forked from extern/nushell
123 lines
3.3 KiB
Rust
123 lines
3.3 KiB
Rust
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use nu_engine::CallExt;
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use nu_protocol::ast::Call;
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use nu_protocol::engine::{Command, EngineState, Stack};
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use nu_protocol::{
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Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Span,
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SyntaxShape, Value,
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};
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#[derive(Clone)]
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pub struct Prepend;
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impl Command for Prepend {
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fn name(&self) -> &str {
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"prepend"
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}
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fn signature(&self) -> nu_protocol::Signature {
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Signature::build("prepend")
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.required("row", SyntaxShape::Any, "the row to prepend")
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.category(Category::Filters)
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}
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fn usage(&self) -> &str {
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"Prepend a row to the table."
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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example: "[1,2,3,4] | prepend 0",
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description: "Prepend one Int item",
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result: Some(Value::List {
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vals: vec![
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Value::test_int(0),
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Value::test_int(1),
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Value::test_int(2),
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Value::test_int(3),
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Value::test_int(4),
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],
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span: Span::unknown(),
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}),
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},
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Example {
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example: "[2,3,4] | prepend [0,1]",
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description: "Prepend two Int items",
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result: Some(Value::List {
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vals: vec![
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Value::test_int(0),
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Value::test_int(1),
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Value::test_int(2),
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Value::test_int(3),
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Value::test_int(4),
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],
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span: Span::unknown(),
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}),
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},
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Example {
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example: "[2,nu,4,shell] | prepend [0,1,rocks]",
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description: "Prepend Ints and Strings",
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result: Some(Value::List {
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vals: vec![
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Value::test_int(0),
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Value::test_int(1),
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Value::test_string("rocks"),
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Value::test_int(2),
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Value::test_string("nu"),
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Value::test_int(4),
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Value::test_string("shell"),
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],
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span: Span::unknown(),
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}),
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},
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]
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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let val: Value = call.req(engine_state, stack, 0)?;
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let vec: Vec<Value> = process_value(val);
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Ok(vec
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.into_iter()
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.chain(input)
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.into_iter()
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.into_pipeline_data(engine_state.ctrlc.clone()))
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}
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}
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fn process_value(val: Value) -> Vec<Value> {
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match val {
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Value::List {
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vals: input_vals,
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span: _,
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} => {
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let mut output = vec![];
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for input_val in input_vals {
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output.push(input_val);
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}
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output
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}
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_ => {
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vec![val]
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}
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}
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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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#[test]
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fn test_examples() {
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use crate::test_examples;
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test_examples(Prepend {})
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}
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}
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