Module glib::value

Expand description

Value binding and helper traits.

The type of a Value is dynamic in that it generally isn’t known at compile time but once created a Value can’t change its type.

SendValue is a version of Value that can only store types that implement Send and as such implements Send itself. It dereferences to Value so it can be used everywhere Value references are accepted.

Supported types are bool, i8, u8, i32, u32, i64, u64, f32, f64, String and objects (T: IsA<Object>).

Examples

use glib::prelude::*; // or `use gtk::prelude::*;`
use glib::Value;

// Value implement From<&i32>, From<&str> and From<Option<&str>>.
// Another option is the `ToValue` trait.
let mut num = 10.to_value();
let mut hello = Value::from("Hello!");
let none: Option<&str> = None;
let str_none = none.to_value();

// `is` tests the type of the value.
assert!(num.is::<i32>());
assert!(hello.is::<String>());

// `get` tries to get an optional value of the specified type
// and returns an `Err` if the type doesn't match.
assert_eq!(num.get(), Ok(10));
assert!(num.get::<String>().is_err());
assert_eq!(hello.get(), Ok(String::from("Hello!")));
assert_eq!(hello.get::<String>(), Ok(String::from("Hello!")));
assert_eq!(str_none.get::<Option<String>>(), Ok(None));