2 unstable releases
0.2.0 | Mar 17, 2024 |
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0.1.1 | Aug 12, 2021 |
0.1.0 |
|
#6 in #builtins
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Used in 2 crates
(via bash-builtins)
22KB
415 lines
bash-builtins
A Rust crate to provide utilities to implement loadable builtins for bash.
See the API documentation for a detailed explanation on how to use this crate.
Example
See the examples
directory for more examples.
//! Bash builtin to implement a counter.
use bash_builtins::{builtin_metadata, Args, Builtin, BuiltinOptions, Result};
use std::io::{stdout, Write};
builtin_metadata!(
name = "counter",
create = Counter::default,
short_doc = "counter [-r] [-s value] [-a value]",
long_doc = "
Print a value, and increment it.
Options:
-r\tReset the value to 0.
-s\tSet the counter to a specific value.
-a\tIncrement the counter by a value.
",
);
#[derive(BuiltinOptions)]
enum Opt {
#[opt = 'r']
Reset,
#[opt = 's']
Set(isize),
#[opt = 'a']
Add(isize),
}
#[derive(Default)]
struct Counter(isize);
impl Builtin for Counter {
fn call(&mut self, args: &mut Args) -> Result<()> {
// No options: print the current value and increment it.
if args.is_empty() {
// Use writeln!() instead of println!() to avoid
// panicking if stdout is closed.
writeln!(stdout(), "{}", self.0)?;
self.0 += 1;
return Ok(());
}
// Parse options. They can change the value of the counter, but the
// updated value is stored only if we don't get any error.
let mut value = self.0;
for opt in args.options() {
match opt? {
Opt::Reset => value = 0,
Opt::Set(v) => value = v,
Opt::Add(v) => value += v,
}
}
// It is an error if we receive free arguments.
args.finished()?;
// Update the state and exit.
self.0 = value;
Ok(())
}
}
License
This crate is released under the terms of Apache License 2.0, which is compatible with GPLv3.
See https://www.apache.org/licenses/GPL-compatibility.html for more information about the compatibility.
Dependencies
~1.5MB
~36K SLoC