Only auto-format for certain languages

Fixes #53
Fixes #207

helix-core/src/syntax.rs

@@ -28,8 +28,8 @@ pub struct LanguageConfiguration {
     pub file_types: Vec<String>, // filename ends_with? <Gemfile, rb, etc>
     pub roots: Vec<String>,      // these indicate project roots <.git, Cargo.toml>
 
-    // pub path: PathBuf,
-    // root_path for tree-sitter (^)
+    #[serde(default)]
+    pub auto_format: bool,
 
     // content_regex
     // injection_regex

helix-term/src/commands.rs

@@ -966,7 +966,13 @@ mod cmd {
             editor.set_error("cannot write a buffer without a filename".to_string());
             return;
         }
+        let autofmt = doc
+            .language_config()
+            .map(|config| config.auto_format)
+            .unwrap_or_default();
+        if autofmt {
             doc.format(view.id); // TODO: merge into save
+        }
         tokio::spawn(doc.save());
     }
 

languages.toml

@@ -4,6 +4,7 @@ scope = "source.rust"
 injection-regex = "rust"
 file-types = ["rs"]
 roots = []
+auto-format = true
 
 language-server = { command = "rust-analyzer" }
 indent = { tab-width = 4, unit = "    " }
@@ -61,6 +62,7 @@ scope = "source.go"
 injection-regex = "go"
 file-types = ["go"]
 roots = ["Gopkg.toml", "go.mod"]
+auto-format = true
 
 language-server = { command = "gopls" }
 # TODO: gopls needs utf-8 offsets?