nushell/crates/nu-command/src/random/decimal.rs
2021-12-03 06:26:12 +13:00

117 lines
3.0 KiB
Rust

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, PipelineData, Range, ShellError, Signature, Span, SyntaxShape, Value,
};
use rand::prelude::{thread_rng, Rng};
use std::cmp::Ordering;
#[derive(Clone)]
pub struct SubCommand;
impl Command for SubCommand {
fn name(&self) -> &str {
"random decimal"
}
fn signature(&self) -> Signature {
Signature::build("random decimal")
.optional("range", SyntaxShape::Range, "Range of values")
.category(Category::Random)
}
fn usage(&self) -> &str {
"Generate a random decimal within a range [min..max]"
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
decimal(engine_state, stack, call)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Generate a default decimal value between 0 and 1",
example: "random decimal",
result: None,
},
Example {
description: "Generate a random decimal less than or equal to 500",
example: "random decimal ..500",
result: None,
},
Example {
description: "Generate a random decimal greater than or equal to 100000",
example: "random decimal 100000..",
result: None,
},
Example {
description: "Generate a random decimal between 1.0 and 1.1",
example: "random decimal 1.0..1.1",
result: None,
},
]
}
}
fn decimal(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
) -> Result<PipelineData, ShellError> {
let span = call.head;
let range: Option<Range> = call.opt(engine_state, stack, 0)?;
let (min, max) = if let Some(r) = range {
(r.from.as_float()?, r.to.as_float()?)
} else {
(0.0, 1.0)
};
match min.partial_cmp(&max) {
Some(Ordering::Greater) => Err(ShellError::InvalidRange(
min.to_string(),
max.to_string(),
span,
)),
Some(Ordering::Equal) => Ok(PipelineData::Value(
Value::Float {
val: min,
span: Span::new(64, 64),
},
None,
)),
_ => {
let mut thread_rng = thread_rng();
let result: f64 = thread_rng.gen_range(min..max);
Ok(PipelineData::Value(
Value::Float {
val: result,
span: Span::new(64, 64),
},
None,
))
}
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}