Trait cstree::Syntax

pub trait Syntax: Sized + Copy + Debug + Eq {
    // Required methods
    fn from_raw(raw: RawSyntaxKind) -> Self;
    fn into_raw(self) -> RawSyntaxKind;
    fn static_text(self) -> Option<&'static str>;
}

A type that represents what items in your language can be. Typically, this is an enum with variants such as Identifier, Literal, …

The Syntax trait is the bridge between the internal cstree representation and your language’s types. This is essential for providing a SyntaxNode API that can be used with your types, as in the s_expressions example:

#[derive(Debug, Clone, Copy, PartialEq, Eq, cstree::Syntax)]
#[repr(u32)]
enum SyntaxKind {
    #[static_text("+")]
    Plus, // `+`
    #[static_text("-")]
    Minus, // `-`
    Integer,    // like `15`
    Expression, // combined expression, like `5 + 4 - 3`
    Whitespace, // whitespace is explicit
}

cstree provides a procedural macro called cstree_derive to automatically generate Syntax implementations for syntax kind enums if its derive feature is enabled.

Required Methods

fn from_raw(raw: RawSyntaxKind) -> Self

Construct a semantic item kind from the compact representation.

fn into_raw(self) -> RawSyntaxKind

Convert a semantic item kind into a more compact representation.

fn static_text(self) -> Option<&'static str>

Fixed text for a particular syntax kind. Implement for kinds that will only ever represent the same text, such as punctuation (like a semicolon), keywords (like fn), or operators (like <=).

Indicating tokens that have a static_text this way allows cstree to store them more efficiently, which makes it faster to add them to a syntax tree and to look up their text. Since there can often be many occurrences of these tokens inside a file, doing so will improve the performance of using cstree.

Implementors