nu_cmd_extra/extra/math/
exp.rs

1use nu_engine::command_prelude::*;
2
3#[derive(Clone)]
4pub struct MathExp;
5
6impl Command for MathExp {
7    fn name(&self) -> &str {
8        "math exp"
9    }
10
11    fn signature(&self) -> Signature {
12        Signature::build("math exp")
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 e raised to the power of x."
26    }
27
28    fn search_terms(&self) -> Vec<&str> {
29        vec!["exponential", "exponentiation", "euler"]
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![
49            Example {
50                description: "Get e raised to the power of zero",
51                example: "0 | math exp",
52                result: Some(Value::test_float(1.0f64)),
53            },
54            Example {
55                description: "Get e (same as 'math e')",
56                example: "1 | math exp",
57                result: Some(Value::test_float(1.0f64.exp())),
58            },
59        ]
60    }
61}
62
63fn operate(value: Value, head: Span) -> Value {
64    match value {
65        numeric @ (Value::Int { .. } | Value::Float { .. }) => {
66            let span = numeric.span();
67            let (val, span) = match numeric {
68                Value::Int { val, .. } => (val as f64, span),
69                Value::Float { val, .. } => (val, span),
70                _ => unreachable!(),
71            };
72
73            Value::float(val.exp(), span)
74        }
75        Value::Error { .. } => value,
76        other => Value::error(
77            ShellError::OnlySupportsThisInputType {
78                exp_input_type: "numeric".into(),
79                wrong_type: other.get_type().to_string(),
80                dst_span: head,
81                src_span: other.span(),
82            },
83            head,
84        ),
85    }
86}
87
88#[cfg(test)]
89mod test {
90    use super::*;
91
92    #[test]
93    fn test_examples() {
94        use crate::test_examples;
95
96        test_examples(MathExp {})
97    }
98}
nu_cmd_extra/extra/math/exp.rs

nu_cmd_extra/extra/math/
exp.rs
