css 0.0.22

// This file is part of css. It is subject to the license terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/css/master/COPYRIGHT. No part of predicator, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
// Copyright © 2017 The developers of css. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/css/master/COPYRIGHT.


/// https://drafts.csswg.org/css-device-adapt/#descdef-viewport-zoom
#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
pub enum ViewportZoom
{
	/// The `auto` keyword.
	auto,
	
	/// invariant or calculated non-negative number or non-negative percentage
	value(CalculablePropertyValue<NumberOrPercentageUnit<CssUnsignedNumber>>),
}

impl ToCss for ViewportZoom
{
    fn to_css<W: fmt::Write>(&self, dest: &mut W) -> fmt::Result
    {
		use self::ViewportZoom::*;
		
        match *self
		{
			auto => dest.write_str("auto"),
			
            value(ref calculable) => calculable.to_css(dest),
        }
    }
}

impl ViewportZoom
{
    /// Parse a zoom value per:
    ///
    /// https://drafts.csswg.org/css-device-adapt/#descdef-viewport-zoom
    pub(crate) fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i, CustomParseError<'i>>>
	{
		use self::ViewportZoom::*;
		
		if input.try(|input| input.expect_ident_matching("auto")).is_ok()
		{
			return Ok(auto);
		}
		
		Ok(value(NumberOrPercentageUnit::parse_one_outside_calc_function(context, input)?))
    }
}