Function from_fn

pub fn from_fn<F, L>(f: F) -> FromFn<F>
where
    F: FnOnce(&mut Tokens<L>),
    L: Lang,

Construct a FormatInto implementation from a function.

Examples

use genco::{quote, quote_in};
use genco::lang::{Lang, Rust};
use genco::tokens::{ItemStr, FormatInto, Tokens, from_fn, static_literal};

fn comment(s: impl Into<ItemStr> + Copy) -> impl FormatInto<Rust> + Copy {
    from_fn(move |tokens| {
        let s = s.into();
        quote_in!(*tokens => $(static_literal("//")) #s);
    })
}

let c = comment("hello world");
let _: Tokens<Rust> = quote!($c $['\n'] $c);