--- a/rust/rhg/src/commands/cat.rs	Mon Feb 08 11:13:56 2021 +0100
+++ b/rust/rhg/src/commands/cat.rs	Mon Feb 08 20:33:04 2021 +0100
@@ -1,6 +1,6 @@
-use crate::commands::Command;
 use crate::error::CommandError;
 use crate::ui::Ui;
+use clap::ArgMatches;
 use hg::config::Config;
 use hg::operations::cat;
 use hg::repo::Repo;
@@ -12,47 +12,40 @@
 Output the current or given revision of files
 ";
 
-pub struct CatCommand<'a> {
-    rev: Option<&'a str>,
-    files: Vec<&'a str>,
-}
+#[timed]
+pub fn run(
+    ui: &Ui,
+    config: &Config,
+    args: &ArgMatches,
+) -> Result<(), CommandError> {
+    let rev = args.value_of("rev");
+    let file_args = match args.values_of("files") {
+        Some(files) => files.collect(),
+        None => vec![],
+    };
 
-impl<'a> CatCommand<'a> {
-    pub fn new(rev: Option<&'a str>, files: Vec<&'a str>) -> Self {
-        Self { rev, files }
+    let repo = Repo::find(config)?;
+    let cwd = hg::utils::current_dir()?;
+
+    let mut files = vec![];
+    for file in file_args.iter() {
+        // TODO: actually normalize `..` path segments etc?
+        let normalized = cwd.join(&file);
+        let stripped = normalized
+            .strip_prefix(&repo.working_directory_path())
+            // TODO: error message for path arguments outside of the repo
+            .map_err(|_| CommandError::abort(""))?;
+        let hg_file = HgPathBuf::try_from(stripped.to_path_buf())
+            .map_err(|e| CommandError::abort(e.to_string()))?;
+        files.push(hg_file);
     }
 
-    fn display(&self, ui: &Ui, data: &[u8]) -> Result<(), CommandError> {
-        ui.write_stdout(data)?;
-        Ok(())
+    match rev {
+        Some(rev) => {
+            let data = cat(&repo, rev, &files).map_err(|e| (e, rev))?;
+            ui.write_stdout(&data)?;
+            Ok(())
+        }
+        None => Err(CommandError::Unimplemented.into()),
     }
 }
-
-impl<'a> Command for CatCommand<'a> {
-    #[timed]
-    fn run(&self, ui: &Ui, config: &Config) -> Result<(), CommandError> {
-        let repo = Repo::find(config)?;
-        let cwd = hg::utils::current_dir()?;
-
-        let mut files = vec![];
-        for file in self.files.iter() {
-            // TODO: actually normalize `..` path segments etc?
-            let normalized = cwd.join(&file);
-            let stripped = normalized
-                .strip_prefix(&repo.working_directory_path())
-                // TODO: error message for path arguments outside of the repo
-                .map_err(|_| CommandError::abort(""))?;
-            let hg_file = HgPathBuf::try_from(stripped.to_path_buf())
-                .map_err(|e| CommandError::abort(e.to_string()))?;
-            files.push(hg_file);
-        }
-
-        match self.rev {
-            Some(rev) => {
-                let data = cat(&repo, rev, &files).map_err(|e| (e, rev))?;
-                self.display(ui, &data)
-            }
-            None => Err(CommandError::Unimplemented.into()),
-        }
-    }
-}