Add inverse for trigonometric functions (#7258)

- `math arcsin`
- `math arccos`
- `math arctan`

Again include `--degrees` or `-d` for convenient output in degrees

crates/nu-command/src/default_context.rs

@@ -411,6 +411,9 @@ pub fn create_default_context() -> EngineState {
             MathSinH,
             MathCosH,
             MathTanH,
+            MathArcSin,
+            MathArcCos,
+            MathArcTan,
             MathPi,
             MathEuler,
         };

crates/nu-command/src/math/arccos.rs

@@ -0,0 +1,105 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Span, Type, Value};
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "math arccos"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("math arccos")
+            .switch("degrees", "Return degrees instead of radians", Some('d'))
+            .input_output_types(vec![(Type::Number, Type::Float)])
+            .vectorizes_over_list(true)
+            .category(Category::Math)
+    }
+
+    fn usage(&self) -> &str {
+        "Returns the arccosine of the number."
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["trigonometry", "inverse"]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        let head = call.head;
+        let use_degrees = call.has_flag("degrees");
+        input.map(
+            move |value| operate(value, head, use_degrees),
+            engine_state.ctrlc.clone(),
+        )
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Get the arccosine of 1",
+                example: "1 | math arccos",
+                result: Some(Value::test_float(0.0f64)),
+            },
+            Example {
+                description: "Get the arccosine of -1 in degrees",
+                example: "-1 | math arccos -d",
+                result: Some(Value::test_float(180.0)),
+            },
+        ]
+    }
+}
+
+fn operate(value: Value, head: Span, use_degrees: bool) -> Value {
+    match value {
+        numeric @ (Value::Int { .. } | Value::Float { .. }) => {
+            let (val, span) = match numeric {
+                Value::Int { val, span } => (val as f64, span),
+                Value::Float { val, span } => (val, span),
+                _ => unreachable!(),
+            };
+
+            if (-1.0..=1.0).contains(&val) {
+                let val = val.acos();
+                let val = if use_degrees { val.to_degrees() } else { val };
+
+                Value::Float { val, span }
+            } else {
+                Value::Error {
+                    error: ShellError::UnsupportedInput(
+                        "'arccos' undefined for values outside the closed interval [-1, 1].".into(),
+                        span,
+                    ),
+                }
+            }
+        }
+        other => Value::Error {
+            error: ShellError::UnsupportedInput(
+                format!(
+                    "Only numerical values are supported, input type: {:?}",
+                    other.get_type()
+                ),
+                other.span().unwrap_or(head),
+            ),
+        },
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+}

crates/nu-command/src/math/arcsin.rs

@@ -0,0 +1,106 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Span, Type, Value};
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "math arcsin"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("math arcsin")
+            .switch("degrees", "Return degrees instead of radians", Some('d'))
+            .input_output_types(vec![(Type::Number, Type::Float)])
+            .vectorizes_over_list(true)
+            .category(Category::Math)
+    }
+
+    fn usage(&self) -> &str {
+        "Returns the arcsine of the number."
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["trigonometry", "inverse"]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        let head = call.head;
+        let use_degrees = call.has_flag("degrees");
+        input.map(
+            move |value| operate(value, head, use_degrees),
+            engine_state.ctrlc.clone(),
+        )
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        let pi = std::f64::consts::PI;
+        vec![
+            Example {
+                description: "Get the arcsine of 1",
+                example: "1 | math arcsin",
+                result: Some(Value::test_float(pi / 2.0)),
+            },
+            Example {
+                description: "Get the arcsine of 1 in degrees",
+                example: "1 | math arcsin -d",
+                result: Some(Value::test_float(90.0)),
+            },
+        ]
+    }
+}
+
+fn operate(value: Value, head: Span, use_degrees: bool) -> Value {
+    match value {
+        numeric @ (Value::Int { .. } | Value::Float { .. }) => {
+            let (val, span) = match numeric {
+                Value::Int { val, span } => (val as f64, span),
+                Value::Float { val, span } => (val, span),
+                _ => unreachable!(),
+            };
+
+            if (-1.0..=1.0).contains(&val) {
+                let val = val.asin();
+                let val = if use_degrees { val.to_degrees() } else { val };
+
+                Value::Float { val, span }
+            } else {
+                Value::Error {
+                    error: ShellError::UnsupportedInput(
+                        "'arcsin' undefined for values outside the closed interval [-1, 1].".into(),
+                        span,
+                    ),
+                }
+            }
+        }
+        other => Value::Error {
+            error: ShellError::UnsupportedInput(
+                format!(
+                    "Only numerical values are supported, input type: {:?}",
+                    other.get_type()
+                ),
+                other.span().unwrap_or(head),
+            ),
+        },
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+}

crates/nu-command/src/math/arctan.rs

@@ -0,0 +1,97 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Span, Type, Value};
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "math arctan"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("math arctan")
+            .switch("degrees", "Return degrees instead of radians", Some('d'))
+            .input_output_types(vec![(Type::Number, Type::Float)])
+            .vectorizes_over_list(true)
+            .category(Category::Math)
+    }
+
+    fn usage(&self) -> &str {
+        "Returns the arctangent of the number."
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["trigonometry", "inverse"]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        let head = call.head;
+        let use_degrees = call.has_flag("degrees");
+        input.map(
+            move |value| operate(value, head, use_degrees),
+            engine_state.ctrlc.clone(),
+        )
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        let pi = std::f64::consts::PI;
+        vec![
+            Example {
+                description: "Get the arctangent of 1",
+                example: "1 | math arctan",
+                result: Some(Value::test_float(pi / 4.0f64)),
+            },
+            Example {
+                description: "Get the arctangent of -1 in degrees",
+                example: "-1 | math arctan -d",
+                result: Some(Value::test_float(-45.0)),
+            },
+        ]
+    }
+}
+
+fn operate(value: Value, head: Span, use_degrees: bool) -> Value {
+    match value {
+        numeric @ (Value::Int { .. } | Value::Float { .. }) => {
+            let (val, span) = match numeric {
+                Value::Int { val, span } => (val as f64, span),
+                Value::Float { val, span } => (val, span),
+                _ => unreachable!(),
+            };
+
+            let val = val.atan();
+            let val = if use_degrees { val.to_degrees() } else { val };
+
+            Value::Float { val, span }
+        }
+        other => Value::Error {
+            error: ShellError::UnsupportedInput(
+                format!(
+                    "Only numerical values are supported, input type: {:?}",
+                    other.get_type()
+                ),
+                other.span().unwrap_or(head),
+            ),
+        },
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+}

crates/nu-command/src/math/mod.rs

@@ -1,4 +1,7 @@
 mod abs;
+mod arccos;
+mod arcsin;
+mod arctan;
 mod avg;
 mod ceil;
 mod cos;
@@ -49,5 +52,9 @@ pub use sinh::SubCommand as MathSinH;
 pub use tan::SubCommand as MathTan;
 pub use tanh::SubCommand as MathTanH;
 
+pub use arccos::SubCommand as MathArcCos;
+pub use arccosh::SubCommand as MathArcCosH;
+pub use arcsin::SubCommand as MathArcSin;
+
 pub use euler::SubCommand as MathEuler;
 pub use pi::SubCommand as MathPi;