feat: support formatters (#113)

* feat: supports formatter

* feat: supports dynamic configuration and typstfmt

* fix: test

Cargo.toml

@@ -53,15 +53,17 @@ reflexo = { version = "0.5.0-rc2", default-features = false, features = [
 typst-ts-core = { version = "0.5.0-rc2", default-features = false }
 typst-ts-compiler = { version = "0.5.0-rc2" }
 typst-preview = { version = "0.11.3" }
+typstyle = "0.11.4"
+typstfmt_lib = { git = "https://github.com/astrale-sharp/typstfmt", tag = "0.2.7" }
 
 lsp-server = "0.7.6"
 lsp-types = { version = "=0.95.0", features = ["proposed"] }
 crossbeam-channel = "0.5.12"
 
-clap = { version = "4.4", features = ["derive", "env", "unicode", "wrap_help"] }
+clap = { version = "4.5", features = ["derive", "env", "unicode", "wrap_help"] }
 clap_builder = { version = "4", features = ["string"] }
-clap_complete = "4.4"
+clap_complete = "4.5"
-clap_complete_fig = "4.4"
+clap_complete_fig = "4.5"
 clap_mangen = { version = "0.2.15" }
 vergen = { version = "8.2.5", features = [
     "build",

crates/tinymist-query/src/lib.rs

@@ -109,6 +109,7 @@ pub trait StatefulRequest {
 
 #[allow(missing_docs)]
 mod polymorphic {
+    use lsp_types::TextEdit;
     use serde::{Deserialize, Serialize};
 
     use super::prelude::*;
@@ -150,6 +151,12 @@ mod polymorphic {
         pub path: PathBuf,
     }
 
+    #[derive(Debug, Clone)]
+    pub struct FormattingRequest {
+        /// The path of the document to get semantic tokens for.
+        pub path: PathBuf,
+    }
+
     #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
     pub enum FoldRequestFeature {
         PinnedFirst,
@@ -176,6 +183,7 @@ mod polymorphic {
         Symbol(SymbolRequest),
         SemanticTokensFull(SemanticTokensFullRequest),
         SemanticTokensDelta(SemanticTokensDeltaRequest),
+        Formatting(FormattingRequest),
         FoldingRange(FoldingRangeRequest),
         SelectionRange(SelectionRangeRequest),
     }
@@ -200,6 +208,7 @@ mod polymorphic {
                 CompilerQueryRequest::Symbol(..) => Mergable,
                 CompilerQueryRequest::SemanticTokensFull(..) => ContextFreeUnique,
                 CompilerQueryRequest::SemanticTokensDelta(..) => ContextFreeUnique,
+                CompilerQueryRequest::Formatting(..) => ContextFreeUnique,
                 CompilerQueryRequest::FoldingRange(..) => ContextFreeUnique,
                 CompilerQueryRequest::SelectionRange(..) => ContextFreeUnique,
             }
@@ -223,6 +232,7 @@ mod polymorphic {
                 CompilerQueryRequest::Symbol(..) => return None,
                 CompilerQueryRequest::SemanticTokensFull(req) => &req.path,
                 CompilerQueryRequest::SemanticTokensDelta(req) => &req.path,
+                CompilerQueryRequest::Formatting(req) => &req.path,
                 CompilerQueryRequest::FoldingRange(req) => &req.path,
                 CompilerQueryRequest::SelectionRange(req) => &req.path,
             })
@@ -247,6 +257,7 @@ mod polymorphic {
         Symbol(Option<Vec<SymbolInformation>>),
         SemanticTokensFull(Option<SemanticTokensResult>),
         SemanticTokensDelta(Option<SemanticTokensFullDeltaResult>),
+        Formatting(Option<Vec<TextEdit>>),
         FoldingRange(Option<Vec<FoldingRange>>),
         SelectionRange(Option<Vec<SelectionRange>>),
     }

crates/tinymist/Cargo.toml

@@ -42,6 +42,9 @@ typst-render.workspace = true
 typst-timing.workspace = true
 typst-assets = { workspace = true, features = ["fonts"] }
 
+typstyle.workspace = true
+typstfmt_lib.workspace = true
+
 typst-ts-core = { workspace = true, default-features = false, features = [
     "flat-vector",
     "vector-bbox",

crates/tinymist/src/actor.rs

@@ -1,6 +1,7 @@
 //! Bootstrap actors for Tinymist.
 
 pub mod cluster;
+mod formatting;
 pub mod render;
 pub mod typ_client;
 pub mod typ_server;
@@ -14,6 +15,7 @@ use typst_ts_compiler::{
 use typst_ts_core::config::compiler::EntryState;
 
 use self::{
+    formatting::run_format_thread,
     render::{ExportActor, ExportConfig},
     typ_client::{CompileClientActor, CompileDriver, CompileHandler},
     typ_server::CompileServerActor,
@@ -24,6 +26,8 @@ use crate::{
     TypstLanguageServer,
 };
 
