Configurable auto pairs (#1624)

* impl auto pairs config

Implements configuration for which pairs of tokens get auto completed.

In order to help with this, the logic for when *not* to auto complete
has been generalized from a specific hardcoded list of characters to
simply testing if the next/prev char is alphanumeric.

It is possible to configure a global list of pairs as well as at the
language level. The language config will take precedence over the
global config.

* rename AutoPair -> Pair

* clean up insert_char command

* remove Rc

* remove some explicit cloning with another impl

* fix lint

* review comments

* global auto-pairs = false takes precedence over language settings

* make clippy happy

* print out editor config on startup

* move auto pairs accessor into Document

* rearrange auto pair doc comment

* use pattern in Froms

2 files changed, 40 insertions, 6 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index f13338ba..671ceb75 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -1,4 +1,5 @@
 use anyhow::{anyhow, bail, Context, Error};
+use helix_core::auto_pairs::AutoPairs;
 use serde::de::{self, Deserialize, Deserializer};
 use serde::Serialize;
 use std::cell::Cell;
@@ -20,7 +21,7 @@ use helix_core::{
 };
 use helix_lsp::util::LspFormatting;
 
-use crate::{DocumentId, ViewId};
+use crate::{DocumentId, Editor, ViewId};
 
 /// 8kB of buffer space for encoding and decoding `Rope`s.
 const BUF_SIZE: usize = 8192;
@@ -98,7 +99,7 @@ pub struct Document {
     pub line_ending: LineEnding,
 
     syntax: Option<Syntax>,
-    // /// Corresponding language scope name. Usually `source.<lang>`.
+    /// Corresponding language scope name. Usually `source.<lang>`.
     pub(crate) language: Option<Arc<LanguageConfiguration>>,
 
     /// Pending changes since last history commit.
@@ -946,6 +947,28 @@ impl Document {
         self.diagnostics
             .sort_unstable_by_key(|diagnostic| diagnostic.range);
     }
+
+    /// Get the document's auto pairs. If the document has a recognized
+    /// language config with auto pairs configured, returns that;
+    /// otherwise, falls back to the global auto pairs config. If the global
+    /// config is false, then ignore language settings.
+    pub fn auto_pairs<'a>(&'a self, editor: &'a Editor) -> Option<&'a AutoPairs> {
+        let global_config = (editor.auto_pairs).as_ref();
+
+        // NOTE: If the user specifies the global auto pairs config as false, then
+        //       we want to disable it globally regardless of language settings
+        #[allow(clippy::question_mark)]
+        {
+            if global_config.is_none() {
+                return None;
+            }
+        }
+
+        match &self.language {
+            Some(lang) => lang.as_ref().auto_pairs.as_ref().or(global_config),
+            None => global_config,
+        }
+    }
 }
 
 impl Default for Document {
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index d44dc1c6..85d9be67 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -13,6 +13,7 @@ use futures_util::future;
 use futures_util::stream::select_all::SelectAll;
 use tokio_stream::wrappers::UnboundedReceiverStream;
 
+use log::debug;
 use std::{
     borrow::Cow,
     collections::{BTreeMap, HashMap},
@@ -29,7 +30,10 @@ use anyhow::{bail, Error};
 
 pub use helix_core::diagnostic::Severity;
 pub use helix_core::register::Registers;
-use helix_core::syntax;
+use helix_core::{
+    auto_pairs::AutoPairs,
+    syntax::{self, AutoPairConfig},
+};
 use helix_core::{Position, Selection};
 use helix_dap as dap;
 
@@ -98,8 +102,10 @@ pub struct Config {
     pub line_number: LineNumber,
     /// Middle click paste support. Defaults to true.
     pub middle_click_paste: bool,
-    /// Automatic insertion of pairs to parentheses, brackets, etc. Defaults to true.
-    pub auto_pairs: bool,
+    /// Automatic insertion of pairs to parentheses, brackets,
+    /// etc. Optionally, this can be a list of 2-tuples to specify a
+    /// global list of characters to pair. Defaults to true.
+    pub auto_pairs: AutoPairConfig,
     /// Automatic auto-completion, automatically pop up without user trigger. Defaults to true.
     pub auto_completion: bool,
     /// Time in milliseconds since last keypress before idle timers trigger. Used for autocompletion, set to 0 for instant. Defaults to 400ms.
@@ -217,7 +223,7 @@ impl Default for Config {
             },
             line_number: LineNumber::Absolute,
             middle_click_paste: true,
-            auto_pairs: true,
+            auto_pairs: AutoPairConfig::default(),
             auto_completion: true,
             idle_timeout: Duration::from_millis(400),
             completion_trigger_len: 2,
@@ -289,6 +295,7 @@ pub struct Editor {
     pub autoinfo: Option<Info>,
 
     pub config: Config,
+    pub auto_pairs: Option<AutoPairs>,
 
     pub idle_timer: Pin<Box<Sleep>>,
     pub last_motion: Option<Motion>,
@@ -312,6 +319,9 @@ impl Editor {
         config: Config,
     ) -> Self {
         let language_servers = helix_lsp::Registry::new();
+        let auto_pairs = (&config.auto_pairs).into();
+
+        debug!("Editor config: {config:#?}");
 
         // HAXX: offset the render area height by 1 to account for prompt/commandline
         area.height -= 1;
@@ -337,6 +347,7 @@ impl Editor {
             idle_timer: Box::pin(sleep(config.idle_timeout)),
             last_motion: None,
             config,
+            auto_pairs,
             exit_code: 0,
         }
     }