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Re: [css-variables] Is making a property negative via `-var(--width)` valid syntax?

From: Simon Pieters <simonp@opera.com>
Date: Fri, 18 Dec 2015 14:57:14 +0100
To: "Philip Walton" <philip@philipwalton.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, "Chris Lilley" <chris@w3.org>
Cc: "www-style list" <www-style@w3.org>
Message-ID: <op.x9uedo0fidj3kv@simons-mbp>
On Fri, 18 Dec 2015 13:39:51 +0100, Chris Lilley <chris@w3.org> wrote:

> Hello Simon,
> Friday, December 18, 2015, 12:05:53 PM, you wrote:
>> But it seems to me you're only likely to want it for var(). Since this
>> appears to be a pattern people use in the preprocessor world, should we
>> just support it? It wouldn't be difficult to define a new -var(x)  
>> function
>> as calc(-1 * var(x)), right? Too much of a hack? Slippery slope?
> Doesn't -var() mean either:
> a) the vendor-prefixed () for the var vendor, or
> b) a parse error because the vendor prefix should end with a - as well
> otherwise, defining it as syntactic sugar for calc seems okay.

Vendor prefix is -foo-bar, this is just -foo. It's not a parse error, it  
just gets dropped because -var() is unknown, like lolwut().

> But
> then authors will expect to negate other functions in a similar way,
> no?

Yeah, that is a risk (hence "slippery slope"), but what other function  
would you want to negate, in practice?

Simon Pieters
Opera Software
Received on Friday, 18 December 2015 13:57:46 UTC

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