Refactor key into helix-view

Now also make use of Deserialize for Config.

9 files changed, 388 insertions, 414 deletions

diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 2fae467f..ce43808a 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -1,7 +1,7 @@
 use helix_lsp::{lsp, LspProgressMap};
 use helix_view::{document::Mode, Document, Editor, Theme, View};
 
-use crate::{args::Args, compositor::Compositor, config::Config, keymap::Keymaps, ui};
+use crate::{args::Args, compositor::Compositor, config::Config, ui};
 
 use log::{error, info};
 
@@ -49,7 +49,7 @@ impl Application {
         let size = compositor.size();
         let mut editor = Editor::new(size);
 
-        let mut editor_view = Box::new(ui::EditorView::new(config.keymaps));
+        let mut editor_view = Box::new(ui::EditorView::new(config.keys));
         compositor.push(editor_view);
 
         if !args.files.is_empty() {
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index a8610223..1243a86f 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -11,6 +11,7 @@ use helix_core::{
 
 use helix_view::{
     document::{IndentStyle, Mode},
+    input::{KeyCode, KeyEvent},
     view::{View, PADDING},
     Document, DocumentId, Editor, ViewId,
 };
@@ -38,8 +39,8 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use crossterm::event::{KeyCode, KeyEvent};
 use once_cell::sync::Lazy;
+use serde::de::{self, Deserialize, Deserializer};
 
 pub struct Context<'a> {
     pub selected_register: helix_view::RegisterSelection,
@@ -252,6 +253,48 @@ impl Command {
     );
 }
 
+impl fmt::Debug for Command {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let Command(name, _) = self;
+        f.debug_tuple("Command").field(name).finish()
+    }
+}
+
+impl fmt::Display for Command {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let Command(name, _) = self;
+        f.write_str(name)
+    }
+}
+
+impl std::str::FromStr for Command {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Command::COMMAND_LIST
+            .iter()
+            .copied()
+            .find(|cmd| cmd.0 == s)
+            .ok_or_else(|| anyhow!("No command named '{}'", s))
+    }
+}
+
+impl<'de> Deserialize<'de> for Command {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        s.parse().map_err(de::Error::custom)
+    }
+}
+
+impl PartialEq for Command {
+    fn eq(&self, other: &Self) -> bool {
+        self.name() == other.name()
+    }
+}
+
 fn move_char_left(cx: &mut Context) {
     let count = cx.count();
     let (view, doc) = current!(cx.editor);
@@ -3042,29 +3085,3 @@ fn right_bracket_mode(cx: &mut Context) {
         }
     })
 }
-
-impl fmt::Display for Command {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let Command(name, _) = self;
-        f.write_str(name)
-    }
-}
-
-impl std::str::FromStr for Command {
-    type Err = anyhow::Error;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Command::COMMAND_LIST
-            .iter()
-            .copied()
-            .find(|cmd| cmd.0 == s)
-            .ok_or_else(|| anyhow!("No command named '{}'", s))
-    }
-}
-
-impl fmt::Debug for Command {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let Command(name, _) = self;
-        f.debug_tuple("Command").field(name).finish()
-    }
-}
diff --git a/helix-term/src/config.rs b/helix-term/src/config.rs
index e5e17753..9c962299 100644
--- a/helix-term/src/config.rs
+++ b/helix-term/src/config.rs
@@ -1,10 +1,9 @@
-use anyhow::{Error, Result};
-use std::{collections::HashMap, str::FromStr};
+use serde::Deserialize;
 
-use serde::{de::Error as SerdeError, Deserialize, Serialize};
-
-use crate::keymap::{parse_keymaps, Keymaps};
+use crate::commands::Command;
+use crate::keymap::Keymaps;
 
+#[derive(Debug, PartialEq, Deserialize)]
 pub struct GlobalConfig {
     pub lsp_progress: bool,
 }
@@ -15,35 +14,50 @@ impl Default for GlobalConfig {
     }
 }
 
-#[derive(Default)]
+#[derive(Debug, Default, PartialEq, Deserialize)]
+#[serde(default)]
 pub struct Config {
     pub global: GlobalConfig,
-    pub keymaps: Keymaps,
+    pub keys: Keymaps,
 }
 
