use nu_engine::{eval_block, CallExt};
use nu_protocol::{
ast::Call,
engine::{Closure, Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature,
SyntaxShape, Type, Value,
};
#[derive(Clone)]
pub struct TakeUntil;
impl Command for TakeUntil {
fn name(&self) -> &str {
"take until"
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.input_output_types(vec![
(Type::Table(vec![]), Type::Table(vec![])),
(
Type::List(Box::new(Type::Any)),
Type::List(Box::new(Type::Any)),
),
])
.required(
"predicate",
SyntaxShape::Closure(Some(vec![SyntaxShape::Any, SyntaxShape::Int])),
"The predicate that element(s) must not match.",
)
.category(Category::Filters)
}
fn usage(&self) -> &str {
"Take elements of the input until a predicate is true."
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Take until the element is positive",
example: "[-1 -2 9 1] | take until {|x| $x > 0 }",
result: Some(Value::test_list(vec![
Value::test_int(-1),
Value::test_int(-2),
])),
},
Example {
description: "Take until the element is positive using stored condition",
example: "let cond = {|x| $x > 0 }; [-1 -2 9 1] | take until $cond",
result: Some(Value::test_list(vec![
Value::test_int(-1),
Value::test_int(-2),
])),
},
Example {
description: "Take until the field value is positive",
example: "[{a: -1} {a: -2} {a: 9} {a: 1}] | take until {|x| $x.a > 0 }",
result: Some(Value::test_list(vec![
Value::test_record(record! {
"a" => Value::test_int(-1),
}),
Value::test_record(record! {
"a" => Value::test_int(-2),
}),
])),
},
]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let metadata = input.metadata();
let span = call.head;
let capture_block: Closure = call.req(engine_state, stack, 0)?;
let block = engine_state.get_block(capture_block.block_id).clone();
let var_id = block.signature.get_positional(0).and_then(|arg| arg.var_id);
let mut stack = stack.captures_to_stack(capture_block.captures);
let ctrlc = engine_state.ctrlc.clone();
let engine_state = engine_state.clone();
let redirect_stdout = call.redirect_stdout;
let redirect_stderr = call.redirect_stderr;
Ok(input
.into_iter_strict(span)?
.take_while(move |value| {
if let Some(var_id) = var_id {
stack.add_var(var_id, value.clone());
}
!eval_block(
&engine_state,
&mut stack,
&block,
PipelineData::empty(),
redirect_stdout,
redirect_stderr,
)
.map_or(false, |pipeline_data| {
pipeline_data.into_value(span).is_true()
})
})
.into_pipeline_data_with_metadata(metadata, ctrlc))
}
}
#[cfg(test)]
mod tests {
use crate::TakeUntil;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(TakeUntil)
}
}