nushell/crates/nu-command/src/random/chars.rs

93 lines
2.1 KiB
Rust

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, SyntaxShape, Value};
use rand::{
distributions::{Alphanumeric, Distribution},
thread_rng,
};
const DEFAULT_CHARS_LENGTH: usize = 25;
#[derive(Clone)]
pub struct SubCommand;
impl Command for SubCommand {
fn name(&self) -> &str {
"random chars"
}
fn signature(&self) -> Signature {
Signature::build("random chars")
.named("length", SyntaxShape::Int, "Number of chars", Some('l'))
.category(Category::Random)
}
fn usage(&self) -> &str {
"Generate random chars"
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
chars(engine_state, stack, call)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Generate random chars",
example: "random chars",
result: None,
},
Example {
description: "Generate random chars with specified length",
example: "random chars -l 20",
result: None,
},
]
}
}
fn chars(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
) -> Result<PipelineData, ShellError> {
let span = call.head;
let length: Option<usize> = call.get_flag(engine_state, stack, "length")?;
let chars_length = length.unwrap_or(DEFAULT_CHARS_LENGTH);
let mut rng = thread_rng();
let random_string = Alphanumeric
.sample_iter(&mut rng)
.take(chars_length)
.map(char::from)
.collect::<String>();
Ok(PipelineData::Value(
Value::String {
val: random_string,
span,
},
None,
))
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}