Crate cssparser

Expand description

Implementation of CSS Syntax Module Level 3 for Rust.

§Input

Everything is based on Parser objects, which borrow a &str input. If you have bytes (from a file, the network, or something) and want to support character encodings other than UTF-8, see the stylesheet_encoding function, which can be used together with rust-encoding or encoding-rs.

§Conventions for parsing functions

Take (at least) a input: &mut cssparser::Parser parameter
Return Result<_, ()>
When returning Ok(_), the function must have consumed exactly the amount of input that represents the parsed value.
When returning Err(()), any amount of input may have been consumed.

As a consequence, when calling another parsing function, either:

Any Err(()) return value must be propagated. This happens by definition for tail calls, and can otherwise be done with the ? operator.
Or the call must be wrapped in a Parser::try call. try takes a closure that takes a Parser and returns a Result, calls it once, and returns itself that same result. If the result is Err, it restores the position inside the input to the one saved before calling the closure.

Examples:

// 'none' | <image>
fn parse_background_image(context: &ParserContext, input: &mut Parser)
                                    -> Result<Option<Image>, ()> {
    if input.try_parse(|input| input.expect_ident_matching("none")).is_ok() {
        Ok(None)
    } else {
        Image::parse(context, input).map(Some)  // tail call
    }
}

// [ <length> | <percentage> ] [ <length> | <percentage> ]?
fn parse_border_spacing(_context: &ParserContext, input: &mut Parser)
                          -> Result<(LengthOrPercentage, LengthOrPercentage), ()> {
    let first = LengthOrPercentage::parse?;
    let second = input.try_parse(LengthOrPercentage::parse).unwrap_or(first);
    (first, second)
}

Modules§

Delimiter: Delimiters constants.
color: General color-parsing utilities, independent on the specific color storage and parsing implementation.

Macros§

_cssparser_internal_max_len
ascii_case_insensitive_phf_map: Define a function $name(&str) -> Option<&'static $ValueType>
match_byte: Expand a TokenStream corresponding to the match_byte macro.
match_ignore_ascii_case: Expands to a match expression with string patterns, matching case-insensitively in the ASCII range.

Structs§

BasicParseError: The fundamental parsing errors that can be triggered by built-in parsing routines.
CowRcStr: A string that is either shared (heap-allocated and reference-counted) or borrowed.
CssStringWriter: A fmt::Write adapter that escapes text for writing as a double-quoted CSS string. Quotes are not included.
Delimiters: A set of characters, to be used with the Parser::parse_until* methods.
ParseError: Extensible parse errors that can be encountered by client parsing implementations.
Parser: A CSS parser that borrows its &str input, yields Tokens, and keeps track of nested blocks and functions.
ParserInput: The owned input for a parser.
ParserState: A capture of the internal state of a Parser (including the position within the input), obtained from the Parser::position method.
RuleBodyParser: Provides an iterator for rule bodies and declaration lists.
SourceLocation: The line and column number for a given position within the input.
SourcePosition: A position from the start of the input, counted in UTF-8 bytes.
StyleSheetParser: Provides an iterator for rule list parsing at the top-level of a stylesheet.
UnicodeRange: One contiguous range of code points.

Enums§

BasicParseErrorKind: Details about a BasicParseError
ParseErrorKind: Details of a ParseError
Token: One of the pieces the CSS input is broken into.
TokenSerializationType: A category of token. See the needs_separator_when_before method.

Traits§

AtRuleParser: A trait to provide various parsing of at-rules.
DeclarationParser: A trait to provide various parsing of declaration values.
EncodingSupport: Abstraction for avoiding a dependency from cssparser to an encoding library
QualifiedRuleParser: A trait to provide various parsing of qualified rules.
RuleBodyItemParser: A parser for a rule body item.
ToCss: Trait for things the can serialize themselves in CSS syntax.

Functions§

parse_important: Parse !important.
parse_nth: Parse the An+B notation, as found in the :nth-child() selector. The input is typically the arguments of a function, in which case the caller needs to check if the arguments’ parser is exhausted. Return Ok((A, B)), or an Err(..) for a syntax error.
parse_one_declaration: Parse a single declaration, such as an ( /* ... */ ) parenthesis in an @supports prelude.
parse_one_rule: Parse a single rule, such as for CSSOM’s CSSStyleSheet.insertRule.
serialize_identifier: Write a CSS identifier, escaping characters as necessary.
serialize_name: Write a CSS name, like a custom property name.
serialize_string: Write a double-quoted CSS string token, escaping content as necessary.
stylesheet_encoding: Determine the character encoding of a CSS stylesheet.

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