nu_cmd_extra/extra/math/
arctanh.rs

1use nu_engine::command_prelude::*;
2
3#[derive(Clone)]
4pub struct MathArcTanH;
5
6impl Command for MathArcTanH {
7    fn name(&self) -> &str {
8        "math arctanh"
9    }
10
11    fn signature(&self) -> Signature {
12        Signature::build("math arctanh")
13            .input_output_types(vec![
14                (Type::Number, Type::Float),
15                (
16                    Type::List(Box::new(Type::Number)),
17                    Type::List(Box::new(Type::Float)),
18                ),
19            ])
20            .allow_variants_without_examples(true)
21            .category(Category::Math)
22    }
23
24    fn description(&self) -> &str {
25        "Returns the inverse of the hyperbolic tangent function."
26    }
27
28    fn search_terms(&self) -> Vec<&str> {
29        vec!["trigonometry", "inverse", "hyperbolic"]
30    }
31
32    fn run(
33        &self,
34        engine_state: &EngineState,
35        _stack: &mut Stack,
36        call: &Call,
37        input: PipelineData,
38    ) -> Result<PipelineData, ShellError> {
39        let head = call.head;
40        // This doesn't match explicit nulls
41        if let PipelineData::Empty = input {
42            return Err(ShellError::PipelineEmpty { dst_span: head });
43        }
44        input.map(move |value| operate(value, head), engine_state.signals())
45    }
46
47    fn examples(&self) -> Vec<Example<'_>> {
48        vec![Example {
49            description: "Get the arctanh of 1",
50            example: "1 | math arctanh",
51            result: Some(Value::test_float(f64::INFINITY)),
52        }]
53    }
54}
55
56fn operate(value: Value, head: Span) -> Value {
57    match value {
58        numeric @ (Value::Int { .. } | Value::Float { .. }) => {
59            let span = numeric.span();
60            let (val, span) = match numeric {
61                Value::Int { val, .. } => (val as f64, span),
62                Value::Float { val, .. } => (val, span),
63                _ => unreachable!(),
64            };
65
66            if (-1.0..=1.0).contains(&val) {
67                let val = val.atanh();
68
69                Value::float(val, span)
70            } else {
71                Value::error(
72                    ShellError::UnsupportedInput {
73                        msg: "'arctanh' undefined for values outside the open interval (-1, 1)."
74                            .into(),
75                        input: "value originates from here".into(),
76                        msg_span: head,
77                        input_span: span,
78                    },
79                    head,
80                )
81            }
82        }
83        Value::Error { .. } => value,
84        other => Value::error(
85            ShellError::OnlySupportsThisInputType {
86                exp_input_type: "numeric".into(),
87                wrong_type: other.get_type().to_string(),
88                dst_span: head,
89                src_span: other.span(),
90            },
91            head,
92        ),
93    }
94}
95
96#[cfg(test)]
97mod test {
98    use super::*;
99
100    #[test]
101    fn test_examples() {
102        use crate::test_examples;
103
104        test_examples(MathArcTanH {})
105    }
106}
nu_cmd_extra/extra/math/arctanh.rs

nu_cmd_extra/extra/math/
arctanh.rs
