Trait ReceiverMacroExpander 

pub trait ReceiverMacroExpander:
    Fn(&MacroExprFactory<'_>, Expr, Vec<Expr>) -> Option<Expr>
    + Send
    + Sync { }

Trait for receiver macro expansion functions.

A receiver macro expander receives a target expression and a list of arguments, then produces a transformed expression. Receiver macros are triggered by method calls on a target object.

Type Requirements

The expander function must be:

• Fn(&mut MacroExprFactory, Expr, Vec<Expr>) -> Option<Expr>: The expansion signature
• Send + Sync: Thread-safe for use in concurrent environments
• 'static: No borrowed references in the closure

Parameters

• factory: Factory for creating new expression nodes
• target: The receiver expression (the object before the dot)
• args: The argument list passed to the method

Return Value

• Some(expr): The macro expansion succeeded and expr replaces the original call
• None: The macro cannot be expanded (keeps the original expression)

Examples

// Macro for optional chaining: target.get_or(default)
fn get_or_macro(
    factory: &mut MacroExprFactory,
    target: Expr,
    mut args: Vec<Expr>
) -> Option<Expr> {
    if args.len() != 1 {
        return None;
    }
     
    let default_value = args.pop()?;
     
    // Expand to: target != null ? target : default_value
    Some(factory.new_call("_?_:_", &[
        factory.new_call("_!=_", &[target.clone(), factory.new_const(())]),
        target,
        default_value,
    ]))
}

Implementors

impl<'f, F> ReceiverMacroExpander for F

where F: Fn(&MacroExprFactory<'_>, Expr, Vec<Expr>) -> Option<Expr> + Send + Sync + 'f,