mirror of
https://github.com/Llewellynvdm/exa.git
synced 2024-09-27 12:49:01 +00:00
420 lines
13 KiB
Rust
420 lines
13 KiB
Rust
#![allow(unused_variables, dead_code)]
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use std::ffi::{OsStr, OsString};
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pub type ShortArg = u8;
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pub type LongArg = &'static str;
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#[derive(PartialEq, Debug)]
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pub enum Flag {
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Short(ShortArg),
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Long(LongArg),
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}
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#[derive(PartialEq, Debug)]
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pub enum Strictness {
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ComplainAboutRedundantArguments,
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UseLastArguments,
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}
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#[derive(Copy, Clone, PartialEq, Debug)]
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pub enum TakesValue {
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Necessary,
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Forbidden,
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}
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#[derive(PartialEq, Debug)]
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pub struct Arg {
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short: Option<ShortArg>,
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long: LongArg,
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takes_value: TakesValue,
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}
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#[derive(PartialEq, Debug)]
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pub struct Args(&'static [Arg]);
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impl Args {
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fn lookup_short<'a>(&self, short: ShortArg) -> Result<&Arg, ParseError<'a>> {
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match self.0.into_iter().find(|arg| arg.short == Some(short)) {
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Some(arg) => Ok(arg),
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None => Err(ParseError::UnknownShortArgument { attempt: short })
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}
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}
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fn lookup_long<'a>(&self, long: &'a OsStr) -> Result<&Arg, ParseError<'a>> {
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match self.0.into_iter().find(|arg| arg.long == long) {
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Some(arg) => Ok(arg),
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None => Err(ParseError::UnknownArgument { attempt: long })
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}
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}
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}
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#[derive(PartialEq, Debug)]
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pub struct Matches<'a> {
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/// Long and short arguments need to be kept in the same vector, because
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/// we usually want the one nearest the end to count.
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flags: Vec<(Flag, Option<&'a OsStr>)>,
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frees: Vec<&'a OsStr>,
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}
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#[derive(PartialEq, Debug)]
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pub enum ParseError<'a> {
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NeedsValue { flag: Flag },
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ForbiddenValue { flag: Flag },
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UnknownShortArgument { attempt: ShortArg },
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UnknownArgument { attempt: &'a OsStr },
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}
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fn parse<'a>(args: Args, inputs: &'a [OsString]) -> Result<Matches<'a>, ParseError<'a>> {
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use std::os::unix::ffi::OsStrExt;
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use self::TakesValue::*;
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let mut parsing = true;
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let mut results = Matches {
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flags: Vec::new(),
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frees: Vec::new(),
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};
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let mut iter = inputs.iter();
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while let Some(arg) = iter.next() {
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let bytes = arg.as_bytes();
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if !parsing {
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results.frees.push(arg)
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}
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else if arg == "--" {
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parsing = false;
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}
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else if bytes.starts_with(b"--") {
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let long_arg_name = OsStr::from_bytes(&bytes[2..]);
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if let Some((before, after)) = split_on_equals(long_arg_name) {
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let arg = args.lookup_long(before)?;
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let flag = Flag::Long(arg.long);
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match arg.takes_value {
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Necessary => results.flags.push((flag, Some(after))),
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Forbidden => return Err(ParseError::ForbiddenValue { flag })
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}
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}
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else {
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let arg = args.lookup_long(long_arg_name)?;
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let flag = Flag::Long(arg.long);
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match arg.takes_value {
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Forbidden => results.flags.push((flag, None)),
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Necessary => {
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if let Some(next_arg) = iter.next() {
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results.flags.push((flag, Some(next_arg)));
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}
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else {
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return Err(ParseError::NeedsValue { flag })
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}
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}
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}
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}
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}
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else if bytes.starts_with(b"-") && arg != "-" {
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let short_arg = OsStr::from_bytes(&bytes[1..]);
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if let Some((before, after)) = split_on_equals(short_arg) {
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let (arg_with_value, other_args) = before.as_bytes().split_last().unwrap();
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for byte in other_args {
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let arg = args.lookup_short(*byte)?;
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let flag = Flag::Short(*byte);
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match arg.takes_value {
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Forbidden => results.flags.push((flag, None)),
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Necessary => return Err(ParseError::NeedsValue { flag })
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}
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}
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let arg = args.lookup_short(*before.as_bytes().last().unwrap())?;
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let flag = Flag::Short(arg.short.unwrap());
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match arg.takes_value {
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Necessary => results.flags.push((flag, Some(after))),
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Forbidden => return Err(ParseError::ForbiddenValue { flag })
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}
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}
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else {
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for (index, byte) in bytes.into_iter().enumerate().skip(1) {
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let arg = args.lookup_short(*byte)?;
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let flag = Flag::Short(*byte);
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match arg.takes_value {
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Forbidden => results.flags.push((flag, None)),
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Necessary => {
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if index < bytes.len() - 1 {
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let remnants = &bytes[index+1 ..];
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results.flags.push((flag, Some(OsStr::from_bytes(remnants))));
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break;
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}
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else if let Some(next_arg) = iter.next() {
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results.flags.push((flag, Some(next_arg)));
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}
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else {
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return Err(ParseError::NeedsValue { flag })
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}
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}
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}
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}
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}
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}
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else {
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results.frees.push(arg)
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}
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}
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Ok(results)
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}
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/// Splits a string on its `=` character, returning the two substrings on
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/// either side. Returns `None` if there’s no equals or a string is missing.
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fn split_on_equals(input: &OsStr) -> Option<(&OsStr, &OsStr)> {
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use std::os::unix::ffi::OsStrExt;
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if let Some(index) = input.as_bytes().iter().position(|elem| *elem == b'=') {
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let (before, after) = input.as_bytes().split_at(index);
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// The after string contains the = that we need to remove.
