h2000 · h2000 · Jan 18, 2026 · Jan 17, 2026 · Jan 18, 2026
diff --git a/README.md b/README.md
@@ -1,27 +1,94 @@
 # Roc lang support for Zed
 
+> **Note:** This branch (`use-new-roc-lsp`) uses a fork of tree-sitter-roc with modern Roc syntax support. It is not ready to merge until the changes land upstream at [faldor20/tree-sitter-roc](https://github.com/faldor20/tree-sitter-roc).
+
 An extension for Zed that adds Roc language support:
 
 - syntax highlighting through treesitter and
 - type tooltips, error marker, completion ... through the roc language server
 
-## Preqrequisites
+## Prerequisites
 
-- install roc from the [roc-lang](https://roc-lang.org) website
-- add roc and roc_language_server to your PATH
-- install Zed from the [Zed](https://zed.dev) website
+- Install Roc from the [roc-lang](https://roc-lang.org) website
+- Ensure the `roc` binary is in your PATH
+- Install Zed from the [Zed](https://zed.dev) website
 
 ## ROC
 
 - Website: [roc-lang.org](https://roc-lang.org)
-- Tree Sitter: [tree-sitter-roc](https://github.com/faldor20/tree-sitter-roc)
-- Language Server: [roc-language-server](https://github.com/roc-lang/roc/tree/main) included in nightly builds of the ROC compiler e.g. https://github.com/roc-lang/roc/releases/download/nightly/roc_nightly-macos_apple_silicon-latest.tar.gz, the roc_language_server binary should be included in PATH.
+- Tree Sitter: [tree-sitter-roc](https://github.com/lukewilliamboswell/tree-sitter-roc)
+- Language Server: This extension uses the new experimental LSP integrated into the `roc` CLI via `roc experimental-lsp`.
 
 ## Development
 
+### Installing the Dev Extension
+
+1. Open Zed's command palette (Cmd+Shift+P / Ctrl+Shift+P)
+2. Run "zed: install dev extension"
+3. Select this repository folder
+4. Click "Rebuild" if prompted
+
+**Note:** The version shown in Zed's Extensions panel may display the marketplace version (e.g., v0.0.6) even when the dev extension is active. This is a Zed caching behavior when the extension ID matches a marketplace extension.
+
+### Verifying the Dev Extension is Running
+
+Check Zed's logs (Command palette → "zed: open log file") and look for:
+```
+compiling Rust extension /path/to/your/zed-roc
+```
+
+If the path points to your local repository (not `~/Library/Application Support/Zed/extensions/installed/roc`), the dev extension is active.
+
+### Key Files
+
+- `extension.toml` - Extension manifest (id, version, grammar source, language config)
+- `languages/roc/config.toml` - Language configuration (file extensions, comments, brackets)
+- `languages/roc/*.scm` - Tree-sitter queries (highlights, indents, etc.)
+- `grammars/roc/` - Git clone of tree-sitter-roc (must match repository in extension.toml)
+
+### Updating the Tree-sitter Grammar
+
+The `grammars/roc/` directory must be a git clone of the repository specified in `extension.toml`. To update:
+
+1. Update the commit hash in `extension.toml` under `[grammars.roc]`
+2. Update the grammar submodule:
+   ```sh
+   cd grammars/roc
+   git fetch origin
+   git checkout <commit-hash>
+   ```
+3. Sync query files: `cp grammars/roc/queries/*.scm languages/roc/`
+4. Delete cached wasm to force recompilation: `rm grammars/roc.wasm`
+5. In Zed, click "Rebuild" on the extension
+
+### Troubleshooting
+
+**Extension not detecting .roc files:**
+- Check Zed logs for errors (Command palette → "zed: open log file")
+- Ensure `languages = ["languages/roc"]` is in `extension.toml`
+
+**Conflict with marketplace version:**
+- Uninstall the marketplace Roc extension first
+- If uninstall doesn't work, quit Zed and manually edit the extensions index.json to remove "roc" entries
+- Zed stores extensions in:
+  - macOS: `~/Library/Application Support/Zed/extensions/`
+  - Linux: `~/.local/share/zed/extensions/`
+
+**Grammar compilation errors:**
+- Ensure `grammars/roc/` is a git clone of the repository URL in `extension.toml`
+- The git remote origin must match the repository URL exactly
+
+### Useful Commands
+
 ```sh
-~/Library/Application\ Support/Zed/extensions/installed/
-less ~/Library/Logs/Zed/Zed.log
+# Sync query files from grammar to languages
+cp grammars/roc/queries/*.scm languages/roc/
+
+# Clean build artifacts
+rm -f grammars/roc.wasm extension.wasm
+
+# Check Zed logs (macOS)
+tail -f ~/Library/Logs/Zed/Zed.log | grep -i roc
 ```
 
 ![Zed Example](https://github.com/h2000/zed-roc/assets/187650/1ec0cda3-3679-4223-bc5e-3272babde364)
diff --git a/extension.toml b/extension.toml
@@ -1,14 +1,15 @@
 id = "roc"
 name = "Roc"
 description = "Roc language support for Zed"
-version = "0.0.6"
+version = "0.1.0"
 schema_version = 1
 authors = ["Alf Richter <kuehlboxen.vorgemisch0e@icloud.com>"]
 repository = "https://github.com/h2000/zed-roc"
+languages = ["languages/roc"]
 
 [grammars.roc]
-repository = "https://github.com/faldor20/tree-sitter-roc"
-commit = "6ea64b6434a45472bd87b0772fd84a017de0a557"
+repository = "https://github.com/lukewilliamboswell/tree-sitter-roc"
+commit = "80b6bbe1bab45396db0943db410b97e6f4579801"
 
