use std::cell::RefCell;
use std::fmt;
pub struct DebugMap<F>(pub F);
impl<F, I, K, V> fmt::Debug for DebugMap<F>
where
F: Fn() -> I,
I: IntoIterator<Item = (K, V)>,
K: fmt::Debug,
V: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_map().entries((self.0)()).finish()
}
}
pub struct NoPretty<T>(pub T);
impl<T> fmt::Debug for NoPretty<T>
where
T: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?}", self.0)
}
}
#[derive(Clone)]
pub struct Format<'a, I> {
sep: &'a str,
inner: RefCell<Option<I>>,
}
pub trait IterFormatExt: Iterator {
fn format(self, separator: &str) -> Format<Self>
where
Self: Sized,
{
Format {
sep: separator,
inner: RefCell::new(Some(self)),
}
}
}
impl<I> IterFormatExt for I where I: Iterator {}
impl<'a, I> Format<'a, I>
where
I: Iterator,
{
fn format<F>(&self, f: &mut fmt::Formatter, mut cb: F) -> fmt::Result
where
F: FnMut(&I::Item, &mut fmt::Formatter) -> fmt::Result,
{
let mut iter = match self.inner.borrow_mut().take() {
Some(t) => t,
None => panic!("Format: was already formatted once"),
};
if let Some(fst) = iter.next() {
cb(&fst, f)?;
for elt in iter {
if !self.sep.is_empty() {
f.write_str(self.sep)?;
}
cb(&elt, f)?;
}
}
Ok(())
}
}
macro_rules! impl_format {
($($fmt_trait:ident)*) => {
$(
impl<'a, I> fmt::$fmt_trait for Format<'a, I>
where I: Iterator,
I::Item: fmt::$fmt_trait,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.format(f, fmt::$fmt_trait::fmt)
}
}
)*
}
}
impl_format!(Debug);