Engine-p style in compact (#3325)

* Engine-p style in compact

* Remove unused import

* Use filter in compact, thanks to clippy for spotting it :]

crates/nu-command/src/commands/compact.rs

@@ -2,14 +2,13 @@ use crate::prelude::*;
 
 use nu_engine::WholeStreamCommand;
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
 use nu_source::Tagged;
 
 pub struct Compact;
 
-#[derive(Deserialize)]
 pub struct CompactArgs {
-    rest: Vec<Tagged<String>>,
+    columns: Vec<Tagged<String>>,
 }
 
 impl WholeStreamCommand for Compact {
@@ -25,7 +24,7 @@ impl WholeStreamCommand for Compact {
         "Creates a table with non-empty rows."
     }
 
-    fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
+    fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         compact(args)
     }
 
@@ -38,36 +37,30 @@ impl WholeStreamCommand for Compact {
     }
 }
 
-pub fn compact(args: CommandArgs) -> Result<ActionStream, ShellError> {
+pub fn compact(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let (CompactArgs { rest: columns }, input) = args.process()?;
+    let (args, input) = args.extract(|params| {
+        Ok(CompactArgs {
+            columns: params.rest(0)?,
+        })
+    })?;
+
     Ok(input
-        .filter_map(move |item| {
+        .filter(move |item| {
-            if columns.is_empty() {
+            if args.columns.is_empty() {
-                if !item.is_empty() {
+                !item.is_empty()
-                    Some(ReturnSuccess::value(item))
+            } else if let Value {
-                } else {
+                value: UntaggedValue::Row(ref r),
-                    None
+                ..
-                }
+            } = item
+            {
+                args.columns
+                    .iter()
+                    .all(|field| r.get_data(field).borrow().is_some())
             } else {
-                match item {
+                false
-                    Value {
-                        value: UntaggedValue::Row(ref r),
-                        ..
-                    } => {
-                        if columns
-                            .iter()
-                            .all(|field| r.get_data(field).borrow().is_some())
-                        {
-                            Some(ReturnSuccess::value(item))
-                        } else {
-                            None
-                        }
-                    }
-                    _ => None,
-                }
             }
         })
-        .to_action_stream())
+        .to_output_stream())
 }
 
 #[cfg(test)]