From: L7 <jesse.r.brown@...>
Date: 2006-08-19T03:25:03+09:00
Subject: Re: Bug in sprintf?

Wes Gamble wrote:
> Thanks for the comprehensive response.
>
> Well, I can't really argue with the C implementation, of course...
>
> BUT
>
> it feels like if I declare my intent to interpret the sprintf input as a
> _decimal_ number with %d (there's a %o if I wanted octal), that is
> should allow for leading zeroes.
>
> My intent in writing sprintf("%d", '08') is to say take the string 08
> and turn it into the number 8.
>
> It isn't to say here's an octal number, please convert it to decimal for
> me.  If I think the string is octal, I'll use %o for that.
>
> So in the spirit of what the user expects, I still think this smells
> bad.
>
> Feel free to convince me otherwise.
>

Consider it this way:

The format character (%d) is a way to know how the values collected
will be displayed. The values, in this case arguments to %d, are not
intrepreted (necessarily) at the same time as the format characters and
therefor are seperate entities. Taking any [legal] value and passing it
to %d will result in a decimal number printed out.
However, the parsing aspect is entirely different. There is no format
that says: 'this is how to interpret me' - other than the syntax.
If you take that away you create ambiguities. If the syntax is longer
how to distinguish a value, it must be explicitly tied to a format
string/character.

Imagine the confusion when you try to
#define FORTY_TWO_HEX %x 2a
#define FORTY_TWO_OCT %o 52
#define FORTY_TOW_DEC %d 42
(Since the two are now linked, you need the format characters. Or
should it be %x 42, %o 42 ... you get the idea)

instead of
#define FORTY_TWO_HEX 0x2a
#define FORTY_TWO_OCT 052
#define FORTY_TWO_DEC 42

While it may be easy/convenient to suggest allowing a format character
determine a value, it breaks when not in a specific setting.



> Thanks again,
> Wes
> 
> -- 
> Posted via http://www.ruby-forum.com/.