nushell/crates/nu-command/src/math/avg.rs
Ian Manske 7f61cbbfd6
Add Filesize type (#14369)
# Description
Adds a new `Filesize` type so that `FromValue` can be used to convert a
`Value::Filesize` to a `Filesize`. Currently, to extract a filesize from
a `Value` using `FromValue`, you have to extract an `i64` which coerces
`Value::Int`, `Value::Duration`, and `Value::Filesize` to an `i64`.

Having a separate type also allows us to enforce checked math to catch
overflows. Similarly, it allows us to specify other trait
implementations like `Display` in a common place.

# User-Facing Changes
Multiplication with filesizes now error on overflow. Should not be a
breaking change for plugins (i.e., serialization) since `Filesize` is
marked with `serde(transparent)`.

# Tests + Formatting
Updated some tests.
2024-11-29 21:24:17 +00:00

110 lines
3.2 KiB
Rust

use crate::math::{
reducers::{reducer_for, Reduce},
utils::run_with_function,
};
use nu_engine::command_prelude::*;
const NS_PER_SEC: i64 = 1_000_000_000;
#[derive(Clone)]
pub struct SubCommand;
impl Command for SubCommand {
fn name(&self) -> &str {
"math avg"
}
fn signature(&self) -> Signature {
Signature::build("math avg")
.input_output_types(vec![
(Type::List(Box::new(Type::Duration)), Type::Duration),
(Type::Duration, Type::Duration),
(Type::List(Box::new(Type::Filesize)), Type::Filesize),
(Type::Filesize, Type::Filesize),
(Type::List(Box::new(Type::Number)), Type::Number),
(Type::Number, Type::Number),
(Type::Range, Type::Number),
(Type::table(), Type::record()),
(Type::record(), Type::record()),
])
.allow_variants_without_examples(true)
.category(Category::Math)
}
fn description(&self) -> &str {
"Returns the average of a list of numbers."
}
fn search_terms(&self) -> Vec<&str> {
vec!["average", "mean", "statistics"]
}
fn is_const(&self) -> bool {
true
}
fn run(
&self,
_engine_state: &EngineState,
_stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
run_with_function(call, input, average)
}
fn run_const(
&self,
_working_set: &StateWorkingSet,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
run_with_function(call, input, average)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Compute the average of a list of numbers",
example: "[-50 100.0 25] | math avg",
result: Some(Value::test_float(25.0)),
},
Example {
description: "Compute the average of a list of durations",
example: "[2sec 1min] | math avg",
result: Some(Value::test_duration(31 * NS_PER_SEC)),
},
Example {
description: "Compute the average of each column in a table",
example: "[[a b]; [1 2] [3 4]] | math avg",
result: Some(Value::test_record(record! {
"a" => Value::test_int(2),
"b" => Value::test_int(3),
})),
},
]
}
}
pub fn average(values: &[Value], span: Span, head: Span) -> Result<Value, ShellError> {
let sum = reducer_for(Reduce::Summation);
let total = &sum(Value::int(0, head), values.to_vec(), span, head)?;
let span = total.span();
match total {
Value::Filesize { val, .. } => Ok(Value::filesize(val.get() / values.len() as i64, span)),
Value::Duration { val, .. } => Ok(Value::duration(val / values.len() as i64, span)),
_ => total.div(head, &Value::int(values.len() as i64, head), head),
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}