Trait RuleVariants

pub trait RuleVariants<'a>:
    Sized
    + ToCursors
    + ToSpan {
    // Provided methods
    fn parse_at_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self> { ... }
    fn parse_unknown_at_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self> { ... }
    fn parse_qualified_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self> { ... }
    fn parse_unknown_qualified_rule(
        p: &mut Parser<'a>,
        _name: Cursor,
    ) -> Result<Self> { ... }
    fn bad_declaration(_: BadDeclaration<'a>) -> Option<Self> { ... }
    fn parse_rule_variants(p: &mut Parser<'a>) -> Result<Self> { ... }
}

A trait that can be used for AST nodes representing a Declaration’s Value. It offers some convenience functions for handling such values.

Provided Methods

fn parse_at_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self>

Like crate::Parse::parse() but with the additional context of the name Cursor. This cursor is known to be an AtKeyword, therefore this should return a Self reflecting a AtRule. If the AtRule is not known, or otherwise fails then this should Err and RuleVariants::parse_unknown_at_rule() can be called.

The default implementation of this method is to return an Unexpected Err.

fn parse_unknown_at_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self>

Like crate::Parse::parse() but with the additional context of the name Cursor. This cursor is known to be an AtKeyword and that RuleVariants::parse_at_rule() failed. This should therefore return a Self that represents an Unknwon AtRule, or otherwise Err.

The default implementation of this method is to return an Unexpected Err.

fn parse_qualified_rule(p: &mut Parser<'a>, _name: Cursor) -> Result<Self>

Like crate::Parse::parse() but with the additional context that the next cursor is not an AtKeyword, therefore this can attempt to parse a Qualified Rule. If the rule fails to parse, then RuleVariants::parse_unknown_qualified_rule() will be called.

The default implementation of this method is to return an Unexpected Err.

fn parse_unknown_qualified_rule( p: &mut Parser<'a>, _name: Cursor, ) -> Result<Self>

Like crate::Parse::parse() but with the additional context that the next cursor is not an AtKeyword, and that RuleVariants::parse_qualified_rule() has failed. Therefore this should attempt to parse an Unknown Qualified Rule, or Err.

The default implementation of this method is to return an Unexpected Err.

fn bad_declaration(_: BadDeclaration<'a>) -> Option<Self>

If all of the parse steps have failed, including parsing the Unknown Qualified Rule, we may want to consume a bad declaration (especially if the parser is in a nested context). This is done automatically on failing to parse an Unknown Qualified Rule, and this method is given the BadDeclaration.

This should attempt to build a Self that represents the BadDeclaration, or return None so RuleVariants::parse_rule_variants() can Err.

The default implementation of this method is to return None.

fn parse_rule_variants(p: &mut Parser<'a>) -> Result<Self>

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors