brink-syntax-native 0.0.11

Lexer and error-resilient CST for the .brink native surface (B0.5 grammar skeleton)
Documentation 
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//! Generic child/token traversal helpers for typed AST nodes.

use crate::{SyntaxKind, SyntaxNode, SyntaxToken};

use super::AstNode;

/// Returns the first child node that can be cast to `N`.
pub(super) fn child<N: AstNode>(parent: &SyntaxNode) -> Option<N> {
    parent.children().find_map(N::cast)
}

/// Returns an iterator over all children that can be cast to `N`.
pub(super) fn children<N: AstNode>(parent: &SyntaxNode) -> impl Iterator<Item = N> {
    parent.children().filter_map(N::cast)
}

/// Returns the first direct-child token matching `kind`.
pub(super) fn token(parent: &SyntaxNode, kind: SyntaxKind) -> Option<SyntaxToken> {
    parent
        .children_with_tokens()
        .filter_map(rowan::NodeOrToken::into_token)
        .find(|tok| tok.kind() == kind)
}

/// Returns an iterator over all direct-child tokens matching `kind`.
pub(super) fn tokens(parent: &SyntaxNode, kind: SyntaxKind) -> impl Iterator<Item = SyntaxToken> {
    parent
        .children_with_tokens()
        .filter_map(rowan::NodeOrToken::into_token)
        .filter(move |tok| tok.kind() == kind)
}