Add dice subcommand to random command (#2082)

* Add dice subcommand to random command

* Update random dice test name

* Stream results of random dice

* Thanks Clippy!

crates/nu-cli/src/cli.rs

@@ -394,6 +394,7 @@ pub fn create_default_context(
             // Random value generation
             whole_stream_command(Random),
             whole_stream_command(RandomBool),
+            whole_stream_command(RandomDice),
             whole_stream_command(RandomUUID),
         ]);
 

crates/nu-cli/src/commands.rs

@@ -219,7 +219,7 @@ pub(crate) use pivot::Pivot;
 pub(crate) use prepend::Prepend;
 pub(crate) use prev::Previous;
 pub(crate) use pwd::Pwd;
-pub(crate) use random::{Random, RandomBool, RandomUUID};
+pub(crate) use random::{Random, RandomBool, RandomDice, RandomUUID};
 pub(crate) use range::Range;
 #[allow(unused_imports)]
 pub(crate) use reduce_by::ReduceBy;

crates/nu-cli/src/commands/random/dice.rs

@@ -0,0 +1,103 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+use rand::prelude::{thread_rng, Rng};
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct DiceArgs {
+    dice: Option<Tagged<u32>>,
+    sides: Option<Tagged<u32>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "random dice"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("random dice")
+            .named(
+                "dice",
+                SyntaxShape::Int,
+                "The amount of dice being rolled",
+                Some('d'),
+            )
+            .named(
+                "sides",
+                SyntaxShape::Int,
+                "The amount of sides a die has",
+                Some('s'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Generate a random dice roll"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        dice(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Roll 1 dice with 6 sides each",
+                example: "random dice",
+                result: None,
+            },
+            Example {
+                description: "Roll 10 dice with 12 sides each",
+                example: "random dice -d 10 -s 12",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn dice(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let tag = args.call_info.name_tag.clone();
+    let (DiceArgs { dice, sides }, _) = args.process(&registry).await?;
+
+    let dice = if let Some(dice_tagged) = dice {
+        *dice_tagged
+    } else {
+        1
+    };
+
+    let sides = if let Some(sides_tagged) = sides {
+        *sides_tagged
+    } else {
+        6
+    };
+
+    let iter = (0..dice).map(move |_| {
+        let mut thread_rng = thread_rng();
+        UntaggedValue::int(thread_rng.gen_range(1, sides + 1)).into_value(tag.clone())
+    });
+
+    Ok(futures::stream::iter(iter).to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SubCommand;
+
+    #[test]
+    fn examples_work_as_expected() {
+        use crate::examples::test as test_examples;
+
+        test_examples(SubCommand {})
+    }
+}

crates/nu-cli/src/commands/random/mod.rs

@@ -1,7 +1,11 @@
-pub mod bool;
 pub mod command;
+
+pub mod bool;
+pub mod dice;
 pub mod uuid;
 
-pub use self::bool::SubCommand as RandomBool;
 pub use command::Command as Random;
+
+pub use self::bool::SubCommand as RandomBool;
+pub use dice::SubCommand as RandomDice;
 pub use uuid::SubCommand as RandomUUID;

crates/nu-cli/tests/commands/random/dice.rs

@@ -0,0 +1,13 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn rolls_4_roll() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        random dice -d 4 -s 10 | count
+        "#
+    ));
+
+    assert_eq!(actual.out, "4");
+}

crates/nu-cli/tests/commands/random/mod.rs

@@ -1,2 +1,3 @@
 mod bool;
+mod dice;
 mod uuid;

docs/commands/random.md

@@ -2,17 +2,6 @@
 
 Use `random` to generate random values
 
-## uuid
-
-* `random uuid`: Generate a random uuid4 string
-
-### uuid Examples
-
-```shell
-> random uuid
-8af4de39-acbc-42f0-94d1-7cfad6c01f8b
-```
-
 ## bool
 
 * `random bool`: Generate a random boolean value
@@ -32,3 +21,46 @@ false
 > random bool --bias 0.75
 true
 ```
+
+## dice
+
+* `random dice`: Generate a random dice roll
+
+### dice Flags
+
+* `d`, `--dice` \<integer>: The amount of dice being rolled
+* `s`, `--sides` \<integer>: The amount of sides a die has
+
+### dice Examples
+
+```shell
+> random dice
+4
+```
+
+```shell
+> random dice -d 10 -s 12
+───┬────
+ 0 │ 11
+ 1 │ 11
+ 2 │ 11
+ 3 │ 11
+ 4 │  5
+ 5 │  3
+ 6 │ 10
+ 7 │  7
+ 8 │  3
+ 9 │  1
+───┴────
+```
+
+## uuid
+
+* `random uuid`: Generate a random uuid4 string
+
+### uuid Examples
+
+```shell
+> random uuid
+8af4de39-acbc-42f0-94d1-7cfad6c01f8b
+```