From 1098a348aa4538158464404d3c9cf9aab3ea39b3 Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Tue, 13 Feb 2024 18:08:24 -0500
Subject: [PATCH] Parse and execute macro mappable commands

---
 helix-term/src/commands.rs | 49 +++++++++++++++++++++++++++++++++++---
 helix-term/src/keymap.rs   |  1 +
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 835283ada..9ccd8ea10 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -176,9 +176,16 @@ where
 
 use helix_view::{align_view, Align};
 
-/// A MappableCommand is either a static command like "jump_view_up" or a Typable command like
-/// :format. It causes a side-effect on the state (usually by creating and applying a transaction).
-/// Both of these types of commands can be mapped with keybindings in the config.toml.
+/// MappableCommands are commands that can be bound to keys, executable in
+/// normal, insert or select mode.
+///
+/// There are three kinds:
+///
+/// * Static: commands usually bound to keys and used for editing, movement,
+///   etc., for example `move_char_left`.
+/// * Typable: commands executable from command mode, prefixed with a `:`,
+///   for example `:write!`.
+/// * Macro: a sequence of keys to execute, for example `@miw`.
 #[derive(Clone)]
 pub enum MappableCommand {
     Typable {
@@ -191,6 +198,10 @@ pub enum MappableCommand {
         fun: fn(cx: &mut Context),
         doc: &'static str,
     },
+    Macro {
+        name: String,
+        keys: Vec<KeyEvent>,
+    },
 }
 
 macro_rules! static_commands {
@@ -227,6 +238,23 @@ impl MappableCommand {
                 }
             }
             Self::Static { fun, .. } => (fun)(cx),
+            Self::Macro { keys, .. } => {
+                // Protect against recursive macros.
+                if cx.editor.macro_replaying.contains(&'@') {
+                    cx.editor.set_error(
+                        "Cannot execute macro because the [@] register is already playing a macro",
+                    );
+                    return;
+                }
+                cx.editor.macro_replaying.push('@');
+                let keys = keys.clone();
+                cx.callback.push(Box::new(move |compositor, cx| {
+                    for key in keys.into_iter() {
+                        compositor.handle_event(&compositor::Event::Key(key), cx);
+                    }
+                    cx.editor.macro_replaying.pop();
+                }));
+            }
         }
     }
 
@@ -234,6 +262,7 @@ impl MappableCommand {
         match &self {
             Self::Typable { name, .. } => name,
             Self::Static { name, .. } => name,
+            Self::Macro { name, .. } => name,
         }
     }
 
@@ -241,6 +270,7 @@ impl MappableCommand {
         match &self {
             Self::Typable { doc, .. } => doc,
             Self::Static { doc, .. } => doc,
+            Self::Macro { name, .. } => name,
         }
     }
 
@@ -551,6 +581,11 @@ impl fmt::Debug for MappableCommand {
                 .field(name)
                 .field(args)
                 .finish(),
+            MappableCommand::Macro { name, keys, .. } => f
+                .debug_tuple("MappableCommand")
+                .field(name)
+                .field(keys)
+                .finish(),
         }
     }
 }
@@ -581,6 +616,11 @@ impl std::str::FromStr for MappableCommand {
                     args,
                 })
                 .ok_or_else(|| anyhow!("No TypableCommand named '{}'", s))
+        } else if let Some(suffix) = s.strip_prefix('@') {
+            helix_view::input::parse_macro(suffix).map(|keys| Self::Macro {
+                name: s.to_string(),
+                keys,
+            })
         } else {
             MappableCommand::STATIC_COMMAND_LIST
                 .iter()
@@ -3185,6 +3225,9 @@ pub fn command_palette(cx: &mut Context) {
                 ui::PickerColumn::new("name", |item, _| match item {
                     MappableCommand::Typable { name, .. } => format!(":{name}").into(),
                     MappableCommand::Static { name, .. } => (*name).into(),
+                    MappableCommand::Macro { .. } => {
+                        unreachable!("macros aren't included in the command palette")
+                    }
                 }),
                 ui::PickerColumn::new(
                     "bindings",
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index 975274ed1..4d8d13d64 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -199,6 +199,7 @@ impl KeyTrie {
         // recursively visit all nodes in keymap
         fn map_node(cmd_map: &mut ReverseKeymap, node: &KeyTrie, keys: &mut Vec<KeyEvent>) {
             match node {
+                KeyTrie::MappableCommand(MappableCommand::Macro { .. }) => {}
                 KeyTrie::MappableCommand(cmd) => {
                     let name = cmd.name();
                     if name != "no_op" {