nushell/crates/nu-command/src/commands/math/round.rs
JT d9d956e54f
Fix issue in external subexpression paths (#3642)
* Fix issue in external subexpression paths

* new clippy dropped

* clippy
2021-06-18 07:59:58 +12:00

113 lines
3.4 KiB
Rust

use crate::prelude::*;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::{Primitive, Signature, SyntaxShape, UntaggedValue, Value};
use nu_source::Tagged;
pub struct SubCommand;
impl WholeStreamCommand for SubCommand {
fn name(&self) -> &str {
"math round"
}
fn signature(&self) -> Signature {
Signature::build("math round").named(
"precision",
SyntaxShape::Number,
"digits of precision",
Some('p'),
)
}
fn usage(&self) -> &str {
"Applies the round function to a list of numbers"
}
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
operate(args)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Apply the round function to a list of numbers",
example: "echo [1.5 2.3 -3.1] | math round",
result: Some(vec![
UntaggedValue::int(2).into(),
UntaggedValue::int(2).into(),
UntaggedValue::int(-3).into(),
]),
},
Example {
description: "Apply the round function with precision specified",
example: "echo [1.555 2.333 -3.111] | math round -p 2",
result: Some(vec![
UntaggedValue::decimal_from_float(1.56, Span::default()).into(),
UntaggedValue::decimal_from_float(2.33, Span::default()).into(),
UntaggedValue::decimal_from_float(-3.11, Span::default()).into(),
]),
},
]
}
}
fn operate(args: CommandArgs) -> Result<OutputStream, ShellError> {
let precision: Option<Tagged<i16>> = args.get_flag("precision")?;
let input = args.input;
let precision = if let Some(precision) = precision {
precision.item
} else {
0
};
let mapped = input.map(move |val| match val.value {
UntaggedValue::Primitive(Primitive::BigInt(val)) => round_big_int(val),
UntaggedValue::Primitive(Primitive::Decimal(val)) => {
round_big_decimal(val, precision.into())
}
UntaggedValue::Primitive(Primitive::Int(val)) => UntaggedValue::int(val).into(),
other => round_default(other),
});
Ok(mapped.into_output_stream())
}
fn round_big_int(val: BigInt) -> Value {
UntaggedValue::big_int(val).into()
}
fn round_big_decimal(val: BigDecimal, precision: i64) -> Value {
if precision > 0 {
UntaggedValue::decimal(val.with_scale(precision + 1).round(precision)).into()
} else {
let rounded = val.with_scale(precision + 1).round(precision).to_i64();
match rounded {
Some(x) => UntaggedValue::int(x).into(),
None => UntaggedValue::Error(ShellError::untagged_runtime_error(
"Number too larger to round to 64-bit int",
))
.into(),
}
}
}
fn round_default(_: UntaggedValue) -> Value {
UntaggedValue::Error(ShellError::unexpected(
"Only numerical values are supported",
))
.into()
}
#[cfg(test)]
mod tests {
use super::ShellError;
use super::SubCommand;
#[test]
fn examples_work_as_expected() -> Result<(), ShellError> {
use crate::examples::test as test_examples;
test_examples(SubCommand {})
}
}