Add IPC config subcommand

This patch adds a new mechanism for changing configuration options
without editing the configuration file, by sending options to running
instances through `alacritty msg`.

Each window will load Alacritty's configuration file by default and then
accept IPC messages for config updates using the `alacritty msg config`
subcommand. By default all windows will be updated, individual windows
can be addressed using `alacritty msg config --window-id
"$ALACRITTY_WINDOW_ID"`.

Each option will replace the config's current value and cannot be reset
until Alacritty is restarted or the option is overwritten with a new
value.

Configuration options are passed in the format `field.subfield=value`,
where `value` is interpreted as yaml.

Closes #472.

1 files changed, 2 insertions, 2 deletions

diff --git a/alacritty_terminal/src/config/scrolling.rs b/alacritty_terminal/src/config/scrolling.rs
index 9a5a718c..f4e55787 100644
--- a/alacritty_terminal/src/config/scrolling.rs
+++ b/alacritty_terminal/src/config/scrolling.rs
@@ -1,7 +1,7 @@
 use serde::de::Error as SerdeError;
 use serde::{Deserialize, Deserializer};
 
-use alacritty_config_derive::ConfigDeserialize;
+use alacritty_config_derive::{ConfigDeserialize, SerdeReplace};
 
 /// Maximum scrollback amount configurable.
 pub const MAX_SCROLLBACK_LINES: u32 = 100_000;
@@ -31,7 +31,7 @@ impl Scrolling {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(SerdeReplace, Copy, Clone, Debug, PartialEq, Eq)]
 struct ScrollingHistory(u32);
 
 impl Default for ScrollingHistory {