74 lines
1.9 KiB
Rust
74 lines
1.9 KiB
Rust
use std::ffi::OsString;
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use std::str::FromStr;
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use anyhow::anyhow;
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#[derive(thiserror::Error, Debug)]
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pub enum Error {
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/// If this error is returned from argument parsing, help is displayed.
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#[error("help invoked")]
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Help,
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/// If this error is returned from argument parsing, usage is displayed.
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#[error("usage invoked")]
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Usage,
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/// An error with a hint.
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#[error("{err}")]
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WithHint {
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err: anyhow::Error,
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hint: &'static str,
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},
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}
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pub struct Help {
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pub name: &'static str,
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pub description: &'static str,
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pub version: &'static str,
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pub usage: &'static str,
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}
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pub trait Args: Sized {
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fn from_env() -> anyhow::Result<Self> {
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let args: Vec<_> = std::env::args_os().into_iter().skip(1).collect();
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match Self::from_args(args) {
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Ok((opts, unparsed)) => {
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self::finish(unparsed)?;
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Ok(opts)
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}
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Err(err) => Err(err),
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}
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}
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fn from_args(args: Vec<OsString>) -> anyhow::Result<(Self, Vec<OsString>)>;
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}
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pub fn parse_value<T: FromStr>(flag: &str, value: OsString) -> anyhow::Result<T>
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where
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<T as FromStr>::Err: std::error::Error,
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{
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value
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.into_string()
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.map_err(|_| anyhow!("the value specified for '--{}' is not valid unicode", flag))?
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.parse()
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.map_err(|e| anyhow!("invalid value specified for '--{}' ({})", flag, e))
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}
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pub fn format(arg: lexopt::Arg) -> OsString {
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match arg {
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lexopt::Arg::Long(flag) => format!("--{flag}").into(),
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lexopt::Arg::Short(flag) => format!("-{flag}").into(),
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lexopt::Arg::Value(val) => val,
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}
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}
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pub fn finish(unparsed: Vec<OsString>) -> anyhow::Result<()> {
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if let Some(arg) = unparsed.first() {
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return Err(anyhow::anyhow!(
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"unexpected argument `{}`",
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arg.to_string_lossy()
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));
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}
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Ok(())
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}
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