Extract lua language support into an extension (#10437)

Release Notes:

- Extracted lua language support into an extension, and improved Lua
highlighting and completion label styling.

---------

Co-authored-by: Marshall <marshall@zed.dev>

extensions/lua/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "zed_lua"
+version = "0.0.1"
+edition = "2021"
+publish = false
+license = "Apache-2.0"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/lua.rs"
+crate-type = ["cdylib"]
+
+[dependencies]
+zed_extension_api = "0.0.6"

extensions/lua/LICENSE-APACHE

@@ -0,0 +1 @@
+../../LICENSE-APACHE

extensions/lua/extension.toml

@@ -0,0 +1,15 @@
+id = "lua"
+name = "Lua"
+description = "Lua support."
+version = "0.1.0"
+schema_version = 1
+authors = ["Kaylee Simmons <kay@the-simmons.net>"]
+repository = "https://github.com/zed-industries/zed"
+
+[language_servers.lua-language-server]
+name = "LuaLS"
+language = "Lua"
+
+[grammars.lua]
+repository = "https://github.com/tree-sitter-grammars/tree-sitter-lua"
+commit = "a24dab177e58c9c6832f96b9a73102a0cfbced4a"

extensions/lua/languages/lua/brackets.scm

@@ -0,0 +1,3 @@
+("[" @open "]" @close)
+("{" @open "}" @close)
+("(" @open ")" @close)

extensions/lua/languages/lua/config.toml

@@ -0,0 +1,13 @@
+name = "Lua"
+grammar = "lua"
+path_suffixes = ["lua"]
+line_comments = ["-- "]
+autoclose_before = ";:.,=}])>"
+brackets = [
+    { start = "{", end = "}", close = true, newline = true },
+    { start = "[", end = "]", close = true, newline = true },
+    { start = "(", end = ")", close = true, newline = true },
+    { start = "\"", end = "\"", close = true, newline = false, not_in = ["string"] },
+    { start = "'", end = "'", close = false, newline = false, not_in = ["string"] },
+]
+collapsed_placeholder = "--[ ... ]--"

extensions/lua/languages/lua/embedding.scm

@@ -0,0 +1,10 @@
+(
+    (comment)* @context
+    .
+    (function_declaration
+        "function" @name
+        name: (_) @name
+        (comment)* @collapse
+        body: (block) @collapse
+    ) @item
+)

extensions/lua/languages/lua/highlights.scm

@@ -0,0 +1,198 @@
+;; Keywords
+
+"return" @keyword
+
+[
+ "goto"
+ "in"
+ "local"
+] @keyword
+
+(break_statement) @keyword
+
+(do_statement
+[
+  "do"
+  "end"
+] @keyword)
+
+(while_statement
+[
+  "while"
+  "do"
+  "end"
+] @keyword)
+
+(repeat_statement
+[
+  "repeat"
+  "until"
+] @keyword)
+
+(if_statement
+[
+  "if"
+  "elseif"
+  "else"
+  "then"
+  "end"
+] @keyword)
+
+(elseif_statement
+[
+  "elseif"
+  "then"
+  "end"
+] @keyword)
+
+(else_statement
+[
+  "else"
+  "end"
+] @keyword)
+
+(for_statement
+[
+  "for"
+  "do"
+  "end"
+] @keyword)
+
+(function_declaration
+[
+  "function"
+  "end"
+] @keyword)
+
+(function_definition
+[
+  "function"
+  "end"
+] @keyword)
+
+;; Operators
+
+[
+ "and"
+ "not"
+ "or"
+] @operator
+
+[
+  "+"
+  "-"
+  "*"
+  "/"
+  "%"
+  "^"
+  "#"
+  "=="
+  "~="
+  "<="
+  ">="
+  "<"
+  ">"
+  "="
+  "&"
+  "~"
+  "|"
+  "<<"
+  ">>"
+  "//"
+  ".."
+] @operator
+
+;; Punctuations
+
+[
+  ";"
+  ":"
+  ","
+  "."
+] @punctuation.delimiter
+
+;; Brackets
+
+[
+ "("
+ ")"
+ "["
+ "]"
+ "{"
+ "}"
+] @punctuation.bracket
+
+;; Variables
+
+(identifier) @variable
+
+((identifier) @variable.special
+ (#eq? @variable.special "self"))
+
+(variable_list
+   attribute: (attribute
+     (["<" ">"] @punctuation.bracket
+      (identifier) @attribute)))
+
+;; Constants
+
+((identifier) @constant
+ (#match? @constant "^[A-Z][A-Z_0-9]*$"))
+
+(vararg_expression) @constant
+
+(nil) @constant.builtin
+
+[
+  (false)
+  (true)
+] @boolean
+
+;; Tables
+
+(field name: (identifier) @property)
+
+(dot_index_expression field: (identifier) @property)
+
+(table_constructor
+[
+  "{"
+  "}"
+] @constructor)
+
+;; Functions
+
+(parameters (identifier) @parameter)
+
+(function_call
+  name: [
+    (identifier) @function
+    (dot_index_expression field: (identifier) @function)
+  ])
+
+(function_declaration
+  name: [
+    (identifier) @function.definition
+    (dot_index_expression field: (identifier) @function.definition)
+  ])
+
+(method_index_expression method: (identifier) @function.method)
+
+(function_call
+  (identifier) @function.builtin
+  (#any-of? @function.builtin
+    ;; built-in functions in Lua 5.1
+    "assert" "collectgarbage" "dofile" "error" "getfenv" "getmetatable" "ipairs"
+    "load" "loadfile" "loadstring" "module" "next" "pairs" "pcall" "print"
+    "rawequal" "rawget" "rawset" "require" "select" "setfenv" "setmetatable"
+    "tonumber" "tostring" "type" "unpack" "xpcall"))
+
+;; Others
+
+(comment) @comment
+
+(hash_bang_line) @preproc
+
+(number) @number
+
+(string) @string

