New math commands(product, round, sqrt and sum)

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

@@ -0,0 +1,58 @@
+use crate::math::reducers::{reducer_for, Reduce};
+use crate::math::utils::run_with_function;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Example, PipelineData, ShellError, Signature, Span, Value};
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "math product"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("math product")
+    }
+
+    fn usage(&self) -> &str {
+        "Finds the product of a list of numbers or tables"
+    }
+
+    fn run(
+        &self,
+        _engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        run_with_function(call, input, product)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Get the product of a list of numbers",
+            example: "[2 3 3 4] | math product",
+            result: Some(Value::test_int(72)),
+        }]
+    }
+}
+
+/// Calculate product of given values
+pub fn product(values: &[Value], head: &Span) -> Result<Value, ShellError> {
+    let product_func = reducer_for(Reduce::Product);
+    product_func(Value::nothing(), values.to_vec(), *head)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+}