Function valuable::visit

pub fn visit(value: &impl Valuable, visit: &mut dyn Visit)

Inspects a value by calling the relevant Visit methods with value’s data.

This method calls Visit::visit_value() with the provided Valuable instance. See Visit documentation for more details.

Examples

Extract a single field from a struct. Note: if the same field is repeatedly extracted from a struct, it is preferable to obtain the associated NamedField once and use it repeatedly.

use valuable::{NamedValues, Valuable, Value, Visit};

#[derive(Valuable)]
struct MyStruct {
    foo: usize,
    bar: usize,
}

struct GetFoo(usize);

impl Visit for GetFoo {
    fn visit_named_fields(&mut self, named_values: &NamedValues<'_>) {
        if let Some(foo) = named_values.get_by_name("foo") {
            if let Some(val) = foo.as_usize() {
                self.0 = val;
            }
        }
    }

    fn visit_value(&mut self, value: Value<'_>) {
        if let Value::Structable(v) = value {
            v.visit(self);
        }
    }
}

let my_struct = MyStruct {
    foo: 123,
    bar: 456,
};

let mut get_foo = GetFoo(0);
valuable::visit(&my_struct, &mut get_foo);

assert_eq!(123, get_foo.0);

Visit: Visit NamedField: crate::NamedField