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "kebab-case")]
-struct TomlConfig {
-    lsp_progress: Option<bool>,
-    keys: Option<HashMap<String, HashMap<String, String>>>,
-}
+#[test]
+fn parsing_keymaps_config_file() {
+    use helix_core::hashmap;
+    use helix_view::document::Mode;
+    use helix_view::input::{KeyCode, KeyEvent, KeyModifiers};
 
-impl<'de> Deserialize<'de> for Config {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let config = TomlConfig::deserialize(deserializer)?;
-        Ok(Self {
-            global: GlobalConfig {
-                lsp_progress: config.lsp_progress.unwrap_or(true),
-            },
-            keymaps: config
-                .keys
-                .map(|r| parse_keymaps(&r))
-                .transpose()
-                .map_err(|e| D::Error::custom(format!("Error deserializing keymap: {}", e)))?
-                .unwrap_or_else(Keymaps::default),
-        })
-    }
+    let sample_keymaps = r#"
+            [keys.insert]
+            y = "move_line_down"
+            S-C-a = "delete_selection"
+
+            [keys.normal]
+            A-F12 = "move_next_word_end"
+        "#;
+
+    assert_eq!(
+        toml::from_str::<Config>(sample_keymaps).unwrap(),
+        Config {
+            global: Default::default(),
+            keys: Keymaps(hashmap! {
+                Mode::Insert => hashmap! {
+                    KeyEvent {
+                        code: KeyCode::Char('y'),
+                        modifiers: KeyModifiers::NONE,
+                    } => Command::move_line_down,
+                    KeyEvent {
+                        code: KeyCode::Char('a'),
+                        modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL,
+                    } => Command::delete_selection,
+                },
+                Mode::Normal => hashmap! {
+                    KeyEvent {
+                        code: KeyCode::F(12),
+                        modifiers: KeyModifiers::ALT,
+                    } => Command::move_next_word_end,
+                },
+            })
+        }
+    );
 }
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index f6bcbcc9..24924832 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -3,6 +3,8 @@ pub use crate::commands::Command;
 use anyhow::{anyhow, Error, Result};
 use helix_core::hashmap;
 use helix_view::document::Mode;
+use helix_view::input::{KeyCode, KeyEvent, KeyModifiers};
+use serde::Deserialize;
 use std::{
     collections::HashMap,
     fmt::Display,
@@ -99,14 +101,6 @@ use std::{
 //      D] = last diagnostic
 // }
 
-// #[cfg(feature = "term")]
-pub use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
-
-#[derive(Clone, Debug)]
-pub struct Keymap(pub HashMap<KeyEvent, Command>);
-#[derive(Clone, Debug)]
-pub struct Keymaps(pub HashMap<Mode, Keymap>);
-
 #[macro_export]
 macro_rules! key {
     ($key:ident) => {
@@ -141,9 +135,21 @@ macro_rules! alt {
     };
 }
 
+#[derive(Debug, PartialEq, Deserialize)]
+#[serde(transparent)]
+pub struct Keymaps(pub HashMap<Mode, HashMap<KeyEvent, Command>>);
+
+impl Deref for Keymaps {
+    type Target = HashMap<Mode, HashMap<KeyEvent, Command>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 impl Default for Keymaps {
-    fn default() -> Self {
-        let normal = Keymap(hashmap!(
+    fn default() -> Keymaps {
+        let normal = hashmap!(
             key!('h') => Command::move_char_left,
             key!('j') => Command::move_line_down,
             key!('k') => Command::move_line_up,
@@ -277,12 +283,12 @@ impl Default for Keymaps {
             key!('z') => Command::view_mode,
 
