From 14e47f3d2c34d4383290e7453a19e9f571cb2650 Mon Sep 17 00:00:00 2001
From: Jonathan Turner <jonathan.d.turner@gmail.com>
Date: Mon, 12 Aug 2019 17:13:58 +1200
Subject: [PATCH] Add nth command

---
 src/cli.rs            |  1 +
 src/commands.rs       |  1 +
 src/commands/first.rs |  2 --
 src/commands/nth.rs   | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 src/commands/nth.rs

diff --git a/src/cli.rs b/src/cli.rs
index af8105872..d5b87efa0 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -158,6 +158,7 @@ pub async fn cli() -> Result<(), Box<dyn Error>> {
             command("size", Box::new(size::size)),
             command("from-yaml", Box::new(from_yaml::from_yaml)),
             command("enter", Box::new(enter::enter)),
+            command("nth", Box::new(nth::nth)),
             command("n", Box::new(next::next)),
             command("p", Box::new(prev::prev)),
             command("lines", Box::new(lines::lines)),
diff --git a/src/commands.rs b/src/commands.rs
index 9366257a8..b3f7b3b00 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -24,6 +24,7 @@ crate mod lines;
 crate mod ls;
 crate mod mkdir;
 crate mod next;
+crate mod nth;
 crate mod open;
 crate mod pick;
 crate mod plugin;
diff --git a/src/commands/first.rs b/src/commands/first.rs
index f34b9dba0..a48e55593 100644
--- a/src/commands/first.rs
+++ b/src/commands/first.rs
@@ -2,8 +2,6 @@ use crate::errors::ShellError;
 use crate::parser::CommandRegistry;
 use crate::prelude::*;
 
-// TODO: "Amount remaining" wrapper
-
 pub fn first(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
     let args = args.evaluate_once(registry)?;
 
diff --git a/src/commands/nth.rs b/src/commands/nth.rs
new file mode 100644
index 000000000..96e29f009
--- /dev/null
+++ b/src/commands/nth.rs
@@ -0,0 +1,32 @@
+use crate::errors::ShellError;
+use crate::parser::CommandRegistry;
+use crate::prelude::*;
+
+pub fn nth(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let args = args.evaluate_once(registry)?;
+
+    if args.len() == 0 {
+        return Err(ShellError::labeled_error(
+            "Nth requires an amount",
+            "needs amount",
+            args.name_span(),
+        ));
+    }
+
+    let amount = args.expect_nth(0)?.as_i64();
+
+    let amount = match amount {
+        Ok(o) => o,
+        Err(_) => {
+            return Err(ShellError::labeled_error(
+                "Value is not a number",
+                "expected integer",
+                args.expect_nth(0)?.span(),
+            ))
+        }
+    };
+
+    Ok(OutputStream::from_input(
+        args.input.values.skip(amount as u64).take(1),
+    ))
+}