Merge branch 'master' into surf

src/commands/last.rs

@@ -0,0 +1,59 @@
+use crate::commands::WholeStreamCommand;
+use crate::errors::ShellError;
+use crate::parser::CommandRegistry;
+use crate::prelude::*;
+
+pub struct Last;
+
+impl WholeStreamCommand for Last {
+    fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        last(args, registry)
+    }
+
+    fn name(&self) -> &str {
+        "last"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("last").required("amount", SyntaxType::Literal)
+    }
+}
+
+fn last(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let args = args.evaluate_once(registry)?;
+
+    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(),
+            ))
+        }
+    };
+
+    if amount <= 0 {
+        return Err(ShellError::labeled_error(
+            "Value is too low",
+            "expected a positive integer",
+            args.expect_nth(0)?.span(),
+        ))
+    }
+
+    let stream = async_stream_block! {
+        let v: Vec<_> = args.input.into_vec().await;
+        let k = v.len() - (amount as usize);
+        for x in v[k..].iter() {
+            let y: Tagged<Value> = x.clone();
+            yield ReturnSuccess::value(y)
+        }
+    };
+    Ok(stream.to_output_stream())
+}

src/commands/sort_by.rs

@@ -18,7 +18,7 @@ impl WholeStreamCommand for SortBy {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("sort-by")
+        Signature::build("sort-by").switch("reverse")
     }
 }
 
@@ -37,13 +37,21 @@ fn sort_by(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream
 
     let output = input.values.collect::<Vec<_>>();
 
+    let reverse = args.has("reverse");
     let output = output.map(move |mut vec| {
-        vec.sort_by_key(|item| {
+        let calc_key = |item: &Tagged<Value>| {
             fields
                 .iter()
                 .map(|f| item.get_data_by_key(f).map(|i| i.clone()))
                 .collect::<Vec<Option<Tagged<Value>>>>()
-        });
+        };
+        if reverse {
+            vec.sort_by_cached_key(|item| {
+                std::cmp::Reverse(calc_key(item))
+            });
+        } else {
+            vec.sort_by_cached_key(calc_key);
+        }
 
         vec.into_iter().collect::<VecDeque<_>>()
     });