nu_command/math/
sqrt.rs

1use crate::math::utils::ensure_bounded;
2use nu_engine::command_prelude::*;
3
4#[derive(Clone)]
5pub struct MathSqrt;
6
7impl Command for MathSqrt {
8    fn name(&self) -> &str {
9        "math sqrt"
10    }
11
12    fn signature(&self) -> Signature {
13        Signature::build("math sqrt")
14            .input_output_types(vec![
15                (Type::Number, Type::Float),
16                (
17                    Type::List(Box::new(Type::Number)),
18                    Type::List(Box::new(Type::Float)),
19                ),
20                (Type::Range, Type::List(Box::new(Type::Number))),
21            ])
22            .allow_variants_without_examples(true)
23            .category(Category::Math)
24    }
25
26    fn description(&self) -> &str {
27        "Returns the square root of the input number."
28    }
29
30    fn search_terms(&self) -> Vec<&str> {
31        vec!["square", "root"]
32    }
33
34    fn is_const(&self) -> bool {
35        true
36    }
37
38    fn run(
39        &self,
40        engine_state: &EngineState,
41        _stack: &mut Stack,
42        call: &Call,
43        input: PipelineData,
44    ) -> Result<PipelineData, ShellError> {
45        let head = call.head;
46        // This doesn't match explicit nulls
47        if matches!(input, PipelineData::Empty) {
48            return Err(ShellError::PipelineEmpty { dst_span: head });
49        }
50        if let PipelineData::Value(
51            Value::Range {
52                ref val,
53                internal_span,
54            },
55            ..,
56        ) = input
57        {
58            ensure_bounded(val.as_ref(), internal_span, head)?;
59        }
60        input.map(move |value| operate(value, head), engine_state.signals())
61    }
62
63    fn run_const(
64        &self,
65        working_set: &StateWorkingSet,
66        call: &Call,
67        input: PipelineData,
68    ) -> Result<PipelineData, ShellError> {
69        let head = call.head;
70        // This doesn't match explicit nulls
71        if matches!(input, PipelineData::Empty) {
72            return Err(ShellError::PipelineEmpty { dst_span: head });
73        }
74        if let PipelineData::Value(
75            Value::Range {
76                ref val,
77                internal_span,
78            },
79            ..,
80        ) = input
81        {
82            ensure_bounded(val.as_ref(), internal_span, head)?;
83        }
84        input.map(
85            move |value| operate(value, head),
86            working_set.permanent().signals(),
87        )
88    }
89
90    fn examples(&self) -> Vec<Example> {
91        vec![Example {
92            description: "Compute the square root of each number in a list",
93            example: "[9 16] | math sqrt",
94            result: Some(Value::list(
95                vec![Value::test_float(3.0), Value::test_float(4.0)],
96                Span::test_data(),
97            )),
98        }]
99    }
100}
101
102fn operate(value: Value, head: Span) -> Value {
103    let span = value.span();
104    match value {
105        Value::Int { val, .. } => {
106            let squared = (val as f64).sqrt();
107            if squared.is_nan() {
108                return error_negative_sqrt(head, span);
109            }
110            Value::float(squared, span)
111        }
112        Value::Float { val, .. } => {
113            let squared = val.sqrt();
114            if squared.is_nan() {
115                return error_negative_sqrt(head, span);
116            }
117            Value::float(squared, span)
118        }
119        Value::Error { .. } => value,
120        other => Value::error(
121            ShellError::OnlySupportsThisInputType {
122                exp_input_type: "numeric".into(),
123                wrong_type: other.get_type().to_string(),
124                dst_span: head,
125                src_span: other.span(),
126            },
127            head,
128        ),
129    }
130}
131
132fn error_negative_sqrt(head: Span, span: Span) -> Value {
133    Value::error(
134        ShellError::UnsupportedInput {
135            msg: String::from("Can't square root a negative number"),
136            input: "value originates from here".into(),
137            msg_span: head,
138            input_span: span,
139        },
140        span,
141    )
142}
143
144#[cfg(test)]
145mod test {
146    use super::*;
147
148    #[test]
149    fn test_examples() {
150        use crate::test_examples;
151
152        test_examples(MathSqrt {})
153    }
154}
nu_command/math/sqrt.rs

nu_command/math/
sqrt.rs
