Parse remap action

example/test.yml

@@ -33,6 +33,10 @@ keymap:
       # SKK hack for Chrome
       C-j: C-m
 
+      C-m:
+        remap:
+          C-j: a
+
   - name: Default (Nocturn, etc.)
     wm_class:
       not: [Google-chrome, Slack, Gnome-terminal, jetbrains-idea]

src/config/action.rs

@@ -1,18 +1,78 @@
-use crate::config::keypress::KeyPress;
+use crate::config::keypress::{parse_keypress, KeyPress};
+use std::collections::HashMap;
 
-use serde::Deserialize;
+use crate::config::actions::Actions;
+use serde::de;
+use serde::de::{MapAccess, Visitor};
+use serde::{Deserialize, Deserializer};
 use std::fmt::{Debug, Formatter};
 
-#[derive(Deserialize)]
-#[serde(untagged)]
+#[derive(Debug)]
 pub enum Action {
     KeyPress(KeyPress),
+    Remap(HashMap<KeyPress, Vec<Action>>),
 }
 
-impl Debug for Action {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Action::KeyPress(key_press) => key_press.fmt(f),
+impl<'de> Deserialize<'de> for Action {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct ActionVisitor;
+
+        impl<'de> Visitor<'de> for ActionVisitor {
+            type Value = Action;
+
+            fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
+                formatter.write_str("string or map")
+            }
+
+            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                let keypress = parse_keypress(value).map_err(de::Error::custom)?;
+                Ok(Action::KeyPress(keypress))
+            }
+
+            fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
+            where
+                M: MapAccess<'de>,
+            {
+                let key = map.next_key::<String>()?;
+                let action = match key.as_deref() {
+                    Some("remap") => {
+                        let mut action: HashMap<KeyPress, Vec<Action>> = HashMap::new();
+                        let remap = map.next_value::<HashMap<KeyPress, Actions>>()?;
+                        for (keypress, actions) in remap.into_iter() {
+                            let actions = match actions {
+                                Actions::Action(action) => vec![action],
+                                Actions::Actions(actions) => actions,
+                            };
+                            action.insert(keypress, actions);
+                        }
+                        Action::Remap(action)
+                    }
+                    Some(action) => {
+                        return serde_error::<Self::Value, M>(&format!(
+                            "unexpected action '{}'",
+                            action
+                        ))
+                    }
+                    None => return serde_error::<Self::Value, M>("missing action"),
+                };
+                Ok(action)
+            }
         }
+
+        deserializer.deserialize_any(ActionVisitor)
     }
 }
+
+fn serde_error<'de, V, M>(message: &str) -> Result<V, M::Error>
+where
+    M: MapAccess<'de>,
+{
+    let error: Box<dyn std::error::Error> = message.into();
+    Err(error).map_err(de::Error::custom)
+}

src/config/actions.rs

@@ -0,0 +1,57 @@
+use crate::config::action::Action;
+use crate::config::keypress::parse_keypress;
+use serde::de;
+use serde::de::{value, MapAccess, SeqAccess, Visitor};
+use serde::{Deserialize, Deserializer};
+use std::fmt::Formatter;
+
+// Used only for deserializing Vec<Action>
+pub enum Actions {
+    Action(Action),
+    Actions(Vec<Action>),
+}
+
+impl<'de> Deserialize<'de> for Actions {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct ActionsVisitor;
+
+        impl<'de> Visitor<'de> for ActionsVisitor {
+            type Value = Actions;
+
+            fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
+                formatter.write_str("strings or maps")
+            }
+
+            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                let keypress = parse_keypress(value).map_err(de::Error::custom)?;
+                Ok(Actions::Action(Action::KeyPress(keypress)))
+            }
+
+            fn visit_seq<S>(self, seq: S) -> Result<Self::Value, S::Error>
+            where
+                S: SeqAccess<'de>,
+            {
+                let actions: Vec<Action> =
+                    Deserialize::deserialize(value::SeqAccessDeserializer::new(seq))?;
+                Ok(Actions::Actions(actions))
+            }
+
+            fn visit_map<M>(self, map: M) -> Result<Self::Value, M::Error>
+            where
+                M: MapAccess<'de>,
+            {
+                let action: Action =
+                    Deserialize::deserialize(value::MapAccessDeserializer::new(map))?;
+                Ok(Actions::Action(action))
+            }
+        }
+
+        deserializer.deserialize_any(ActionsVisitor)
+    }
+}

src/config/keymap.rs

@@ -1,10 +1,12 @@
 use crate::config::action::Action;
+use crate::config::actions::Actions;
 use crate::config::keypress::KeyPress;
 use crate::config::wm_class::WMClass;
 use serde::de::{MapAccess, Visitor};
 use serde::{Deserialize, Deserializer};
 use std::collections::HashMap;
 use std::fmt;
+use std::fmt::Formatter;
 
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
@@ -21,17 +23,10 @@ where
 {
     struct KeymapRemap;
 
-    #[derive(Deserialize)]
-    #[serde(untagged)]
-    enum Actions {
-        Action(Action),
-        Actions(Vec<Action>),
-    }
-
     impl<'de> Visitor<'de> for KeymapRemap {
         type Value = HashMap<KeyPress, Vec<Action>>;
 
-        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        fn expecting(&self, formatter: &mut Formatter) -> fmt::Result {
             formatter.write_str("map from string to strings or maps")
         }
 

src/config/keypress.rs

@@ -33,10 +33,10 @@ impl<'de> Deserialize<'de> for KeyPress {
             type Value = KeyPress;
 
             fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
-                formatter.write_str("string or map")
+                formatter.write_str("string")
             }
 
-            fn visit_str<E>(self, value: &str) -> Result<KeyPress, E>
+            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
             where
                 E: de::Error,
             {
@@ -48,7 +48,7 @@ impl<'de> Deserialize<'de> for KeyPress {
     }
 }
 
-fn parse_keypress(input: &str) -> Result<KeyPress, Box<dyn error::Error>> {
+pub fn parse_keypress(input: &str) -> Result<KeyPress, Box<dyn error::Error>> {
     let keys: Vec<&str> = input.split("-").collect();
     if let Some((key, modifiers)) = keys.split_last() {
         let mut shift = false;

src/config/mod.rs

@@ -1,4 +1,5 @@
 mod action;
+mod actions;
 mod key;
 mod keymap;
 mod keypress;