 [language_servers.roc]
 language = "Roc"

diff --git a/justfile b/justfile
@@ -1,11 +1,15 @@
-update-tree-sitter:
-    -rm languages/roc/*.scm
-    cd ../tree-sitter-roc && git pullr
-    cp -v ../tree-sitter-roc/queries/*.scm languages/roc
+# Sync query files from tree-sitter-roc to languages/roc
+sync-queries:
+    cp -v grammars/roc/queries/*.scm languages/roc/
 
-clean:
-    -rm -rf grammars
-    -rm -f extension.wasm
+# Update grammar to a specific commit and sync queries
+update-grammar COMMIT:
+    cd grammars/roc && git fetch origin && git checkout {{COMMIT}}
+    just sync-queries
+    rm -f grammars/roc.wasm
+    @echo "Done. Click 'Rebuild' in Zed to recompile the grammar."
 
-update-extension:
-    cd ../zed-roc-extensions && git pullr && cd extensions/roc && git pullr
+# Clean build artifacts
+clean:
+    rm -f grammars/roc.wasm
+    rm -f extension.wasm
diff --git a/languages/roc/highlights.scm b/languages/roc/highlights.scm
@@ -10,8 +10,9 @@
 ;; opinion: typedefs cross into documentation and should be
 ;; highlighted differently from normal code
 
-(opaque_type_def (_ (concrete_type) @type.definition))
+(nominal_type_def (_ (concrete_type) @type.definition))
 (function_type (arrow) @punctuation.delimiter.structural.typedef)
+(function_type (effect_arrow) @punctuation.delimiter.structural.typedef)
 
 (parenthesized_type ["(" ")"] @punctuation.bracket.typedef)
 (tuple_type ["(" ")"] @punctuation.bracket.typedef)
@@ -24,14 +25,8 @@
 (record_field_type ":" @punctuation.delimiter.typedef)
 
 (record_field_type (field_name) @variable.other.enum.typedef)
-(ability_chain "&" @operator.typedef)
-
-(where_implements _
-  (where) @type.keyword
-  (identifier) @type.parameter
-  (implements) @type.keyword
-  (ability_chain) @type.parameter)
-
+(where_clause
+  (where) @type.keyword)
 
 ((concrete_type) @type.builtin
   (#match? @type.builtin "^(Bool|Str|Num|List|Result|Dict|Set|Dec)"))
@@ -50,8 +45,10 @@
 "?"
 (arrow)
 (back_arrow)
-(backslash)
 ] @punctuation.delimiter.structural
+
+; Lambda pipes
+(anon_fun_expr "|" @punctuation.delimiter.structural)
 (bang_expr "!" @punctuation.delimiter.structural)
 [
   ","
@@ -79,18 +76,18 @@
 
 [
   "if"
-  "then"
   "else"
 ] @keyword.control.conditional
 
 [
-(implements)
-(when)
-(is)
+"match"
 "as"
 (to)
 ] @keyword.control.roc
 
+; Match expression fat arrow
+(match_branch "=>" @punctuation.delimiter.structural)
+
 ;----headers-----
 
 [
@@ -154,8 +151,6 @@
 (function_call_expr
   caller: (field_access_expr (identifier)@function .))
 
-(bin_op_expr (operator "|>")@operator(variable_expr(identifier)@function))
-
 ;----function arguments----
 
 (argument_patterns(identifier_pattern
@@ -167,7 +162,7 @@
 (argument_patterns(_(_(_(_(_(identifier_pattern(identifier)@variable.parameter)))))))
 
 ; pattern captures
-(when_is_branch pattern: (_ (identifier_pattern (identifier) @variable.parameter)))
+(match_branch pattern: (_ (identifier_pattern (identifier) @variable.parameter)))
 (range_pattern (identifier) @variable.parameter)
 
 
@@ -200,6 +195,7 @@
 
 (string)@string
 (multiline_string)@string
+(line_string)@string
 (char) @constant.character
 (escape_char)@constant.character.escape
 

diff --git a/languages/roc/locals.scm b/languages/roc/locals.scm
@@ -20,10 +20,10 @@
 (exposes_list(ident)@local.reference)
 (import_expr(as)(module)@local.definition)
 
-(opaque_type_def(apply_type(concrete_type)@local.definition))
+(nominal_type_def(apply_type(concrete_type)@local.definition))
 (alias_type_def(apply_type(concrete_type)@local.definition))
 
-(when_is_branch pattern: (_ (identifier_pattern (identifier) @local.definition)))
+(match_branch pattern: (_ (identifier_pattern (identifier) @local.definition)))
 (range_pattern (identifier) @local.definition)
 
 (identifier)@local.reference

diff --git a/languages/roc/textobjects.scm b/languages/roc/textobjects.scm
@@ -24,7 +24,7 @@
 [
   (annotation_type_def ) @class.inside
   (alias_type_def ) @class.inside
-  (opaque_type_def ) @class.inside
+  (nominal_type_def ) @class.inside
 ] @class.around
 
 (apply_type_arg) @parameter.inside

diff --git a/src/lib.rs b/src/lib.rs
@@ -12,14 +12,14 @@ impl zed::Extension for RocExtension {
         _config: &zed::LanguageServerId,
         worktree: &zed::Worktree,
     ) -> Result<zed::Command> {
-        let binary_name = "roc_language_server";
+        let binary_name = "roc";
         let path = worktree
             .which(binary_name)
             .ok_or_else(|| format!("{binary_name} executable not found in $PATH"))?;
 
         Ok(zed::Command {
             command: path,
-            args: vec![],
+            args: vec!["experimental-lsp".to_string()],
             env: Default::default(),
         })
     }