             key!('"') => Command::select_register,
-        ));
+        );
         // TODO: decide whether we want normal mode to also be select mode (kakoune-like), or whether
         // we keep this separate select mode. More keys can fit into normal mode then, but it's weird
         // because some selection operations can now be done from normal mode, some from select mode.
         let mut select = normal.clone();
-        select.0.extend(
+        select.extend(
             hashmap!(
                 key!('h') => Command::extend_char_left,
                 key!('j') => Command::extend_line_down,
@@ -315,7 +321,7 @@ impl Default for Keymaps {
             // TODO: select could be normal mode with some bindings merged over
             Mode::Normal => normal,
             Mode::Select => select,
-            Mode::Insert => Keymap(hashmap!(
+            Mode::Insert => hashmap!(
                 key!(Esc) => Command::normal_mode as Command,
                 key!(Backspace) => Command::delete_char_backward,
                 key!(Delete) => Command::delete_char_forward,
@@ -329,309 +335,7 @@ impl Default for Keymaps {
                 key!(PageDown) => Command::page_down,
                 ctrl!('x') => Command::completion,
                 ctrl!('w') => Command::delete_word_backward,
-            )),
+            ),
         ))
     }
 }
-
-// Newtype wrapper over keys to allow toml serialization/parsing
-#[derive(Debug, PartialEq, PartialOrd, Clone, Copy, Hash)]
-pub struct RepresentableKeyEvent(pub KeyEvent);
-impl Display for RepresentableKeyEvent {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let Self(key) = self;
-        f.write_fmt(format_args!(
-            "{}{}{}",
-            if key.modifiers.contains(KeyModifiers::SHIFT) {
-                "S-"
-            } else {
-                ""
-            },
-            if key.modifiers.contains(KeyModifiers::ALT) {
-                "A-"
-            } else {
-                ""
-            },
-            if key.modifiers.contains(KeyModifiers::CONTROL) {
-                "C-"
-            } else {
-                ""
-            },
-        ))?;
-        match key.code {
-            KeyCode::Backspace => f.write_str("backspace")?,
-            KeyCode::Enter => f.write_str("ret")?,
-            KeyCode::Left => f.write_str("left")?,
-            KeyCode::Right => f.write_str("right")?,
-            KeyCode::Up => f.write_str("up")?,
-            KeyCode::Down => f.write_str("down")?,
-            KeyCode::Home => f.write_str("home")?,
-            KeyCode::End => f.write_str("end")?,
-            KeyCode::PageUp => f.write_str("pageup")?,
-            KeyCode::PageDown => f.write_str("pagedown")?,
-            KeyCode::Tab => f.write_str("tab")?,
-            KeyCode::BackTab => f.write_str("backtab")?,
-            KeyCode::Delete => f.write_str("del")?,
-            KeyCode::Insert => f.write_str("ins")?,
-            KeyCode::Null => f.write_str("null")?,
-            KeyCode::Esc => f.write_str("esc")?,
-            KeyCode::Char('<') => f.write_str("lt")?,
-            KeyCode::Char('>') => f.write_str("gt")?,
-            KeyCode::Char('+') => f.write_str("plus")?,
-            KeyCode::Char('-') => f.write_str("minus")?,
-            KeyCode::Char(';') => f.write_str("semicolon")?,
-            KeyCode::Char('%') => f.write_str("percent")?,
-            KeyCode::F(i) => f.write_fmt(format_args!("F{}", i))?,
-            KeyCode::Char(c) => f.write_fmt(format_args!("{}", c))?,
-        };
-        Ok(())
-    }
-}
-
-impl FromStr for RepresentableKeyEvent {
-    type Err = Error;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let mut tokens: Vec<_> = s.split('-').collect();
-        let code = match tokens.pop().ok_or_else(|| anyhow!("Missing key code"))? {
-            "backspace" => KeyCode::Backspace,
-            "space" => KeyCode::Char(' '),
-            "ret" => KeyCode::Enter,
-            "lt" => KeyCode::Char('<'),
-            "gt" => KeyCode::Char('>'),
-            "plus" => KeyCode::Char('+'),
-            "minus" => KeyCode::Char('-'),
-            "semicolon" => KeyCode::Char(';'),
-            "percent" => KeyCode::Char('%'),
-            "left" => KeyCode::Left,
-            "right" => KeyCode::Right,
-            "up" => KeyCode::Down,
-            "home" => KeyCode::Home,
-            "end" => KeyCode::End,
-            "pageup" => KeyCode::PageUp,
-            "pagedown" => KeyCode::PageDown,
-            "tab" => KeyCode::Tab,
-            "backtab" => KeyCode::BackTab,
-            "del" => KeyCode::Delete,
-            "ins" => KeyCode::Insert,
-            "null" => KeyCode::Null,
-            "esc" => KeyCode::Esc,
-            single if single.len() == 1 => KeyCode::Char(single.chars().next().unwrap()),
-            function if function.len() > 1 && function.starts_with('F') => {
-                let function: String = function.chars().skip(1).collect();
-                let function = str::parse::<u8>(&function)?;
-                (function > 0 && function < 13)
-                    .then(|| KeyCode::F(function))
-                    .ok_or_else(|| anyhow!("Invalid function key '{}'", function))?
-            }
-            invalid => return Err(anyhow!("Invalid key code '{}'", invalid)),
-        };
-
-        let mut modifiers = KeyModifiers::empty();
-        for token in tokens {
-            let flag = match token {
-                "S" => KeyModifiers::SHIFT,
-                "A" => KeyModifiers::ALT,
-                "C" => KeyModifiers::CONTROL,
-                _ => return Err(anyhow!("Invalid key modifier '{}-'", token)),
