OpenEuphoria

RE: Current Directory

• Posted by Al Getz <Xaxo at aol.com> Feb 12, 2003
• 492 views

Hello again Derek,


Derek wrote:
>
>Al,
>yes I realize all that you have said is true. But That is NOT what I'm
>interested in. I'm NOT trying to change directories or drives. As I said 
>in
>my original request...
>
Yes, i understand that.  Switching drives was just to show that
the virtual environment changes with each process, and also that
is one way to view or 'get' the different 'current' directories.
By switching drives like that in a dos window you can see the
different directory names and verify that there really is such 
a notion to begin with   The dos window environment doesnt
forget the current directories for each drive, which is quite
interesting.

>
>I just want to detect if a user supplied file has been already 'seen'
>before. I thought that if I converted whatever the user supplied to a
>standard form - the FULL path specification - all I have to do then is
>compare the two specs to see if they are really the same. For 
>instance...
>
>C:\autoexec.bat
>and
>C:\temp\..\autoexec.bat
>
>refer to the same file even though the USER supplied path's are 
>different.
>
>My problem is in situation where the current drive is say C: and the 
>user
>enters "P:bin\xyz.zzy" meaning that the file they want is on the P drive 
>is
>is relative to the current directory *for that drive* and not the C: 
>drive.
>

When the system starts up, there is no such knowledge of *any* current 
directories
like that, so that means your program will have all the knowledge it 
needs
to ascertain what the user is after.  At some point after your app has 
started
up, the user had to have conveyed the directory info at some point, so 
you
could store it in a sequence indexed by drive letter:

sequence dirs,currdir
dirs={"dirA","dirB","dirC",...}
currdir=dirs['A'-64]

or something similar to that.  This should cover most platforms
because you will be handling all the user interactions yourself.


You should note however that you are
asking quite a bit out of your user if you expect them to remember 
current
directories for a possible 26 drives ('A' to 'Z').  That's one of the
benefits of using Windows' GetOpenFilename dialog.

If you absolutely cant use GetOpenFilename or whatever then you should 
have some way for your user to select the path from a list rather then
type it in.  Im sure you can come up with a way to display the necessary
info?


Another possible error could come up:

C:\Euphoria\bin\file1.txt
C:\Euphoria\Projects\bin\file1.txt

User types in:
"C:bin\file1.txt"

Which directory are they after?  Will they remember the last current
directory was C:\Euphoria and not C:\Euphoria\Projects ?


Since you are working with the current directories,
I dont know if you are aware that the current directory is invalid
for drag and dropped filenames onto the executable file?  The current
directory always gets set to "C:\" .  This means 'current_dir()' will
return "C:\" if your user drag and dropped a filename onto your
executable regardless of where the executable is located or where
the file was 'dragged' from.  This bites i know, but it's not
a Euphoria specific problem (sort of).  Windows op sys doesnt return
the correct directory either, nor does the respective compiled C call.
Granted, it could be corrected for within the Euphoria internals however
if Rob really wants to do so.


Just some ideas 


Take care,
Al