style/typed_om/
numeric_declaration.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5//! Typed OM Numeric Declaration.
6
7use crate::derives::*;
8use crate::parser::{Parse, ParserContext};
9use crate::typed_om::numeric::NoCalcNumeric;
10use crate::values::specified::calc::{CalcNode, CalcParseFlags, PercentageContext};
11use crate::values::specified::{
12    NoCalcAngle, NoCalcLength, NoCalcNumber, NoCalcPercentage, NoCalcTime,
13};
14use cssparser::{Parser, Token};
15use style_traits::values::specified::AllowedNumericType;
16use style_traits::{ParseError, StyleParseErrorKind};
17
18/// A numeric declaration, with or without a `calc()` expression.
19#[derive(Clone, ToTyped)]
20pub enum NumericDeclaration {
21    /// A numeric value without a `calc()` expression.
22    NoCalc(NoCalcNumeric),
23
24    /// A numeric value represented by a `calc()` expression.
25    ///
26    /// <https://drafts.csswg.org/css-values/#calc-notation>
27    Calc(CalcNode),
28}
29
30impl Parse for NumericDeclaration {
31    /// <https://drafts.css-houdini.org/css-typed-om-1/#dom-cssnumericvalue-parse>
32    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ParseError> {
33        // Step 1.
34        let token = input.next()?;
35
36        // Step 2.
37        match *token {
38            Token::Number { value, .. } => Ok(Self::NoCalc(NoCalcNumeric::Number(
39                NoCalcNumber::new(value),
40            ))),
41
42            Token::Percentage { unit_value, .. } => Ok(Self::NoCalc(NoCalcNumeric::Percentage(
43                NoCalcPercentage::new(unit_value),
44            ))),
45
46            Token::Dimension {
47                value, ref unit, ..
48            } => {
49                if let Ok(length) = NoCalcLength::parse_dimension_with_context(context, value, unit)
50                {
51                    return Ok(Self::NoCalc(NoCalcNumeric::Length(length)));
52                }
53
54                if let Ok(angle) = NoCalcAngle::parse_dimension(value, unit) {
55                    return Ok(Self::NoCalc(NoCalcNumeric::Angle(angle)));
56                }
57
58                if let Ok(time) = NoCalcTime::parse_dimension(value, unit) {
59                    return Ok(Self::NoCalc(NoCalcNumeric::Time(time)));
60                }
61
62                Err(ParseError::unexpected_token())
63
64                // Step 3.
65
66                // TODO: A type should be created from unit and if that fails, the failure
67                // should be propagated here.
68            },
69
70            Token::Function(ref name) => {
71                let function = CalcNode::math_function(context, name)?;
72                let node = CalcNode::parse(
73                    context,
74                    input,
75                    function,
76                    CalcParseFlags::new(PercentageContext::allowed()),
77                )?;
78
79                let allow_all_types = AllowedNumericType::All;
80                let _ = node
81                    .clone()
82                    .into_length_or_percentage(allow_all_types)
83                    .map_err(|()| ParseError::custom(StyleParseErrorKind::UnspecifiedError))?;
84
85                // TODO: Add support for other values represented by a `calc()` expression.
86
87                Ok(Self::Calc(node))
88            },
89
90            _ => Err(ParseError::unexpected_token()),
91        }
92    }
93}
style/typed_om/numeric_declaration.rs

style/typed_om/
numeric_declaration.rs