-            };
-
-            if modifiers.contains(flag) {
-                return Err(anyhow!("Repeated key modifier '{}-'", token));
-            }
-            modifiers.insert(flag);
-        }
-
-        Ok(RepresentableKeyEvent(KeyEvent { code, modifiers }))
-    }
-}
-
-pub fn parse_keymaps(toml_keymaps: &HashMap<String, HashMap<String, String>>) -> Result<Keymaps> {
-    let mut keymaps = Keymaps::default();
-
-    for (mode, map) in toml_keymaps {
-        let mode = Mode::from_str(&mode)?;
-        for (key, command) in map {
-            let key = str::parse::<RepresentableKeyEvent>(&key)?;
-            let command = str::parse::<Command>(&command)?;
-            keymaps.0.get_mut(&mode).unwrap().0.insert(key.0, command);
-        }
-    }
-    Ok(keymaps)
-}
-
-impl Deref for Keymap {
-    type Target = HashMap<KeyEvent, Command>;
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl Deref for Keymaps {
-    type Target = HashMap<Mode, Keymap>;
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl DerefMut for Keymap {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.0
-    }
-}
-
-impl DerefMut for Keymaps {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.0
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use crate::config::Config;
-
-    use super::*;
-
-    impl PartialEq for Command {
-        fn eq(&self, other: &Self) -> bool {
-            self.name() == other.name()
-        }
-    }
-
-    #[test]
-    fn parsing_keymaps_config_file() {
-        let sample_keymaps = r#"
-            [keys.insert]
-            y = "move_line_down"
-            S-C-a = "delete_selection"
-
-            [keys.normal]
-            A-F12 = "move_next_word_end"
-        "#;
-
-        let config: Config = toml::from_str(sample_keymaps).unwrap();
-        assert_eq!(
-            *config
-                .keymaps
-                .0
-                .get(&Mode::Insert)
-                .unwrap()
-                .0
-                .get(&KeyEvent {
-                    code: KeyCode::Char('y'),
-                    modifiers: KeyModifiers::NONE
-                })
-                .unwrap(),
-            Command::move_line_down
-        );
-        assert_eq!(
-            *config
-                .keymaps
-                .0
-                .get(&Mode::Insert)
-                .unwrap()
-                .0
-                .get(&KeyEvent {
-                    code: KeyCode::Char('a'),
-                    modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL
-                })
-                .unwrap(),
-            Command::delete_selection
-        );
-        assert_eq!(
-            *config
-                .keymaps
-                .0
-                .get(&Mode::Normal)
-                .unwrap()
-                .0
-                .get(&KeyEvent {
-                    code: KeyCode::F(12),
-                    modifiers: KeyModifiers::ALT
-                })
-                .unwrap(),
-            Command::move_next_word_end
-        );
-    }
-
-    #[test]
-    fn parsing_unmodified_keys() {
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("backspace").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::Backspace,
-                modifiers: KeyModifiers::NONE
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("left").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::Left,
-                modifiers: KeyModifiers::NONE
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>(",").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::Char(','),
-                modifiers: KeyModifiers::NONE
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("w").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::Char('w'),
-                modifiers: KeyModifiers::NONE
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("F12").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::F(12),
-                modifiers: KeyModifiers::NONE
-            })
-        );
-    }
-
-    fn parsing_modified_keys() {
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("S-minus").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::Char('-'),
-                modifiers: KeyModifiers::SHIFT
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("C-A-S-F12").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::F(12),
-                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL | KeyModifiers::ALT
-            })
-        );
-
-        assert_eq!(
-            str::parse::<RepresentableKeyEvent>("S-C-2").unwrap(),
-            RepresentableKeyEvent(KeyEvent {
-                code: KeyCode::F(2),
-                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL
-            })
-        );
-    }
-
-    #[test]
-    fn parsing_nonsensical_keys_fails() {
-        assert!(str::parse::<RepresentableKeyEvent>("F13").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("F0").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("aaa").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("S-S-a").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("C-A-S-C-1").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("FU").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("123").is_err());
-        assert!(str::parse::<RepresentableKeyEvent>("S--").is_err());
-    }
-}
diff --git a/helix-term/src/main.rs b/helix-term/src/main.rs
index ef912480..12176910 100644
--- a/helix-term/src/main.rs
+++ b/helix-term/src/main.rs
@@ -1,10 +1,9 @@
+use anyhow::{Context, Error, Result};
 use helix_term::application::Application;
 use helix_term::args::Args;
 use helix_term::config::Config;
 use std::path::PathBuf;
 
