Add runtime language configuration (#1794) (#1866)

* Add runtime language configuration (#1794)

* Add set-language typable command to change the language of current buffer.
* Add completer for available language options.

* Update set-language to refresh language server as well

* Add language id based config lookup on `syntax::Loader`.
* Add `Document::set_language3` to set programming language based on language
  id.
* Update `Editor::refresh_language_server` to try language detection only if
  language is not already set.

* Remove language detection from Editor::refresh_language_server

* Move document language detection to where the scratch buffer is saved.
* Rename Document::set_language3 to Document::set_language_by_language_id.

* Remove unnecessary clone in completers::language

1 files changed, 21 insertions, 0 deletions

diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index a90debdb..2dca870b 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -298,6 +298,27 @@ pub mod completers {
         })
     }
 
+    pub fn language(editor: &Editor, input: &str) -> Vec<Completion> {
+        let matcher = Matcher::default();
+
+        let mut matches: Vec<_> = editor
+            .syn_loader
+            .language_configs()
+            .filter_map(|config| {
+                matcher
+                    .fuzzy_match(&config.language_id, input)
+                    .map(|score| (&config.language_id, score))
+            })
+            .collect();
+
+        matches.sort_unstable_by_key(|(_language, score)| Reverse(*score));
+
+        matches
+            .into_iter()
+            .map(|(language, _score)| ((0..), language.clone().into()))
+            .collect()
+    }
+
     pub fn directory(_editor: &Editor, input: &str) -> Vec<Completion> {
         filename_impl(input, |entry| {
             let is_dir = entry.file_type().map_or(false, |entry| entry.is_dir());