nushell/src/plugins/skip.rs

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use indexmap::IndexMap;
use nu::{
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serve_plugin, Args, CommandConfig, Plugin, Primitive, ReturnSuccess, ReturnValue, ShellError,
Spanned, Value,
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};
struct NewSkip {
skip_amount: i64,
}
impl NewSkip {
fn new() -> NewSkip {
NewSkip { skip_amount: 0 }
}
}
impl Plugin for NewSkip {
fn config(&mut self) -> Result<CommandConfig, ShellError> {
Ok(CommandConfig {
name: "skip".to_string(),
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positional: vec![],
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is_filter: true,
is_sink: false,
named: IndexMap::new(),
rest_positional: true,
})
}
fn begin_filter(&mut self, args: Args) -> Result<(), ShellError> {
if let Some(args) = args.positional {
for arg in args {
match arg {
Spanned {
item: Value::Primitive(Primitive::Int(i)),
..
} => {
self.skip_amount = i;
}
_ => return Err(ShellError::labeled_error("Unrecognized type in params", "expected an integer", arg.span)),
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}
}
}
Ok(())
}
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fn filter(&mut self, input: Spanned<Value>) -> Result<Vec<ReturnValue>, ShellError> {
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if self.skip_amount == 0 {
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Ok(vec![ReturnSuccess::value(input)])
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} else {
self.skip_amount -= 1;
Ok(vec![])
}
}
}
fn main() {
serve_plugin(&mut NewSkip::new());
}