Struct FileOrStdin

pub struct FileOrStdin<T = String> { /* private fields */ }

Wrapper struct to either read in a file or contents from stdin

FileOrStdin can wrap any type that matches the trait bounds for Arg: FromStr and Clone

use std::path::PathBuf;
use clap::Parser;
use clap_stdin::FileOrStdin;

#[derive(Debug, Parser)]
struct Args {
    input: FileOrStdin,
}

if let Ok(args) = Args::try_parse() {
    println!("input={}", args.input.contents()?);
}

$ echo "1 2 3 4" > input.txt
$ cat input.txt | ./example -
1 2 3 4

$ ./example input.txt
1 2 3 4

Implementations

impl<T> FileOrStdin<T>

pub fn is_stdin(&self) -> bool

Was this value read from stdin

pub fn is_file(&self) -> bool

Was this value read from a file (path passed in from argument values)

pub fn filename(&self) -> &str

The value passed to this arg (Either “-” for stdin or a filepath)

pub fn contents(self) -> Result<T, StdinError>

where T: FromStr, <T as FromStr>::Err: Display,

Read the entire contents from the input source, returning T::from_str

pub fn into_reader(self) -> Result<impl Read, StdinError>

Create a reader from the source, to allow user flexibility of how to read and parse (e.g. all at once or in chunks)

use std::io::Read;

use clap_stdin::FileOrStdin;
use clap::Parser;

#[derive(Parser)]
struct Args {
  input: FileOrStdin,
}

let args = Args::parse();
let mut reader = args.input.into_reader()?;
let mut buf = vec![0;8];
reader.read_exact(&mut buf)?;

Trait Implementations

impl<T: Clone> Clone for FileOrStdin<T>

fn clone(&self) -> FileOrStdin<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for FileOrStdin<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> FromStr for FileOrStdin<T>

type Err = StdinError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.