Trait Visitor 

pub trait Visitor<'ast>
where
    Self: Sized,
{
    // Provided methods
    fn visit_expr(&mut self, expr: &'ast Expr) { ... }
    fn visit_literal(&mut self, _literal: &'ast Literal) { ... }
    fn visit_identifier(&mut self, _ident: &'ast str) { ... }
    fn visit_type(&mut self, _cel_type: &'ast CelType) { ... }
    fn visit_unary_op(&mut self, op: UnaryOperator, operand: &'ast Expr) { ... }
    fn visit_binary_op(
        &mut self,
        op: BinaryOperator,
        left: &'ast Expr,
        right: &'ast Expr,
    ) { ... }
    fn visit_conditional(
        &mut self,
        cond: &'ast Expr,
        true_branch: &'ast Expr,
        false_branch: &'ast Expr,
    ) { ... }
    fn visit_list(&mut self, elements: &'ast [Expr]) { ... }
    fn visit_field_access(&mut self, base: &'ast Expr, field: &'ast str) { ... }
    fn visit_call(&mut self, target: &'ast Expr, args: &'ast [Expr]) { ... }
    fn visit_index(&mut self, base: &'ast Expr, index: &'ast Expr) { ... }
    fn visit_map_literal(&mut self, entries: &'ast [(Expr, Expr)]) { ... }
    fn visit_message_literal(
        &mut self,
        type_name: &'ast str,
        fields: &'ast [(String, Expr)],
    ) { ... }
    fn visit_has(&mut self, target: &'ast Expr) { ... }
    fn visit_comprehension(
        &mut self,
        op: ComprehensionOp,
        target: &'ast Expr,
        iter_var: &'ast str,
        predicate: &'ast Expr,
    ) { ... }
    fn visit_map(
        &mut self,
        target: &'ast Expr,
        iter_var: &'ast str,
        filter: Option<&'ast Expr>,
        transform: &'ast Expr,
    ) { ... }
}

A trait for visiting nodes in the AST in an immutable fashion.

The methods in this trait are called during a depth-first traversal of the AST. The default implementation of each visit_* method recursively visits the children of the node. To customize the behavior, implement this trait and override the methods for the nodes you are interested in.

Provided Methods

fn visit_expr(&mut self, expr: &'ast Expr)

Visits any Expr node. This is the main dispatch method.

fn visit_literal(&mut self, _literal: &'ast Literal)

Visits a Literal node (e.g., 123, "hello").

fn visit_identifier(&mut self, _ident: &'ast str)

Visits an Identifier node (e.g., request).

fn visit_type(&mut self, _cel_type: &'ast CelType)

Visits a Type node (e.g., int, string).

fn visit_unary_op(&mut self, op: UnaryOperator, operand: &'ast Expr)

Visits a UnaryOp node (e.g., !true).

fn visit_binary_op( &mut self, op: BinaryOperator, left: &'ast Expr, right: &'ast Expr, )

Visits a BinaryOp node (e.g., a + b).

fn visit_conditional( &mut self, cond: &'ast Expr, true_branch: &'ast Expr, false_branch: &'ast Expr, )

Visits a Conditional node (e.g., cond ? true_br : false_br).

fn visit_list(&mut self, elements: &'ast [Expr])

Visits a List literal (e.g., [1, 2, 3]).

fn visit_field_access(&mut self, base: &'ast Expr, field: &'ast str)

Visits a FieldAccess node (e.g., a.b).

fn visit_call(&mut self, target: &'ast Expr, args: &'ast [Expr])

Visits a Call node (e.g., func(arg1, arg2)).

fn visit_index(&mut self, base: &'ast Expr, index: &'ast Expr)

Visits an Index node (e.g., list[0]).

fn visit_map_literal(&mut self, entries: &'ast [(Expr, Expr)])

Visits a MapLiteral node (e.g., {'key': 'value'}).

fn visit_message_literal( &mut self, type_name: &'ast str, fields: &'ast [(String, Expr)], )

Visits a MessageLiteral node (e.g., Point{x: 1, y: 2}).

fn visit_has(&mut self, target: &'ast Expr)

Visits a Has macro (e.g., has(msg.field)).

fn visit_comprehension( &mut self, op: ComprehensionOp, target: &'ast Expr, iter_var: &'ast str, predicate: &'ast Expr, )

Visits a Comprehension macro (e.g., list.all(i, i > 0)).

fn visit_map( &mut self, target: &'ast Expr, iter_var: &'ast str, filter: Option<&'ast Expr>, transform: &'ast Expr, )

Visits a Map macro (e.g., items.map(i, i.price)).

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