1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

// 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.


#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
pub struct VarFunction(pub Rc<VarExpression>);

impl ToCss for VarFunction
{
	fn to_css<W: fmt::Write>(&self, dest: &mut W) -> fmt::Result
	{
		dest.write_str("var(")?;
		self.0.to_css(dest)?;
		dest.write_char(')')
	}
}

impl<U: Unit> Expression<U> for VarFunction
{
	/// Evaluate the VarFunction by returning the numeric value of the canonical dimension
	/// Division by zero is handled by returning the maximum possible f32 value
	/// Subtractions for UnsignedCssNumber that are negative are handled by returning 0.0
	#[inline(always)]
	fn evaluate<Conversion: FontRelativeLengthConversion<U::Number> + ViewportPercentageLengthConversion<U::Number> + PercentageConversion<U::Number> + AttributeConversion<U> + CssVariableConversion>(&self, conversion: &Conversion) -> Option<U::Number>
	{
		self.0.evaluate(conversion)
	}
}