Several ideas about formatting

1

  1. reusable format_template!({string literal}) (how to resolve named parameter needed to be captured?)

  2. delayed format intermediate like chrono::format::DelayedFormat

if using format_args! like this

let s = "abc";
let n = 42;
let x = format_args!("test {s} {n}");
println!("Hello, world! {}", x);

error temporary value dropped while borrowed will be raised.

  1. std::fmt::write_to_string specialization similar to std::fmt::write without std::io::Error
2

Internally, format_args! is constructed in a way that prevents it from being assigned to a variable (it creates temporary arrays that don't live long enough).

3

It's not the temporary arrays that are the issue, it's the function calls blocking lifetime extension of those arrays. I've re-implemented format_args! as a macro but using struct-constructor syntax instead of function calls and it allows this sort of binding just fine.

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