Running on Linux: os.getenv('username') returns None, program aborts about slic3rconfigprettyprint

[7eggert]

The current code is correct, but the try / except can be removed as there will be no exception.
Putting in a second parameter for getenv(varname, default) does already everything you intend to do, and you may .title() the result safely if you desire.

Below is a lengthy explanation, not to put in code:

If you were to handle not having a user name by doing anything beyond having a default, you'd need a None return value by not providing a default (omit the second parameter on the inner call to getenv).

Depending on weather you call .title() immediately: (// being a line break)
try: // currentusername = getenv(…).title() // except: // (print message, set default)

Or not: If currentusername is not None: // currentusername = currentusername.title() //else: // (print message, set default, slap user)

Both are correct, but the exception needs a comment explaining why you'd expect to arrive there:
# If neither environment variable is set, .title() will throw an exception on the Null value

Also I see you're testing for not-supplied parameters by converting to string and lowercasing (e.g. line 118, if str(filename).lower() == 'none'). I assume if filename is None would be correct, but I don't test that now.

[foreachthing]

Works in Windows.
No reason not to use it: 363a486

[7eggert]

If you have a default parameter on the inner os.getenv('USER','default_string'), then there will not be any exception. If you want that, you should remove that, so None will be returned and .None.title() will throw the exception.

[foreachthing]

Please try the new commit and let me know if that works now.
Sure, None is not a string ... maybe str(os.getenv('USER','default_string')).title() would have sufficed.

[7eggert]

If you have a default parameter, then there will always be a string being returned and you can .title it.
Thus, currentusername = os.getenv('username', os.getenv('USER','Your Name')).title() will never throw an exception.

My reasoning was that if you want to handle not finding the user name by exception, then you MUST NOT use a default parameter, but currentusername = os.getenv('username', os.getenv('USER')).title(), then catch the exception and do whatever you want there.

Also: currentusername.title() is documented to not modify the string.

If you want to use "Your Name" as a default, you can just put in that default, you will not get an exception as you will not get a None return value. Then you can call .title() and be done.

I'd suggest leaving it empty or to print a line so you can write in your name.

[foreachthing]

Also: currentusername.title() is documented to not modify the string.

Yeah, I thought about that too ...
And, nah, I don't like exceptions :-) ! If someone has no username/USER in his/her system, so be it!

[foreachthing]

Dude! I appreciate your lesson in programming (I am no programmer, obviously) but it's just a username on a report! Nothing more, nothing less!
I expect, if someone really will use this script, that he/she will provide the actual name - not the username on the computer. I use just some bogus thing myself.... so, if the script doesn't 'see' a username, then use a default. This will let the user know "hey, I can put my real name on this thing! : -)
I'll look over it again not to use useless/needless code - thanks!

[7eggert]

You need help, therefore I do help as much as I can. HTH, nor more nor less. Also I learned a little bit of silly snake.-)