inform

indent formatting, everywhere

inform gives you

• A std::fmt::Formatter drop-in replacement designed for formatting structured data such as AST nodes.
• More generally, an API for formatting any type implementing std::io::Write or std::fmt::Write with indentation.

The format and I/O implementations are behind Cargo features "fmt" and "io" respectively, both of which are enabled by default.

Contents

• Examples
• Projects using inform
• Alternatives
• License

Examples

Here's how you can use fmt::IndentFormatter:

use std::fmt::{self, Write};
use inform::common::IndentWriterCommon, fmt::IndentFormatter;

struct TestIndentFormatter;

impl fmt::Display for TestIndentFormatter {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut f = IndentFormatter::new(f, 2);
        writeln!(f, "hello\ngoodbye")?;
        f.increase_indent();
        writeln!(f, "hello\ngoodbye")?;
        f.decrease_indent();
        writeln!(f, "hello\ngoodbye")
    }
}

#[test]
fn test_indent_formatter() {
    assert_eq!(
        "hello\ngoodbye\n  hello\n  goodbye\nhello\ngoodbye\n",
        TestIndentFormatter.to_string()
    );
}

Here's how you can use fmt::IndentWriter:

use std::fmt::{self, Write};
use inform::common::IndentWriterCommon, fmt::IndentWriter;

fn write_text(str: &mut String) -> fmt::Result {
    let mut f = IndentWriter::new(str, 2);
    writeln!(f, "hello\ngoodbye")?;
    f.increase_indent();
    writeln!(f, "hello\ngoodbye")?;
    f.decrease_indent();
    writeln!(f, "hello\ngoodbye")
}

#[test]
fn test_indent_writer() {
    let mut buffer = String::new();
    write_text(&mut buffer).expect("failed to format");
    assert_eq!(
        "hello\ngoodbye\n  hello\n  goodbye\nhello\ngoodbye\n",
        buffer
    );
}

Projects using inform

• calyx-writer
• spadefmt
• pulsar

Alternatives

The following crates are alternatives that I found did not fit my use case.

• https://crates.io/crates/indent
• https://crates.io/crates/indenter
• https://crates.io/crates/indentation
• https://docs.rs/indent_write/latest/indent_write/index.html

License

A copy of the LGPL License is provided in the LICENSE file.