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[CSS 2.1] possible problem with background value definition

From: Johannes Koch <koch@w3development.de>
Date: Mon, 17 Aug 2009 15:11:05 +0200
Message-ID: <4A8956E9.3040506@w3development.de>
To: www-style@w3.org
Hi CSS Working Group,

I see a possible problem with the value definition of the background 
property.

<http://www.w3.org/TR/CSS21/colors.html#propdef-background>:

> Value:  	[<'background-color'> || <'background-image'> || <'background-repeat'> || <'background-attachment'> || <'background-position'>] | inherit


<http://www.w3.org/TR/CSS21/about.html#value-defs>:

> A bar (|) separates two or more alternatives: exactly one of them must occur. 


As the property definitions of background-color, background-image, 
background-repeatbackground-attachment, and background-position, all 
include inherit, the value inherit would match _both_ the first 
alternative ([<'background-color'> || <'background-image'> || 
<'background-repeat'> || <'background-attachment'> || 
<'background-position'>]) _and_ the second (inherit), and so would not 
match the whole value definition, because it requires "exactly one of them".

I think this could be resolved by removing the second alternative (| 
inherit) from the background value definition.

This may also apply to other shorthand properties as well.

-- 
Johannes Koch
In te domine speravi; non confundar in aeternum.
                             (Te Deum, 4th cent.)
Received on Monday, 17 August 2009 13:11:43 GMT

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