-use anyhow::{Context, Result};
-
 fn setup_logging(logpath: PathBuf, verbosity: u64) -> Result<()> {
     let mut base_config = fern::Dispatch::new();
 
@@ -89,12 +88,11 @@ FLAGS:
         std::fs::create_dir_all(&conf_dir).ok();
     }
 
-    let config = std::fs::read_to_string(conf_dir.join("config.toml"))
-        .ok()
-        .map(|s| toml::from_str(&s))
-        .transpose()?
-        .or_else(|| Some(Config::default()))
-        .unwrap();
+    let config = match std::fs::read_to_string(conf_dir.join("config.toml")) {
+        Ok(config) => toml::from_str(&config)?,
+        Err(err) if err.kind() == std::io::ErrorKind::NotFound => Config::default(),
+        Err(err) => return Err(Error::new(err)),
+    };
 
     setup_logging(logpath, args.verbosity).context("failed to initialize logging")?;
 
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 3dc43d3f..d0eedad6 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -11,12 +11,13 @@ use helix_core::{
     syntax::{self, HighlightEvent},
     Position, Range,
 };
+use helix_view::input::{KeyCode, KeyEvent, KeyModifiers};
 use helix_view::{document::Mode, Document, Editor, Theme, View};
 use std::borrow::Cow;
 
 use crossterm::{
     cursor,
-    event::{read, Event, EventStream, KeyCode, KeyEvent, KeyModifiers},
+    event::{read, Event, EventStream},
 };
 use tui::{
     backend::CrosstermBackend,
@@ -607,7 +608,8 @@ impl Component for EditorView {
                 cx.editor.resize(Rect::new(0, 0, width, height - 1));
                 EventResult::Consumed(None)
             }
-            Event::Key(mut key) => {
+            Event::Key(key) => {
+                let mut key = KeyEvent::from(key);
                 canonicalize_key(&mut key);
                 // clear status
                 cx.editor.status_msg = None;
diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index e9a8097c..8875f70d 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -1,5 +1,7 @@
 use anyhow::{anyhow, Context, Error};
+use serde::de::{self, Deserialize, Deserializer};
 use std::cell::Cell;
+use std::collections::HashMap;
 use std::fmt::Display;
 use std::future::Future;
 use std::path::{Component, Path, PathBuf};
@@ -15,8 +17,6 @@ use helix_core::{
 
 use crate::{DocumentId, ViewId};
 
-use std::collections::HashMap;
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum Mode {
     Normal,
@@ -24,6 +24,40 @@ pub enum Mode {
     Insert,
 }
 
+impl Display for Mode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Mode::Normal => f.write_str("normal"),
+            Mode::Select => f.write_str("select"),
+            Mode::Insert => f.write_str("insert"),
+        }
+    }
+}
+
+impl FromStr for Mode {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "normal" => Ok(Mode::Normal),
+            "select" => Ok(Mode::Select),
+            "insert" => Ok(Mode::Insert),
+            _ => Err(anyhow!("Invalid mode '{}'", s)),
+        }
+    }
+}
+
+// toml deserializer doesn't seem to recognize string as enum
+impl<'de> Deserialize<'de> for Mode {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        s.parse().map_err(de::Error::custom)
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum IndentStyle {
     Tabs,
@@ -88,29 +122,6 @@ impl fmt::Debug for Document {
     }
 }
 
