Complete words from open buffers (#13206)

helix-core/src/completion.rs

@@ -16,6 +16,7 @@ pub struct CompletionItem {
 pub enum CompletionProvider {
     Lsp(LanguageServerId),
     Path,
+    Word,
 }
 
 impl From<LanguageServerId> for CompletionProvider {

helix-core/src/syntax/config.rs

@@ -7,6 +7,7 @@ use serde::{ser::SerializeSeq as _, Deserialize, Serialize};
 use std::{
     collections::{HashMap, HashSet},
     fmt::{self, Display},
+    num::NonZeroU8,
     path::PathBuf,
     str::FromStr,
 };
@@ -60,6 +61,8 @@ pub struct LanguageConfiguration {
 
     /// If set, overrides `editor.path-completion`.
     pub path_completion: Option<bool>,
+    /// If set, overrides `editor.word-completion`.
+    pub word_completion: Option<WordCompletion>,
 
     #[serde(default)]
     pub diagnostic_severity: Severity,
@@ -572,6 +575,13 @@ pub struct SoftWrap {
     pub wrap_at_text_width: Option<bool>,
 }
 
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(default, rename_all = "kebab-case", deny_unknown_fields)]
+pub struct WordCompletion {
+    pub enable: Option<bool>,
+    pub trigger_length: Option<NonZeroU8>,
+}
+
 fn deserialize_regex<'de, D>(deserializer: D) -> Result<Option<rope::Regex>, D::Error>
 where
     D: serde::Deserializer<'de>,

helix-core/src/transaction.rs

@@ -19,6 +19,16 @@ pub enum Operation {
     Insert(Tendril),
 }
 
+impl Operation {
+    /// The number of characters affected by the operation.
+    pub fn len_chars(&self) -> usize {
+        match self {
+            Self::Retain(n) | Self::Delete(n) => *n,
+            Self::Insert(s) => s.chars().count(),
+        }
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum Assoc {
     Before,