Helpers for Advent of Code

This crate contains some helper methods that I regularly use in my Advent of Code solutions.

Processing of command line arguments

args::get_args

Reads the command line arguments and checks whether the correct number of arguments are present.

Example

use rdcl_aoc_helpers::args::get_args;

fn example1() {
    let args = get_args(&["<input file>", "<init>"], 1);
    println!("{:?}", args);
}

fn example2() {
    let args = get_args_repeating(&["<input file>", "<x1> ... <xn>"], 1);
    println!("{:?}", args);
}

Error handling

error::WithOrExit

This trait adds a or_exit_with method. The purpose of this method, is to allow you to easily let your program terminate with a specific exit code. It has been implemented for Result and Option. The implementation for Result requires that the associated error type implements fmt::Debug.

Example

use rdcl_aoc_helpers::error::WithOrExit;

fn main() {
    some_operation_that_returns_a_result()
        .or_exit_with(25);
}

error::ParseError

A generic error containing just a message. It implements fmt::Display and fmt::Debug, and it can be converted from io::Error and num::ParseIntError.

Example

use rdcl_aoc_helpers::error::ParseError;

fn example_with_params(param: u8) -> Result<(), ParseError> {
    if process(param) {
        Ok(())
    } else {
        Err(ParseError(format!("Failed to process param: {}", param)))
    }
}

fn example_without_params() -> Result<(), ParseError> {
    if process() {
        Ok(())
    } else {
        Err(ParseError.of("Failed to process"))
    }
}

I/O operations

input::MultilineFromStr

This trait is inspired by the str::FromStr trait, and allows you to parse input where data might span several lines.

Example

use rdcl_aoc_helpers::error::ParseError;
use rdcl_aoc_helpers::input::MultilineFromStr;

pub struct Record {
    items: Vec<u8>,
}

impl MultilineFromStr for Record {
    type Err = ParseError;

    fn new() -> Self {
        Record {
            items: Vec::new(),
        }
    }

    fn indicates_new_record(&self, line: &str) -> bool {
        line.is_empty()
    }

    fn parse(&mut self, line: &str) -> Result<(), Self::Err> {
        if !line.is_empty() {
            self.items.push(line.parse::<u8>()?);
        }

        Ok(())
    }
}

input::WithReadLines

This trait adds a read_lines method. The purpose of this method is to read the lines from some source (e.g. a file), and then convert each line to a specific type. As an argument, this method takes an exit code that should be used if processing the source fails, and it returns an iterator. This trait has been implemented for fs::File.

Example

use rdcl_aoc_helpers::input::WithReadLines;

fn main() {
    for item in File::open("./my-file.txt").read_lines::<u8>(1) {
        println!("Item: {}", item);
    }
}

input::WithReadMultiLines

This trait adds a read_multi_lines method. It's the equivalent of input::WithReadLines, but rather than depending on str::FromStr, it depends on input::MultilineFromStr.

Example

use rdcl_aoc_helpers::input::WithReadMultiLines;

fn main() {
    for record in File::open("./my-file.txt").read_multi_lines::<Record>(1) {
        println!("Item: {:?}", record);
    }
}

#[derive(Debug)]
struct Record { /* ... */ }
impl MultilineFromStr for Record { /* ... */ }

input::WithAsRecords & input::WithAsMultilineRecords

These traits allow you to easily convert an object to a vec of items of the required type.

Example

#[cfg(test)]
mod tests {
    use rdcl_aoc_helpers::input::WithAsRecords;
    use rdcl_aoc_helpers::input::WithAsMultilineRecords;

    use super::*;

    #[test]
    fn test_simple() {
        let input = vec!["1", "2", "3", "4", "5"]
            .as_records::<u8>()
            .unwrap();

        assert_eq!(input, vec![1, 2, 3, 4, 5]);
    }

    #[test]
    fn test_multiline() {
        let input = vec!["1", "2", "", "3", "4", "", "5"]
            .as_multiline_records::<Record>()
            .unwrap();

        assert_eq!(
            input,
            vec![
                Record { items: vec![1, 2] },
                Record { items: vec![3, 4] },
                Record { items: vec![5] },
            ]
        );
    }
}

Parts

part::Part

This enum is useful if you need to explicitly refer to a part. It implemts str::FromStr and fmt::Display, so you can easily convert to and from a string.

Example

use rdcl_aoc_helpers::part::Part;

fn main() {
    let part = "part 1".parse::<Part>().unwrap();
    println!("[{}] ...", part); // outputs "[part 1] ..."

    let part = Part::Two;
    println!("[{}] ...", part); // outputs "[part 2] ..."
}