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To: <internals@lists.php.net>, "Marcus Boerger" <helly@php.net>
References: <018101c6abf6$ee273810$0201a8c0@pc1> <105846538.20060720212112@marcus-boerger.de>
Date: Fri, 21 Jul 2006 03:08:19 -0500
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Subject: Re: [PHP-DEV] [v][sf]printf additions (#, E, g, G)
From: php_lists@realplain.com ("Matt W")

Hi Marcus,

----- Original Message ----- 
From: "Marcus Boerger"
Sent: Thursday, July 20, 2006 2:21 PM
Subject: Re: [PHP-DEV] [v][sf]printf additions (#, E, g, G)


> Hello Matt,
>
> Thursday, July 20, 2006, 2:20:46 PM, you wrote:
>
> > Hi,
>
> > I've wished there was a *printf() float specifier that wouldn't include
> > trailing zeros/point, as simply converting to string (echo, %s, etc.)
can
> > result in scientific notation, which I *don't* want (%g in
> > convert_to_string()).  The only other way that would result in what I
want
> > is number_format() with my "no-extra-zeros option" patch. ;-)  So I was
> > originally looking for how to NOT pad %f to the specified precision,
then I
> > thought why not add more of the stuff from C?  (And I see it's marked
"not
> > done" in formatted_print.c.)
>
> > Can/should I go ahead and add support for the # flag/specifier, g/G, and
E
> > (the missing compliment to e)?  Make everything work like C, except #
used
> > with f/F, which would mean "remove trailing 0's/point" -- as C's
behavior
> > with # and f (add point even when precision=0?) can be done in PHP.  (I
> > assume C's is for when precision is specified with * + parameter?)
>
> Having more conversion specifiers here won't hurt. If it can be done
> in a way compatible to other languages especially like C it should be
> done in that way. If PHP has already closed the way by choosing opposite
> defaults the opposite should everntually also work.

Sorry, not sure what you mean in the last sentence as far as the additions
I'm asking about.  I agree about compatibility with C's specifiers, but
PHP's *printf() has things that C's doesn't (%b; alternate padding
specifier) and vice versa (PHP's doesn't support "*" width/precision -- nor
does it need to; also no %n).  That's why I thought it would be OK to let #
with f/F mean no trailing 0's.

Other than that, g/G would, of course, be new.  Unless it's not needed if 1)
my "alternate form" %f idea is added, or 2) its precision would confuse
users since it means "number of significant digits" with g/G, rather than
decimal places.

# with e/E would include the decimal point even if precision=0
# with g/G *wouldn't* strip trailing 0's
# with o would include "0" prefix with non-zero result
# with x/X would include "0x"/"0X" prefix with non-zero result

All like C AFAIK, again except %#.3f, for example, wouldn't have trailing
zeros/point.  As you can probably tell, I don't like extra 0's unless
there's a *need* to always have the same width (same idea with
number_format()). :-)  I'm sure other PHP users feel the same way and would
like this alternate %f form, even if no other language has it!

> Best regards,
>  Marcus

Thanks for the reply,
Matt