-impl Display for Mode {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Mode::Normal => f.write_str("normal"),
-            Mode::Select => f.write_str("select"),
-            Mode::Insert => f.write_str("insert"),
-        }
-    }
-}
-
-impl FromStr for Mode {
-    type Err = Error;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "normal" => Ok(Mode::Normal),
-            "select" => Ok(Mode::Select),
-            "insert" => Ok(Mode::Insert),
-            _ => Err(anyhow!("Invalid mode '{}'", s)),
-        }
-    }
-}
-
 /// Like std::mem::replace() except it allows the replacement value to be mapped from the
 /// original value.
 fn take_with<T, F>(mut_ref: &mut T, closure: F)
diff --git a/helix-view/src/input.rs b/helix-view/src/input.rs
new file mode 100644
index 00000000..ab417819
--- /dev/null
+++ b/helix-view/src/input.rs
@@ -0,0 +1,226 @@
+//! Input event handling, currently backed by crossterm.
+use anyhow::{anyhow, Error};
+use crossterm::event;
+use serde::de::{self, Deserialize, Deserializer};
+use std::fmt;
+
+pub use crossterm::event::{KeyCode, KeyModifiers};
+
+/// Represents a key event.
+// We use a newtype here because we want to customize Deserialize and Display.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Clone, Copy, Hash)]
+pub struct KeyEvent {
+    pub code: KeyCode,
+    pub modifiers: KeyModifiers,
+}
+
+impl fmt::Display for KeyEvent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_fmt(format_args!(
+            "{}{}{}",
+            if self.modifiers.contains(KeyModifiers::SHIFT) {
+                "S-"
+            } else {
+                ""
+            },
+            if self.modifiers.contains(KeyModifiers::ALT) {
+                "A-"
+            } else {
+                ""
+            },
+            if self.modifiers.contains(KeyModifiers::CONTROL) {
+                "C-"
+            } else {
+                ""
+            },
+        ))?;
+        match self.code {
+            KeyCode::Backspace => f.write_str("backspace")?,
+            KeyCode::Enter => f.write_str("ret")?,
+            KeyCode::Left => f.write_str("left")?,
+            KeyCode::Right => f.write_str("right")?,
+            KeyCode::Up => f.write_str("up")?,
+            KeyCode::Down => f.write_str("down")?,
+            KeyCode::Home => f.write_str("home")?,
+            KeyCode::End => f.write_str("end")?,
+            KeyCode::PageUp => f.write_str("pageup")?,
+            KeyCode::PageDown => f.write_str("pagedown")?,
+            KeyCode::Tab => f.write_str("tab")?,
+            KeyCode::BackTab => f.write_str("backtab")?,
+            KeyCode::Delete => f.write_str("del")?,
+            KeyCode::Insert => f.write_str("ins")?,
+            KeyCode::Null => f.write_str("null")?,
+            KeyCode::Esc => f.write_str("esc")?,
+            KeyCode::Char('<') => f.write_str("lt")?,
+            KeyCode::Char('>') => f.write_str("gt")?,
+            KeyCode::Char('+') => f.write_str("plus")?,
+            KeyCode::Char('-') => f.write_str("minus")?,
+            KeyCode::Char(';') => f.write_str("semicolon")?,
+            KeyCode::Char('%') => f.write_str("percent")?,
+            KeyCode::F(i) => f.write_fmt(format_args!("F{}", i))?,
+            KeyCode::Char(c) => f.write_fmt(format_args!("{}", c))?,
+        };
+        Ok(())
+    }
+}
+
+impl std::str::FromStr for KeyEvent {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut tokens: Vec<_> = s.split('-').collect();
+        let code = match tokens.pop().ok_or_else(|| anyhow!("Missing key code"))? {
+            "backspace" => KeyCode::Backspace,
+            "space" => KeyCode::Char(' '),
+            "ret" => KeyCode::Enter,
+            "lt" => KeyCode::Char('<'),
+            "gt" => KeyCode::Char('>'),
+            "plus" => KeyCode::Char('+'),
+            "minus" => KeyCode::Char('-'),
+            "semicolon" => KeyCode::Char(';'),
+            "percent" => KeyCode::Char('%'),
+            "left" => KeyCode::Left,
+            "right" => KeyCode::Right,
+            "up" => KeyCode::Down,
+            "home" => KeyCode::Home,
+            "end" => KeyCode::End,
+            "pageup" => KeyCode::PageUp,
+            "pagedown" => KeyCode::PageDown,
+            "tab" => KeyCode::Tab,
