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Date: Fri, 15 Dec 2006 11:21:23 -0800
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Subject: Re: Unicode support for *printf()
From: pollita@php.net (Sara Golemon)

 > I know we had discussion about *fprintf() on IRC,
 > but I'm still not clear on some stuff.
 >
 > Sara, could you please explain again why UG(unicode)
 > should  not be used as the selection for
 > php_formatted_print/php_u_formatted_print? I
 > bet a few of us are hazy on the streams Unicode/binary
 > details, so let's please clarify this and make sure
 > we're on the same page.
 >
UG(unicode) only determines what kind of data the runtime should give 
back to the script.  But we're not giving any data to the scipt here, 
we're giving data to a stream.  Whether this stream expects unicode or 
binary data has nothing to do with the setting of u.s, I could quite 
easily run the following in non-unicode semantics mode:

$fp = fopen("somefile.txt", "w");
stream_encoding($fp, "utf8");
fwrite($fp, u"\C{SNOWMAN}");

Or this in unicode.semantics mode:

$fp = fopen("somefile.bin", "wb");
fwrite($fp, b"\xFF\xFE");


Let's look at how fwrite() works (maxchars logic stripped out for 
simplicity):

if (Z_TYPE_P(zstring) == IS_UNICODE) {
	ret = php_stream_write_unicode(stream, Z_USTRVAL_P(zstring), write_len);
} else {
	convert_to_string(zstring);
	ret = php_stream_write(stream, Z_STRVAL_P(zstring), write_len);
}

Here, we rely on the user to know what kind of data they should be 
pushing at the stream.  If they push unicode, it's written as unicode, 
if they push binary, it's written as binary.  Sending the wrong type is 
dealt with by the streams layer, potentially raising an error.

What I was proposing for (v)fprintf(), since they involve multiple 
parameters, was to use the format specifier as the type hinter.  If that 
arg is unicode, then generate the string as a whole as unicode, if that 
arg is binary, then generate the string as a whole as binary.  Of course 
, it'd be even more comprehensive to do smaller writes as the string is 
processed (dispatching to write() or write_unicode() as determined by 
the arg), but that's going I bit far in my oppinion.

This keeps the responsibility (and the flexibility) of generating and 
sending the proper types on the script author, where it belongs.

-Sara