> Robby
>> >>>>
>> >>>>
>> >>>> On Wed, Oct 2, 2013 at 2:45 PM, Stephen Chang <stchang at ccs.neu.edu>
>> >>>> wrote:
>> >>>>>
>> >>>>>
>> >>>>>> Whether that identifier exists in the namespace has nothing to do
>> >>>>>> with
>> >>>>>> whether racket/pretty can be attached.
>> >>>>>
>> >>>>>
>> >>>>> Can you explain this a little more because it's a little unintuitive
>> >>>>> to
>> >>>>> me?
>> >>>>>
>> >>>>>
>> >>>>>>
>> >>>>>> One option would be for install-pretty-printer! to just catch and
>> >>>>>> discard
>> >>>>>> the error. Evaluators for some languages would mysteriously not
>> >>>>>> have
>> >>>>>> pretty-printing turned on by default.
>> >>>>>>
>> >>>>>> Another option would be to attach racket/pretty before requiring
>> >>>>>> the
>> >>>>>> initial
>> >>>>>> language for the namespace.
>> >>>>>>
>> >>>>>> Another option is use #:pretty-print? #f when attaching
>> >>>>>> racket/pretty
>> >>>>>> would
>> >>>>>> fail.
>> >>>>>>
>> >>>>>> Ryan
>> >>>>>>
>> >>>>> _________________________
>> >>>>>    Racket Developers list:
>> >>>>>    http://lists.racket-lang.org/dev
>> >>>>
>> >>>>
>> >>>>
>> >>
>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: make-base-eval.patch
Type: application/octet-stream
Size: 7244 bytes
Desc: not available
URL: <http://lists.racket-lang.org/dev/archive/attachments/20131003/a8d4db18/attachment.obj>