Enum io_arg::IoArg

pub enum IoArg {
    StdStream,
    File(PathBuf),
}

Argument for CLI tools which can either take a file or STDIN/STDOUT.

Caveat: stdin is represented as “-” at the command line. Which means your tool is going to have a hard time operating on a file named “-”.

use structopt::StructOpt;
use io_arg::IoArg;

#[derive(Debug, StructOpt)]
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.
    output: IoArg,
}

Variants

StdStream

Indicates that the IO is connected to stdin/stdout. Represented as a “-” on the command line.

File(PathBuf)

Indicates that the IO is connected to a file. Contains the file path. Just enter a path at the command line.

Implementations

impl IoArg

pub fn is_file(&self) -> bool

Intended for use in an if expression or other situations there a boolean might be more convinient than matching against variants.

Return

true if variant is File. false if variant is StdStream.

pub fn open_as_input(self) -> Result<Input>

Either calls stdin or File::open depending on io_arg.

pub fn open_as_output(self) -> Result<Output>

Either calls stdout or File::create depending on io_arg.

Trait Implementations

impl Debug for IoArg

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

Formats the value using the given formatter.

impl Eq for IoArg

impl FromStr for IoArg

type Err = Infallible

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.

impl PartialEq<IoArg> for IoArg

fn eq(&self, other: &IoArg) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &IoArg) -> bool

This method tests for !=.

impl StructuralEq for IoArg

impl StructuralPartialEq for IoArg