aoc_utils/
args.rs

1use std::path::PathBuf;
2
3use crate::bufwrap::{file_reader, stdin_reader, BufferedInput};
4
5use clap::{value_parser, Arg, Command};
6
7/// CLI command that provides an input source to an AOC problem.
8///
9/// Supports input from a given file as well as from STDIN.
10/// Implements `std::io::BufRead` for the convenience of the `BufRead::lines` iterator.
11///
12/// # Example
13///
14/// If your executable is named `prog` and the description is "Example description",
15/// then the help (`prog --help`) will look like this:
16///
17/// ```console
18/// Example description
19///
20/// USAGE:
21///     prog [FILE]
22///
23/// FLAGS:
24///     -h, --help       Prints help information
25///     -V, --version    Prints version information
26///
27/// ARGS:
28///     <FILE>    Input file (defaults to STDIN if not provided)
29/// ```
30pub struct AocCommand {
31    description: String,
32}
33
34impl AocCommand {
35    /// Returns this struct with the description configured.
36    ///
37    /// # Arguments
38    ///
39    /// * `description` - provides an "about" section in the usage manual.
40    pub fn new(description: &str) -> Self {
41        Self {
42            description: description.to_string(),
43        }
44    }
45
46    /// Parse cmdline arguments and create a new object
47    /// to read lines from an arbitrary input source.
48    ///
49    /// The application optionally expects a path argument
50    /// that specifies the file to read from.
51    /// If not present, the input is read from STDIN.
52    ///
53    /// # Example
54    ///
55    /// ```
56    /// use std::io::BufRead;
57    /// use aoc_utils::AocCommand;
58    ///
59    /// let input = AocCommand::new("Example solution").parse_args().unwrap();
60    /// let lines: Vec<String> = input.lines().map(Result::unwrap).collect();
61    /// ```
62    pub fn parse_args(&self) -> std::io::Result<BufferedInput> {
63        let input_arg = Arg::new("input")
64            .value_parser(value_parser!(PathBuf))
65            .value_name("FILE")
66            .help("Input file (defaults to STDIN if not provided)");
67        let app = Command::new("").about(&self.description).arg(input_arg);
68
69        let matches = app.get_matches();
70
71        let result = match matches.get_one::<PathBuf>("input") {
72            Some(path) => BufferedInput::File(file_reader(path)?),
73            _ => BufferedInput::Stdin(stdin_reader()),
74        };
75
76        Ok(result)
77    }
78}
aoc_utils/args.rs

aoc_utils/
args.rs
