2021-09-29 20:25:05 +02:00
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use nu_protocol::ast::Call;
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use nu_protocol::engine::{Command, EvaluationContext};
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2021-10-25 06:01:02 +02:00
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use nu_protocol::{IntoPipelineData, PipelineData, Signature, Value};
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2021-09-29 20:25:05 +02:00
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2021-10-25 06:01:02 +02:00
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#[derive(Clone)]
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2021-09-29 20:25:05 +02:00
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pub struct Length;
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impl Command for Length {
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fn name(&self) -> &str {
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"length"
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}
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fn usage(&self) -> &str {
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"Count the number of elements in the input."
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}
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fn signature(&self) -> nu_protocol::Signature {
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Signature::build("length")
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}
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fn run(
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&self,
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_context: &EvaluationContext,
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call: &Call,
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input: PipelineData,
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) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
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match input {
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PipelineData::Value(Value::Nothing { .. }) => Ok(Value::Int {
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val: 0,
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span: call.head,
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}
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.into_pipeline_data()),
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_ => Ok(Value::Int {
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val: input.count() as i64,
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span: call.head,
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}
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.into_pipeline_data()),
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}
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}
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}
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