donner::base::parser::LengthParser Class Reference

Parser for CSS <length-percentage> strings, such as "10px", "30%", "10em", etc. More...

#include "donner/base/parser/LengthParser.h"

Classes
struct	Options
	Options to modify the parsing behavior. More...
struct	Result
	Container for parse result, containing the parsed result and the number of characters that were consumed to parse it. More...

Static Public Member Functions
static ParseResult< Result >	Parse (std::string_view str, Options options=Options())
	Parse a CSS <length-percentage>, see https://www.w3.org/TR/css-values/#typedef-length-percentage.
static std::optional< Lengthd::Unit >	ParseUnit (std::string_view str)
	Parse a unit suffix from a string, such as "px" or "em".

Detailed Description

Parser for CSS <length-percentage> strings, such as "10px", "30%", "10em", etc.

For example:

auto maybeLengthResult = LengthParser::Parse("10px");
if (maybeLengthResult.hasResult()) {
  const Lengthd length = maybeLengthResult.result().length;
  doSomethingWithLength(length);
}

Member Function Documentation

Parse()

ParseResult< LengthParser::Result > donner::base::parser::LengthParser::Parse ( std::string_view str, LengthParser::Options options = Options() )

static

Parse a CSS <length-percentage>, see https://www.w3.org/TR/css-values/#typedef-length-percentage.

Equivalent to [ <length> | <percentage> ], where <percentage> will resolve to <length>.

• <length> maps to <dimension-token>:
  • https://www.w3.org/TR/css-syntax-3/#dimension-token-diagram
• <percentage> maps to <percentage-token>:
  • https://www.w3.org/TR/css-syntax-3/#percentage-token-diagram

With the following token definitions:

• <dimension-token> = <number-token> <ident-token>
• <percentage-token> = <number-token> %
• <number-token> = The result of NumberParser, a real number in either fixed or scientific notation, with optional '+' or '-' prefix.
• <ident-token> = -?-? [ a-z A-Z _ or non-ASCII ] [ a-z A-Z _ - or non-ASCII ]. However, LengthParser is limited to valid suffixes for length, as defined by Length::Unit.

If the number is 0, the <ident-token> may be omitted since 0 is unitless. This can be extended to all numbers by setting Options::unitOptional to true.

Note that this may not consume all input, the caller should handle the result of Result::consumedChars.

Parameters

str	String to parse, not all characters may be consumed.
options	Parser options.

Returns

Result containing the Length and the number of characters that were parsed.

ParseUnit()

std::optional< Lengthd::Unit > donner::base::parser::LengthParser::ParseUnit ( std::string_view str )

static

Parse a unit suffix from a string, such as "px" or "em".

Parameters

str	String containing the unit suffix, which must be a complete case-insensitive match for a supported <dimension-token> suffix, or '%' for <percentage-token>.

Returns

Lengthd::Unit corresponding to the suffix, or std::nullopt if there was no match.

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The documentation for this class was generated from the following files:

• donner/base/parser/LengthParser.h
• donner/base/parser/LengthParser.cc