How can I implement how a custom rust type is displayed?

[IllustratedMan-code]

After implementing std::fmt::display and std::fmt::debug as well as deriving Steel on my struct, the repl still only displays the struct name, i.e (#project::mystruct::MyStruct). The output of (print mystruct) is the same. How can I control the display/how it is printed?

[mattwparas]

You'll have to implement Custom yourself and implement the fmt function, instead of using the derive:

impl Custom for FunctionSignatureMetadata {
    fn fmt(&self) -> Option<std::result::Result<String, std::fmt::Error>> {
        Some(Ok(format!(
            "(FunctionSignatureMetadata #:name {} #:arity {:?} #:const? {})",
            self.name, self.arity, self.is_const
        )))
    }
}