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use crate::Error;
use std::io::Write;
pub const FOUR_SPACES: &str = " ";
pub struct IndentWriter<'a> {
one_indent: String,
current_level: usize,
writer: &'a mut dyn Write,
}
impl<'a> IndentWriter<'a> {
pub fn indent(&mut self) {
self.current_level += 1;
}
pub fn unindent(&mut self) {
if self.current_level == 0 {
panic!("Tried to un-indent past start of line.")
}
self.current_level -= 1;
}
pub fn new(writer: &'a mut dyn Write) -> Self {
Self {
one_indent: FOUR_SPACES.to_string(),
current_level: 0,
writer,
}
}
pub fn with_indent(writer: &'a mut dyn Write, one_indent: &str) -> Self {
Self {
one_indent: one_indent.to_string(),
current_level: 0,
writer,
}
}
pub fn indented(&mut self, f: impl FnOnce(&mut dyn Write) -> std::io::Result<()>) -> Result<(), Error> {
for _ in 0..self.current_level {
write!(&mut self.writer, "{}", self.one_indent)?;
}
f(&mut self.writer)?;
Ok(())
}
pub fn indented_block(&mut self, block: Option<(&str, &str)>, f: impl FnOnce(&mut Self) -> Result<(), Error>) -> Result<(), Error> {
if let Some(block) = block {
self.indented(|w| writeln!(w, "{}", block.0))?;
}
self.indent();
f(self)?;
self.unindent();
if let Some(block) = block {
self.indented(|w| writeln!(w, "{}", block.1))?;
}
Ok(())
}
pub fn writer(&mut self) -> &mut dyn Write {
&mut self.writer
}
pub fn newline(&mut self) -> Result<(), Error> {
writeln!(&mut self.writer)?;
Ok(())
}
}
#[macro_export]
macro_rules! indented {
($w:expr, [ $($i:pat)+ ], $x:expr, $($param:expr),*) => {
{
$(
let $i = ();
$w.indent();
)*
let rval = $w.indented(|w| writeln!(w, $x, $($param),*));
$(
let $i = ();
$w.unindent();
)*
rval
}
};
($w:expr, [ $($i:pat)+ ], $x:expr) => {
{
$(
let $i = ();
$w.indent();
)*
let rval = $w.indented(|w| writeln!(w, $x));
$(
let $i = ();
$w.unindent();
)*
rval
}
};
($w:expr, $x:expr, $($param:expr),*) => {
{
$w.indented(|w| writeln!(w, $x, $($param),*))
}
};
($w:expr, $x:expr) => {
{
$w.indented(|w| writeln!(w, $x))
}
};
}