[plt-scheme] changing current-directory in Dr Scheme?

Hi all -

How does (current-directory) actually work, specifically in Dr Scheme REPL?


I am trying to dynamically determine module's provided variables based on
Eli's code in
http://list.cs.brown.edu/pipermail/plt-scheme/2003-November/003698.html.  It
works if the module path happens to be the current directory, but fails if
not, for modules that require another module "relatively".

Example:

; c:\data\scheme\lib\util\foo.scm
(module foo mzscheme
  (define x 1)
  (provide (all-defined)))

; c:\data\scheme\lib\util\util.scm
(module util mzscheme
  (require "foo.scm")
  (define y 2)
  (provide (all-from "foo.scm"))
  (provide (all-defined)))

Dr Scheme REPL
> (current-directory)
#<path:C:\Local\PLT>
> (parameterize ((current-directory "c:\\data\\scheme\\lib\\util\\"))
    (expand (with-input-from-file "c:\\data\\scheme\\lib\\util\\util.scm"
read)))
Error: open-input-file: cannot open input file: "c:\Local\PLT\foo.scm" (The
system cannot find file specified.; errno=2)

This behavior is the same even when I attempt to modify REPL
current-directory first then expand the file.  When I verify
(current-directory) it is indeed modified, but expand just simply doesn't
work from the changed directory - this is puzzling (I have also previously
run into another similar situation with a different function that I forgot,
so I don't think this is specifically due to (expand)).

> (current-directory "c:\\data\\scheme\\lib\\util\\")
> (current-directory)
#<path:c:\data\scheme\lib\util>
> (expand (with-input-from-file "c:\\data\\scheme\\lib\\util\\util.scm"
read))
Error: open-input-file: cannot open input file: "c:\Local\PLT\foo.scm" (The
system cannot find file specified.; errno=2)

How can I actually change the current-directory?

Thanks,
yinso

-- 
http://www.yinsochen.com
...continuous learning...
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