rhai/doc/src/rust/print-custom.md

Printing for Custom Types

{{#include ../links.md}}

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

Function	Signature	Typical implementation	Usage
to_string	|s: &mut T| -> ImmutableString	s.to_string().into()	converts the custom type into a [string]
print	|s: &mut T| -> ImmutableString	s.to_string().into()	converts the custom type into a [string] for the [print] statement
debug	|s: &mut T| -> ImmutableString	format!("{:?}", s).into()	converts the custom type into a [string] for the [debug] statement
+	|s1: ImmutableString, s: T| -> ImmutableString	s1 + s	appends the custom type to another [string], for print("Answer: " + type); usage
+	|s: T, s2: ImmutableString| -> ImmutableString	s.to_string().push_str(&s2).into();	appends another [string] to the custom type, for print(type + " is the answer"); usage
+=	|s1: &mut ImmutableString, s: T|	s1 += s.to_string()	appends the custom type to an existing [string], for s += type; usage