[whatwg] Common number formats

[Ian Hickson]

On Tue, 25 Apr 2006, Henri Sivonen wrote:
> 
> I assume number formats in attributes consistently do not allow 
> whitespace before and after. Am I right?

The spec says (for unsigned integers):

# A string is a valid non-negative integer if it consists of one of more 
# characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).

Since space characters aren't in the range U+0030 to U+0039, they are not 
allowed, whether at the start, middle, or end.


> I assume that an explicit + sign is always forbidden. Correct?

The spec says:

# A string is a valid integer if it consists of one of more characters in 
# the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), optionally 
# prefixed with a U+002D HYPHEN-MINUS ("-") character.


> Is the - sign forbidden in front of zero? (Would be logical considering 
> that the explicit plus is forbidden.)

The - is always allowed, per the text above.


> Most definitions of integers allow leading zeros but the width and 
> height for canvas don't. Is this intentional?

This has been fixed.


> I guess floats allow leading zeros as well. Correct?

# A string is a valid floating point number if it consists of one of more 
# characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), 
# optionally with a single U+002E FULL STOP (".") character somewhere 
# (either before these numbers, in between two numbers, or after the 
# numbers), all optionally prefixed with a U+002D HYPHEN-MINUS ("-") 
# character.


> Do percentages allow leading zeros? (Leading zeros are harmless in 
> Firefox, Opera and Safari, at least.)

I haven't defined percentages yet, as we may not need them. But I imagine 
I would define them as being just a kind of integer followed by a "%" 
character.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'