nushell/crates/nu-command/src/strings/str_/reverse.rs

101 lines
2.8 KiB
Rust

use crate::input_handler::{operate, CellPathOnlyArgs};
use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::ast::CellPath;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::Category;
use nu_protocol::{Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value};
#[derive(Clone)]
pub struct SubCommand;
impl Command for SubCommand {
fn name(&self) -> &str {
"str reverse"
}
fn signature(&self) -> Signature {
Signature::build("str reverse")
.input_output_types(vec![(Type::String, Type::String)])
.vectorizes_over_list(true)
.rest(
"rest",
SyntaxShape::CellPath,
"For a data structure input, reverse strings at the given cell paths",
)
.category(Category::Strings)
}
fn usage(&self) -> &str {
"Reverse every string in the pipeline"
}
fn search_terms(&self) -> Vec<&str> {
vec!["convert", "inverse", "flip"]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let cell_paths: Vec<CellPath> = call.rest(engine_state, stack, 0)?;
let args = CellPathOnlyArgs::from(cell_paths);
operate(action, args, input, call.head, engine_state.ctrlc.clone())
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Reverse a single string",
example: "'Nushell' | str reverse",
result: Some(Value::test_string("llehsuN")),
},
Example {
description: "Reverse multiple strings in a list",
example: "['Nushell' 'is' 'cool'] | str reverse",
result: Some(Value::List {
vals: vec![
Value::test_string("llehsuN"),
Value::test_string("si"),
Value::test_string("looc"),
],
span: Span::test_data(),
}),
},
]
}
}
fn action(input: &Value, _arg: &CellPathOnlyArgs, head: Span) -> Value {
match input {
Value::String { val, .. } => Value::String {
val: val.chars().rev().collect::<String>(),
span: head,
},
Value::Error { .. } => input.clone(),
_ => Value::Error {
error: ShellError::OnlySupportsThisInputType(
"string".into(),
input.get_type().to_string(),
head,
input.expect_span(),
),
},
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}