extensions/lua/languages/lua/indents.scm

@@ -0,0 +1,10 @@
+(if_statement "end" @end) @indent
+(do_statement "end" @end) @indent
+(while_statement "end" @end) @indent
+(for_statement "end" @end) @indent
+(repeat_statement "until" @end) @indent
+(function_declaration "end" @end) @indent
+
+(_ "[" "]" @end) @indent
+(_ "{" "}" @end) @indent
+(_ "(" ")" @end) @indent

extensions/lua/languages/lua/outline.scm

@@ -0,0 +1,3 @@
+(function_declaration
+    "function" @context
+    name: (_) @name) @item

extensions/lua/src/lua.rs

@@ -0,0 +1,158 @@
+use std::fs;
+use zed::lsp::CompletionKind;
+use zed::{CodeLabel, CodeLabelSpan, LanguageServerId};
+use zed_extension_api::{self as zed, Result};
+
+struct LuaExtension {
+    cached_binary_path: Option<String>,
+}
+
+impl LuaExtension {
+    fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<String> {
+        if let Some(path) = &self.cached_binary_path {
+            if fs::metadata(path).map_or(false, |stat| stat.is_file()) {
+                return Ok(path.clone());
+            }
+        }
+
+        if let Some(path) = worktree.which("lua-language-server") {
+            self.cached_binary_path = Some(path.clone());
+            return Ok(path);
+        }
+
+        zed::set_language_server_installation_status(
+            &language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let release = zed::latest_github_release(
+            "LuaLS/lua-language-server",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        )?;
+
+        let (platform, arch) = zed::current_platform();
+        let asset_name = format!(
+            "lua-language-server-{version}-{os}-{arch}.tar.gz",
+            version = release.version,
+            os = match platform {
+                zed::Os::Mac => "darwin",
+                zed::Os::Linux => "linux",
+                zed::Os::Windows => "win32",
+            },
+            arch = match arch {
+                zed::Architecture::Aarch64 => "arm64",
+                zed::Architecture::X8664 => "x86_64",
+                zed::Architecture::X86 => return Err("unsupported platform x86".into()),
+            },
+        );
+
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| format!("no asset found matching {:?}", asset_name))?;
+
+        let version_dir = format!("lua-language-server-{}", release.version);
+        let binary_path = format!("{version_dir}/bin/lua-language-server");
+
+        if !fs::metadata(&binary_path).map_or(false, |stat| stat.is_file()) {
+            zed::set_language_server_installation_status(
+                &language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+
+            zed::download_file(
+                &asset.download_url,
+                &version_dir,
+                zed::DownloadedFileType::GzipTar,
+            )
+            .map_err(|e| format!("failed to download file: {e}"))?;
+
+            let entries =
+                fs::read_dir(".").map_err(|e| format!("failed to list working directory {e}"))?;
+            for entry in entries {
+                let entry = entry.map_err(|e| format!("failed to load directory entry {e}"))?;
+                if entry.file_name().to_str() != Some(&version_dir) {
+                    fs::remove_dir_all(&entry.path()).ok();
+                }
+            }
+        }
+
+        self.cached_binary_path = Some(binary_path.clone());
+        Ok(binary_path)
+    }
+}
+
+impl zed::Extension for LuaExtension {
+    fn new() -> Self {
+        Self {
+            cached_binary_path: None,
+        }
+    }
+
+    fn language_server_command(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<zed::Command> {
+        Ok(zed::Command {
+            command: self.language_server_binary_path(language_server_id, worktree)?,
+            args: Default::default(),
+            env: Default::default(),
+        })
+    }
+
+    fn label_for_completion(
+        &self,
+        _language_server_id: &LanguageServerId,
+        completion: zed::lsp::Completion,
+    ) -> Option<CodeLabel> {
+        match completion.kind? {
+            CompletionKind::Method | CompletionKind::Function => {
+                let name_len = completion.label.find('(').unwrap_or(completion.label.len());
+                Some(CodeLabel {
+                    spans: vec![CodeLabelSpan::code_range(0..completion.label.len())],
+                    filter_range: (0..name_len).into(),
+                    code: completion.label,
+                })
+            }
+            CompletionKind::Field => Some(CodeLabel {
+                spans: vec![CodeLabelSpan::literal(
+                    completion.label.clone(),
+                    Some("property".into()),
+                )],
+                filter_range: (0..completion.label.len()).into(),
+                code: Default::default(),
+            }),
+            _ => None,
+        }
+    }
+
+    fn label_for_symbol(
+        &self,
+        _language_server_id: &LanguageServerId,
+        symbol: zed::lsp::Symbol,
+    ) -> Option<CodeLabel> {
+        let prefix = "let a = ";
+        let suffix = match symbol.kind {
+            zed::lsp::SymbolKind::Method => "()",
+            _ => "",
+        };
+        let code = format!("{prefix}{}{suffix}", symbol.name);
+        Some(CodeLabel {
+            spans: vec![CodeLabelSpan::code_range(
+                prefix.len()..code.len() - suffix.len(),
+            )],
+            filter_range: (0..symbol.name.len()).into(),
+            code,
+        })
+    }
+}
+
+zed::register_extension!(LuaExtension);