[racket] Evaluating Racket source files from within another Racket source file

The syntax of `enter!' is supposed to be like `require', where the
module name is not quoted. If you remove the quote, then something like

 (enter! file/gif)

doesn't work.


It would make sense to move the transitive module-reloading part of
`enter!' to a a new module and provide a `dynamic-re-require' function
that's similar to `do-enter!' --- and that would more directly be what
you want, I think. I'll look into that.


At Sun, 28 Apr 2013 00:09:13 -0700, Matthew Butterick wrote:
> Thanks, I'll try that. However, I still think there might be a bug in
> racket/enter.rkt. Currently lines 10-11 look like this:
> 
>      [(enter! mod flag ...) (andmap keyword? (syntax->datum #'(flag ...)))
>       #'(do-enter! 'mod '(flag ...))]
> 
> But when I remove the quoting from mod in line 11, like so …
> 
>      [(enter! mod flag ...) (andmap keyword? (syntax->datum #'(flag ...)))
>       #'(do-enter! mod '(flag ...))]
> 
> Then (enter! module-name-variable) works as hoped, and (enter!
> "module-name-string.rkt") still works too.
> 
> Making it work proves nothing ;) I will file a bug report.
> 
> Matthew Butterick
> 
> 
> 
> On Sat, Apr 27, 2013 at 7:17 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> 
> > I think you probably want to create a new namespace for each
> > instantiation of the Scribble module, and attach Scribble (or whatever
> > modules you want to stay the same across runs) to the namespace before
> > `dynamic-require'ing the module in the new namespace:
> >
> >  #lang racket/base
> >  (require scribble/base)
> >
> >  (define (re-run module-path)
> >    (define ns (make-base-namespace))
> >    (namespace-attach-module (current-namespace) 'scribble/base)
> >    (parameterize ([current-namespace ns])
> >      (dynamic-require module-path #f)))
> >
> >
> > At Sat, 27 Apr 2013 19:08:53 -0700, Matthew Butterick wrote:
> > > OK, so the proposed solution failed once I tried to pass in the module
> > name
> > > as a variable. Even though enter! claims to take a module-path as an
> > > argument, this will not work:
> > >
> > > (define name "module.rkt")
> > > (module-path? name) ; reports #t
> > > (enter! name) ;  error: collection "name" not found
> > >
> > > enter! is treating "name" as a module path instead of resolving it as a
> > > defined term. What I can't tell is whether this is mandatory behavior for
> > > enter!, or if it's a bug in the enter! macro. (I did look at enter.rkt,
> > but
> > > this week, it's over my head.)
> > >
> > > Matthew Butterick
> > >
> > >
> > > On Sat, Apr 27, 2013 at 6:16 PM, Matthew Butterick
> > > <mb.list.acct at gmail.com>wrote:
> > >
> > > > Aha, combining enter! with dynamic-require seems to do the trick:
> > > >
> > > > (define (route req)
> > > >     (enter! "module.rkt")
> > > >     (define foo (dynamic-require "module.rkt" 'foo))
> > > >     (response/xexpr `(p ,(format "~a" foo))))
> > > >
> > > > Once this route is running in the web server, I can make changes to
> > > > module.rkt, then click reload in the browser, and the changes will
> > appear
> > > > in the browser.
> > > >
> > > > If this is a terrible idea let me know, otherwise I'll consider this
> > > > solved.
> > > >
> > > >
> > > > On Sat, Apr 27, 2013 at 9:56 AM, Matthew Butterick <
> > mb.list.acct at gmail.com
> > > > > wrote:
> > > >
> > > >> I'm building a website using Scribble as the source format. As a
> > > >> development tool, I've built a web server in Python that lets me view
> > all
> > > >> my Scribble source files and look at them in different states of
> > > >> processing. To view the results of the Scribble files, the Python
> > server
> > > >> just sends the files to Racket via a system command (os.Popen) and
> > reads
> > > >> the result. This works but it's slow, because it  has to launch a new
> > > >> Racket thread for every request.
> > > >>
> > > >> I thought I could speed things up by rewriting the development web
> > server
> > > >> in Racket. But having tried a few approaches, I'm not sure how to
> > duplicate
> > > >> this functionality within a Racket web servlet:
> > > >>
> > > >> *(require <modulename>) *
> > > >> This only gets evaluated once, when the server is started. That
> > doesn't
> > > >> help, since the <filename> is going to be passed in as a parameter
> > while
> > > >> the server is running.
> > > >>
> > > >> *(dynamic-require <** modulename **>) *
> > > >> This gets evaluated only when invoked, and thus can take <modulename>
> > as
> > > >> a parameter, but then <filename> can't be reloaded (this is
> > essential, as
> > > >> the point of the system is to be able to edit the files and see the
> > changes
> > > >> in the web browser immediately)
> > > >>
> > > >> *(enter! <modulename>)*
> > > >> This reloads the file, but it's not clear how to get access to names
> > > >> provided by <modulename>. (The documentation for enter! suggests that
> > this
> > > >> is not how it's meant to be used anyhow.)
> > > >>
> > > >> Obviously, I could call a new instance of Racket as a system command,
> > but
> > > >> that wouldn't offer any advantage over the current approach.
> > > >>
> > > >>
> > > >> I suppose what I'm looking for is an equivalent of the Python
> > > >> reload(<modulename>) command.
> > > >>
> > > >>
> > > >> Matthew Butterick
> > > >>
> > > >
> > > >
> > > ____________________
> > >   Racket Users list:
> > >   http://lists.racket-lang.org/users
> >