rhaj/rhai_engine/rhaibook/rust/print-custom.md

Printing for Custom Types

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Provide These Functions

To use [custom types] for [print] and [debug], or convert a [custom type] into a [string], it is necessary that the following functions, at minimum, be registered (assuming the [custom type] is T: Display + Debug).

Function	Signature	Typical implementation	Usage
to_string	|x: &mut T| -> String	x.to_string()	converts the [custom type] into a [string]
to_debug	|x: &mut T| -> String	format!("{x:?}")	converts the [custom type] into a [string] in debug format

If these functions are defined via a [plugin module], be sure to include the `#[rhai_fn(global)]` attribute
in order to make them available globally.

See [this section]({{rootUrl}}/plugins/module.md#use-rhai_fnglobal) for more details.

Also Consider These

The following functions are implemented using to_string or to_debug by default, but can be overloaded with custom versions.

Function	Signature	Default	Usage
print	|x: &mut T| -> String	to_string	converts the [custom type] into a [string] for the [print] statement
debug	|x: &mut T| -> String	to_debug	converts the [custom type] into a [string] for the [debug] statement
+ operator	|s: &str, x: T| -> String	to_string	concatenates the [custom type] with another [string]
+ operator	|x: &mut T, s: &str| -> String	to_string	concatenates another [string] with the [custom type]
+= operator	|s: &mut ImmutableString, x: T|	to_string	appends the [custom type] to an existing [string]