elegance 0.4.0

A pretty-printing library for Rust with a focus on speed and compactness.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

//! Renders text.

use std::{ffi::OsString, io, iter};

/// An output sink for printer.
pub trait Render {
    type Error;

    fn write_str(&mut self, s: &str) -> Result<(), Self::Error>;
    fn write_spaces(&mut self, n: usize) -> Result<(), Self::Error> {
        self.write_str(&" ".repeat(n))
    }
}

impl Render for String {
    type Error = std::convert::Infallible;

    fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
        self.push_str(s);
        Ok(())
    }

    fn write_spaces(&mut self, n: usize) -> Result<(), Self::Error> {
        self.reserve(n);
        self.extend(iter::repeat(' ').take(n));
        Ok(())
    }
}

impl Render for OsString {
    type Error = std::convert::Infallible;

    fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
        self.push(s);
        Ok(())
    }

    fn write_spaces(&mut self, n: usize) -> Result<(), Self::Error> {
        self.reserve(n);
        (0..n).for_each(|_| self.push(" "));
        Ok(())
    }
}

pub struct Io<W: io::Write>(pub W);

impl<W: io::Write> Render for Io<W> {
    type Error = io::Error;

    fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
        self.0.write_all(s.as_bytes())?;
        Ok(())
    }
}