+            "backtab" => KeyCode::BackTab,
+            "del" => KeyCode::Delete,
+            "ins" => KeyCode::Insert,
+            "null" => KeyCode::Null,
+            "esc" => KeyCode::Esc,
+            single if single.len() == 1 => KeyCode::Char(single.chars().next().unwrap()),
+            function if function.len() > 1 && function.starts_with('F') => {
+                let function: String = function.chars().skip(1).collect();
+                let function = str::parse::<u8>(&function)?;
+                (function > 0 && function < 13)
+                    .then(|| KeyCode::F(function))
+                    .ok_or_else(|| anyhow!("Invalid function key '{}'", function))?
+            }
+            invalid => return Err(anyhow!("Invalid key code '{}'", invalid)),
+        };
+
+        let mut modifiers = KeyModifiers::empty();
+        for token in tokens {
+            let flag = match token {
+                "S" => KeyModifiers::SHIFT,
+                "A" => KeyModifiers::ALT,
+                "C" => KeyModifiers::CONTROL,
+                _ => return Err(anyhow!("Invalid key modifier '{}-'", token)),
+            };
+
+            if modifiers.contains(flag) {
+                return Err(anyhow!("Repeated key modifier '{}-'", token));
+            }
+            modifiers.insert(flag);
+        }
+
+        Ok(KeyEvent { code, modifiers })
+    }
+}
+
+impl<'de> Deserialize<'de> for KeyEvent {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        s.parse().map_err(de::Error::custom)
+    }
+}
+
+impl From<event::KeyEvent> for KeyEvent {
+    fn from(event::KeyEvent { code, modifiers }: event::KeyEvent) -> KeyEvent {
+        KeyEvent { code, modifiers }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn parsing_unmodified_keys() {
+        assert_eq!(
+            str::parse::<KeyEvent>("backspace").unwrap(),
+            KeyEvent {
+                code: KeyCode::Backspace,
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("left").unwrap(),
+            KeyEvent {
+                code: KeyCode::Left,
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>(",").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char(','),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("w").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('w'),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("F12").unwrap(),
+            KeyEvent {
+                code: KeyCode::F(12),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+    }
+
+    #[test]
+    fn parsing_modified_keys() {
+        assert_eq!(
+            str::parse::<KeyEvent>("S-minus").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('-'),
+                modifiers: KeyModifiers::SHIFT
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("C-A-S-F12").unwrap(),
+            KeyEvent {
+                code: KeyCode::F(12),
+                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL | KeyModifiers::ALT
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("S-C-2").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('2'),
+                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL
+            }
+        );
+    }
+
+    #[test]
+    fn parsing_nonsensical_keys_fails() {
+        assert!(str::parse::<KeyEvent>("F13").is_err());
+        assert!(str::parse::<KeyEvent>("F0").is_err());
+        assert!(str::parse::<KeyEvent>("aaa").is_err());
+        assert!(str::parse::<KeyEvent>("S-S-a").is_err());
+        assert!(str::parse::<KeyEvent>("C-A-S-C-1").is_err());
+        assert!(str::parse::<KeyEvent>("FU").is_err());
+        assert!(str::parse::<KeyEvent>("123").is_err());
+        assert!(str::parse::<KeyEvent>("S--").is_err());
+    }
+}
diff --git a/helix-view/src/lib.rs b/helix-view/src/lib.rs
index 20613451..8b635700 100644
--- a/helix-view/src/lib.rs
+++ b/helix-view/src/lib.rs
@@ -3,14 +3,16 @@ pub mod macros;
 
 pub mod document;
 pub mod editor;
+pub mod input;
 pub mod register_selection;
 pub mod theme;
 pub mod tree;
 pub mod view;
 
-use slotmap::new_key_type;
-new_key_type! { pub struct DocumentId; }
-new_key_type! { pub struct ViewId; }
+slotmap::new_key_type! {
+    pub struct DocumentId;
+    pub struct ViewId;
+}
 
 pub use document::Document;
 pub use editor::Editor;