IO Arg

Conviniently accept either standard streams or file paths in CLI tools written in Rust as arguments.

Usage

```rust use io_arg::IoArg; use clap::Parser;

/// A command line tool taking a required input argument and an optional output argument.

[derive(Debug, Parser)]

struct Cli { /// Path to input file. Set to "-" to use STDIN instead of a file. input: IoArg, /// Path to output file. Leave out or set to "-" to use STDOUT instead of a file. #[structopt(long, short = "o", default_value = "-")] output: IoArg, } ```