Using pass-through formatting in Display

[nyurik]

Is there a way to generate this Display implementation? Note that this is not a write!(f, "{0}", v), but rather v.fmt(f) call.

use std::fmt;

pub enum Term {
    Int(i32),
    Float(f64),
    Str(String),
}

impl fmt::Display for Term {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Int(v) => v.fmt(f),
            Self::Float(v) => v.fmt(f),
            Self::Str(v) => v.fmt(f),
        }
    }
}

[frozenlib]

Currently, parse-display does not have the ability to generate such code.

In the future, we may add the ability to generate such code by specifying an attribute such as #[display(transparent)].

[nyurik]

Thx @frozenlib for quick reply! Could you maybe point me to what changes would be needed to make it possible? I could try to hack on it in my spare time

[frozenlib]

parse-display/parse-display-derive/src/lib.rs

Lines 750 to 759 in 1edea8e

	struct DisplayArgs {
	#[struct_meta(unnamed)]
	format: Option<LitStr>,
	with: Option<Expr>,
	style: Option<LitStr>,
	bound: Option<Vec<Quotable<Bound>>>,
	#[struct_meta(name = "crate")]
	crate_path: Option<Path>,
	dump: bool,
	}

I think the first step would be to add field transparent to DisplayArgs and change the code generation method to use this value.

I won't know until I actually write it, but it seems like many modifications will be necessary.