Query API for AST traversal

The Query API is provided by the bsharp_syntax crate and re-exported by bsharp_analysis for convenience. It replaces older navigation traits, but the Query API itself is current and not deprecated.

Core types

• NodeRef<'a>: a thin enum over AST nodes (CompilationUnit, Namespace, Class, Struct, Interface, Enum, Record, Delegate, Method, Statement, Expression, plus top-level items). Origin: bsharp_syntax::node::ast_node::NodeRef (re-exported as bsharp_analysis::framework::NodeRef).
• Query<'a>: a fluent helper to enumerate descendants and select typed nodes. Origin: bsharp_syntax::query::Query (re-exported as bsharp_analysis::framework::Query).

#![allow(unused)]
fn main() {
use bsharp_analysis::framework::{NodeRef, Query};
use bsharp_syntax::CompilationUnit;
use bsharp_syntax::{ClassDeclaration, MethodDeclaration};

fn all_classes<'a>(cu: &'a CompilationUnit) -> Vec<&'a ClassDeclaration> {
    Query::from(NodeRef::CompilationUnit(cu))
        .of::<ClassDeclaration>()
        .collect()
}

fn all_methods<'a>(cu: &'a CompilationUnit) -> Vec<&'a MethodDeclaration> {
    Query::from(NodeRef::CompilationUnit(cu))
        .of::<MethodDeclaration>()
        .collect()
}
}

Descendant enumeration

Query::descendants() walks the tree using Children implemented for NodeRef.

#![allow(unused)]
fn main() {
use bsharp_analysis::framework::{NodeRef, Query};
use bsharp_syntax::statements::Statement;

fn all_statements<'a>(cu: &'a CompilationUnit) -> Vec<&'a Statement> {
    Query::from(NodeRef::CompilationUnit(cu))
        .of::<Statement>()
        .collect()
}
}

Filtering

Use filter_typed to filter by predicate.

#![allow(unused)]
fn main() {
use analysis::syntax::declarations::ClassDeclaration;

let public_classes: Vec<&ClassDeclaration> =
    Query::from(NodeRef::CompilationUnit(&cu))
        .filter_typed::<ClassDeclaration>(|c| c.modifiers.iter().any(|m| m.is_public()))
        .collect();
}

Best practices

• Prefer Query for node enumeration across passes.
• For hot path statement/expression analysis, use shared helpers (metrics::shared) or a small local walker when necessary.
• Keep passes stateless and deterministic; feed inputs via AnalysisSession artifacts.

Implementation notes

The Children/Extract traits are implemented for common AST nodes, enabling Query::of<T>() to return strong types. See:

• src/bsharp_syntax/src/query/ for Children, Extract, Query.
• src/bsharp_syntax/src/node/ast_node.rs for NodeRef.