[Python-Dev] file modes (was: just say no...)

[Greg Stein]

On Thu, 18 Nov 1999, M.-A. Lemburg wrote:
> Tim Peters wrote:
> > [MAL]
> > > File objects opened in text mode will use "t#" and binary
> > > ones use "s#".
> > 
> > [Greg Stein]
> > > ...
> > > The real annoying thing would be to assume that opening a file as 'r'
> > > means that I *meant* text mode and to start using "t#".
> > 
> > Isn't that exactly what MAL said would happen?  Note that a "t" flag for
> > "text mode" is an MS extension -- C doesn't define "t", and Python doesn't
> > either; a lone "r" has always meant text mode.
> 
> Em, I think you've got something wrong here: "t#" refers to the
> parsing marker used for writing data to files opened in text mode.

Nope. We've got it right :-)

Tim and I used 'r' and "t" to refer to file-open modes. I used "t#" to
refer to the parse marker.

>...
> I guess you won't notice any difference: strings define both
> interfaces ("s#" and "t#") to mean the same thing. Only other
> buffer compatible types may now fail to write to text files
> -- which is not so bad, because it forces the programmer to
> rethink what he really intended when opening the file in text
> mode.

It *is* bad if it breaks my existing programs in subtle ways that are a
bitch to track down.

> Besides, if you are writing portable scripts you should pay
> close attention to "r" vs. "rb" anyway.

I'm not writing portable scripts. I mentioned that once before. I don't
want a difference between 'r' and 'rb' on my Linux box. It was never there
before, I'm lazy, and I don't want to see it added :-).

Honestly, I don't know offhand of any Python types that repond to "s#" and
"t#" in different ways, such that changing file.write would end up writing
something different (and thereby breaking existing code).

I just don't like introduce text/binary to *nix platforms where it didn't
exist before.

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/