Proposal for std.path replacement

[Nick Sabalausky]

"Regan Heath" <regan at netmail.co.nz> wrote in message 
news:op.vrtj9iz454xghj at puck.auriga.bhead.co.uk...
> On Fri, 04 Mar 2011 10:13:04 -0000, Nick Sabalausky <a at a.a> wrote:
>> "Lars T. Kyllingstad" <public at kyllingen.NOSPAMnet> wrote in message
>> news:ikqabr$796$4 at digitalmars.com...
>>>
>>>>
>>>> - Windows *does* have a concept of a home dir, so maybe tilde should be
>>>> expanded even on Windows. Only problem though is that Windows has *two*
>>>> main home dirs for each user: %HOMEPATH% for user-created files and
>>>> %APPDATA% for application data. (And some others, but I don't think any
>>>> of the others are appropriate for "~") So maybe there should be these
>>>> three:
>>>>
>>>>         1. expandTilde: Exactly as it is now: expands ~ on posix, no-op
>>>>         on
>>>> windows.
>>>>
>>>>         2. expandHomeDir: On posix: Expands "~" and "%HOMEDIR%" to the
>>>> user's home directory. On windows: Expands "~" and "%HOMEDIR%" to
>>>> whatever %HOMEDIR% is set to.
>>>>
>>>>         3. expandAppDataDir: On posix: Expands "~" and "%APPDATA%" to
>>>>         the
>>>> user's home directory. On windows: Expands "~" and "%APPDATA%" to
>>>> whatever %APPDATA% is set to.
>>>
>>> On POSIX you expect to be able to use ~ anywhere you're asked to input a
>>> path/filename.  Is this the case on Windows?  Can you write %HOMEDIR%
>>> \report.doc in Word's "Open" dialog, for instance?
>>>
>>
>> No, it's just an environment variable.
>
> Actually, you can.  I just tried Textpad and Word 2010 and both accepted 
> me typing:
>
> %HOMEDRIVE%%HOMEPATH%\ (at this point they both bring up suggestions)
> %APPDATA%\ (at this point they both bring up suggestions)
>
> FYI.. my environment variables are:
>
> APPDATA=C:\Users\rheath.<domain>\AppData\Roaming
> HOMEDRIVE=C:
> HOMEPATH=\Users\rheath.<domain>
>
> I don't have HOMEDIR, .. this is on Windows 7 x64 BTW.
>

Oh, you're right. It's the same for me on XP. I must have misread the doc 
page: There is no %HOMEDIR%, that's why it didn't work when I tried it in 
notepad. The correct thing is %HOMEDRIVE%%HOMEPATH%. That works for me, and 
so does %APPDATA%.


>> In fact, it seems that % is a valid
>> filename character (I wouldn't have even guessed that), so expanding any 
>> of
>> the %BLAH% stuff in std.path is probably a bad idea after all.
>
> Not necessarily, but it might require a bit more double-checking, for 
> example..
>
> If you type the following at command prompt you get an error.
> copy con test%HOMEDRIVE%.txt
>
> "The filename, directory name, or volume label syntax is incorrect."
>
> Because %HOMEDRIVE% is expanded to C: and testC:.txt is invalid.
>
> But these both work:
> copy con test%HOMEDRIVE.txt (missing 2nd %)
> copy con test%HOMEDRIV%.txt (non-existant envvar)
>
> In the latter case you actually get a file named "test%HOMEDRIV%.txt", it 
> hasn't attempted to replace the non-existant envvar with a blank string, 
> as that would result in "test.txt".
>

FWIW, I just did a little test to see if the substitution is being done by 
the commandline itself or by the command being run. Seems to be the 
commandline itself doing the substitution. Make a little echo program in D:

import std.stdio;
void main(string[] args) {
    writeln(args[1]);
}

>dmd main.d
>main %APPDATA%
C:\Documents and Settings\Nick Sabalausky\Application Data

Next thing to test would be the file I/O API. I'm wondering if passing 
"%APPDATA%" directly to the file I/O routines would be taken literally or 
get automatically expanded. I would think it would be taken literally, but 
with all the magic that windows does, I'm not so sure. Don't have time to 
test it at the moment.