[racket-dev] Should BSL signal an error on (require ...) in an unsaved buffer?

On Tue, Jun 28, 2011 at 8:19 AM, John Clements
<clements at brinckerhoff.org> wrote:
>
> On Jun 27, 2011, at 5:10 PM, Robby Findler wrote:
>
>> On Tue, Jun 28, 2011 at 7:52 AM, John Clements
>> <clements at brinckerhoff.org> wrote:
>>>
>>> On Jun 27, 2011, at 4:45 PM, Robby Findler wrote:
>>>
>>>> We're talking about relative requires only, right?
>>>>
>>>> How are you proposing to signal the error?
>>>
>>> My guess about how this works--correct me if I'm wrong--is that for unsaved buffers, DrR sets a parameter such that the expanded code has the current directory as (uh, part of?) the syntax-source of the expanded source.  I'm guessing that I'm not right, or it would be as simple as disabling this for programs written in BSL et al.
>>
>> DrRacket does indeed set current-directory and could instead signal an
>> error instead of setting it. That would mean no unsaved file would
>> run, however. Is that really desired?
>
> Would it not be possible to set the syntax-source in such a way that relative requires would fail? We may be out of DrR and into just plain R here.

Yes, we have to be, I'm pretty sure.

> Indeed, I would be happy if buffers without a recorded save location couldn't make relative requires in *any* language level, though I realize that such a change would be more likely to have repercussions elsewhere.

I think that would probably require a new parameter that controls
where relative requires are relative to being exported and allowing it
to have a value that says "no relative requires allowed".
(current-load-relative-directory is maybe already this, without the
extra functionality, maybe?)

> I suppose there could be situations where users dynamically create syntax objects and set the current directory rather than setting the syntax-source of the objects, though that doesn't sound like the most robust way to write the code.

I don't understand this comment.

(I believe that the source field of a syntax objects is not involved
in resolving relative requires.)

Robby