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if before.len() >= 1 && after.len() >= 2 {
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return Some((OsStr::from_bytes(before),
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OsStr::from_bytes(&after[1..])))
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}
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}
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None
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}
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/// Creates an `OSString` (used in tests)
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#[cfg(test)]
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fn os(input: &'static str) -> OsString {
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let mut os = OsString::new();
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os.push(input);
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os
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}
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#[cfg(test)]
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mod split_test {
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use super::{split_on_equals, os};
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macro_rules! test_split {
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($name:ident: $input:expr => None) => {
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#[test]
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fn $name() {
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assert_eq!(split_on_equals(&os($input)),
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None);
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}
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};
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($name:ident: $input:expr => $before:expr, $after:expr) => {
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#[test]
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fn $name() {
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assert_eq!(split_on_equals(&os($input)),
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Some((&*os($before), &*os($after))));
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}
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};
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}
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test_split!(empty: "" => None);
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test_split!(letter: "a" => None);
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test_split!(just: "=" => None);
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test_split!(intro: "=bbb" => None);
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test_split!(denou: "aaa=" => None);
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test_split!(equals: "aaa=bbb" => "aaa", "bbb");
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test_split!(sort: "--sort=size" => "--sort", "size");
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test_split!(more: "this=that=other" => "this", "that=other");
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}
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#[cfg(test)]
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mod test {
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use super::*;
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static TEST_ARGS: &'static [Arg] = &[
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Arg { short: Some(b'l'), long: "long", takes_value: TakesValue::Forbidden },
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Arg { short: Some(b'v'), long: "verbose", takes_value: TakesValue::Forbidden },
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Arg { short: Some(b'c'), long: "count", takes_value: TakesValue::Necessary }
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];
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#[test]
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fn empty() {
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let bits = [ ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![] }))
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}
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#[test]
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fn filename() {
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let bits = [ os("exa") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![ os("exa").as_os_str() ], flags: vec![] }))
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}
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#[test]
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fn the_dashes_do_nothing() {
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let bits = [ os("--") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![] }))
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}
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#[test]
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fn but_just_one_does() {
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let bits = [ os("-") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![ os("-").as_os_str() ], flags: vec![] }))
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}
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// ----- long args --------
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#[test]
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fn as_filename() {
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let bits = [ os("--"), os("--long") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![os("--long").as_os_str() ], flags: vec![] }))
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}
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#[test]
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fn long() {
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let bits = [ os("--long") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Long("long"), None) ] }))
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}
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#[test]
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fn long_equals() {
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let bits = [ os("--long=equals") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Err(ParseError::ForbiddenValue { flag: Flag::Long("long") }))
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}
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#[test]
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fn no_arg_separate() {
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let bits = [ os("--long"), os("4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![ os("4").as_os_str() ], flags: vec![ (Flag::Long("long"), None) ] }))
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}
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#[test]
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fn two_long_flags() {
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let bits = [ os("--long"), os("--verbose") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Long("long"), None), (Flag::Long("verbose"), None) ] }))
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}
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#[test]
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fn no_arg_given() {
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let bits = [ os("--count") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Err(ParseError::NeedsValue { flag: Flag::Long("count") }))
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}
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#[test]
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fn arg_equals() {
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let bits = [ os("--count=4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Long("count"), Some(os("4").as_os_str())) ] }))
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}
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#[test]
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fn arg_separate() {
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let bits = [ os("--count"), os("4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Long("count"), Some(os("4").as_os_str())) ] }))
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}
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// ----- short args --------
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#[test]
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fn short_as_filename() {
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let bits = [ os("--"), os("-l") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![os("-l").as_os_str() ], flags: vec![] }))
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}
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#[test]
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fn short_long() {
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let bits = [ os("-l") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'l'), None) ] }))
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}
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#[test]
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fn short_long_equals() {
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let bits = [ os("-l=equals") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Err(ParseError::ForbiddenValue { flag: Flag::Short(b'l') }))
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}
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#[test]
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fn short_no_arg_separate() {
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let bits = [ os("-l"), os("4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![ os("4").as_os_str() ], flags: vec![ (Flag::Short(b'l'), None) ] }))
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}
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#[test]
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fn short_no_arg_given() {
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let bits = [ os("-c") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Err(ParseError::NeedsValue { flag: Flag::Short(b'c') }))
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}
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#[test]
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fn short_arg_equals() {
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let bits = [ os("-c=4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'c'), Some(os("4").as_os_str())) ] }))
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}
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#[test]
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fn short_arg_separate() {
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let bits = [ os("-c"), os("4") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'c'), Some(os("4").as_os_str())) ] }))
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}
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#[test]
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fn two_short_flags() {
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let bits = [ os("-lv") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'l'), None), (Flag::Short(b'v'), None) ] }))
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}
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#[test]
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fn two_short_flags_nothing() {
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let bits = [ os("-lctwo") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'l'), None), (Flag::Short(b'c'), Some(os("two").as_os_str())) ] }))
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}
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#[test]
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fn two_short_flags_equals() {
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let bits = [ os("-lc=two") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'l'), None), (Flag::Short(b'c'), Some(os("two").as_os_str())) ] }))
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}
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#[test]
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fn two_short_flags_next() {
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let bits = [ os("-lc"), os("two") ];
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let results = parse(Args(TEST_ARGS), &bits);
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assert_eq!(results, Ok(Matches { frees: vec![], flags: vec![ (Flag::Short(b'l'), None), (Flag::Short(b'c'), Some(os("two").as_os_str())) ] }))
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}
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}
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