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use proc_macro2::TokenStream;
use quote::{quote, ToTokens};
pub fn fold_quote<F, I, T>(input: impl Iterator<Item = I>, f: F) -> TokenStream
where
F: Fn(I) -> T,
T: ToTokens,
{
input.fold(quote! {}, |acc, x| {
let y = f(x);
quote! { #acc #y }
})
}
pub fn is_unit(v: &syn::Variant) -> bool {
match v.fields {
syn::Fields::Unit => true,
_ => false,
}
}
#[cfg(feature = "debug-with-rustfmt")]
/// Pretty-print the output of proc macro using rustfmt.
pub fn debug_with_rustfmt(input: &TokenStream) {
use std::env;
use std::ffi::OsStr;
use std::io::Write;
use std::process::{Command, Stdio};
let rustfmt_var = env::var_os("RUSTFMT");
let rustfmt = match &rustfmt_var {
Some(rustfmt) => rustfmt,
None => OsStr::new("rustfmt"),
};
let mut child = Command::new(rustfmt)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.spawn()
.expect("Failed to spawn rustfmt in stdio mode");
{
let stdin = child.stdin.as_mut().expect("Failed to get stdin");
stdin
.write_all(format!("{}", input).as_bytes())
.expect("Failed to write to stdin");
}
let rustfmt_output = child.wait_with_output().expect("rustfmt has failed");
eprintln!(
"{}",
String::from_utf8(rustfmt_output.stdout).expect("rustfmt returned non-UTF8 string")
);
}
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