+pub use formatting::{FormattingConfig, FormattingRequest};
+
 type CompileDriverInner = CompileDriverImpl<LspWorld>;
 
 impl CompileServer {
@@ -113,4 +117,20 @@ impl TypstLanguageServer {
     ) -> CompileClientActor {
         self.primary.server(diag_group, entry, inputs)
     }
+
+    pub fn run_format_thread(&mut self) {
+        if self.format_thread.is_some() {
+            log::error!("formatting thread already started");
+            return;
+        }
+
+        let (tx_req, rx_req) = crossbeam_channel::unbounded();
+        self.format_thread = Some(tx_req.clone());
+
+        let client = self.client.clone();
+        let mode = self.config.formatter;
+        std::thread::spawn(move || {
+            run_format_thread(FormattingConfig { mode, width: 120 }, rx_req, client)
+        });
+    }
 }

crates/tinymist/src/actor/formatting.rs

@@ -0,0 +1,91 @@
+use lsp_server::RequestId;
+use lsp_types::{Position, Range, TextEdit};
+use typst::syntax::Source;
+
+use crate::{result_to_response_, FormatterMode, LspHost, LspResult, TypstLanguageServer};
+
+#[derive(Debug, Clone)]
+pub struct FormattingConfig {
+    pub mode: FormatterMode,
+    pub width: u32,
+}
+
+pub enum FormattingRequest {
+    ChangeConfig(FormattingConfig),
+    Formatting((RequestId, Source)),
+}
+
+pub fn run_format_thread(
+    init_c: FormattingConfig,
+    rx_req: crossbeam_channel::Receiver<FormattingRequest>,
+    client: LspHost<TypstLanguageServer>,
+) {
+    type FmtFn = Box<dyn Fn(Source) -> LspResult<Option<Vec<TextEdit>>>>;
+    let compile = |c: FormattingConfig| -> FmtFn {
+        log::info!("formatting thread with config: {c:#?}");
+        match c.mode {
+            FormatterMode::Typstyle => {
+                let cw = c.width as usize;
+                let f: FmtFn = Box::new(move |e: Source| {
+                    let res = typstyle_core::pretty_print(e.text(), cw);
+                    Ok(Some(vec![TextEdit {
+                        new_text: res,
+                        range: Range::new(
+                            Position {
+                                line: 0,
+                                character: 0,
+                            },
+                            Position {
+                                line: u32::MAX,
+                                character: u32::MAX,
+                            },
+                        ),
+                    }]))
+                });
+                f
+            }
+            FormatterMode::Typstfmt => {
+                let config = typstfmt_lib::Config {
+                    max_line_length: 120,
+                    ..typstfmt_lib::Config::default()
+                };
+                let f: FmtFn = Box::new(move |e: Source| {
+                    let res = typstfmt_lib::format(e.text(), config);
+                    Ok(Some(vec![TextEdit {
+                        new_text: res,
+                        range: Range::new(
+                            Position {
+                                line: 0,
+                                character: 0,
+                            },
+                            Position {
+                                line: u32::MAX,
+                                character: u32::MAX,
+                            },
+                        ),
+                    }]))
+                });
+                f
+            }
+            FormatterMode::Disable => {
+                let f: FmtFn = Box::new(|_| Ok(None));
+                f
+            }
+        }
+    };
+
+    let mut f: FmtFn = compile(init_c);
+    while let Ok(req) = rx_req.recv() {
+        match req {
+            FormattingRequest::ChangeConfig(c) => f = compile(c),
+            FormattingRequest::Formatting((id, source)) => {
+                let res = f(source);
+                if let Ok(response) = result_to_response_(id, res) {
+                    client.respond(response);
+                }
+            }
+        }
+    }
+
+    log::info!("formatting thread did shut down");
+}

crates/tinymist/src/server/lsp.rs

@@ -37,7 +37,7 @@ use crossbeam_channel::select;
 use crossbeam_channel::Receiver;
 use futures::future::BoxFuture;
 use log::{error, info, trace, warn};
-use lsp_server::{ErrorCode, Message, Notification, Request, ResponseError};
+use lsp_server::{ErrorCode, Message, Notification, Request, RequestId, ResponseError};
 use lsp_types::notification::Notification as NotificationTrait;
 use lsp_types::request::{GotoDeclarationParams, GotoDeclarationResponse, WorkspaceConfiguration};
 use lsp_types::*;
@@ -60,6 +60,7 @@ use typst_ts_core::{error::prelude::*, ImmutPath};
 use super::lsp_init::*;
 use crate::actor::render::ExportConfig;
 use crate::actor::typ_client::CompileClientActor;
+use crate::actor::{FormattingConfig, FormattingRequest};
 use crate::compiler::{CompileServer, CompileServerArgs};
 use crate::compiler_init::CompilerConstConfig;
 use crate::harness::{InitializedLspDriver, LspHost};
@@ -83,14 +84,20 @@ impl fmt::Display for Event {
     }
 }
 
-struct Cancelled;
+pub(crate) struct Cancelled;
 
 type LspMethod<Res> = fn(srv: &mut TypstLanguageServer, args: JsonValue) -> LspResult<Res>;
 type LspHandler<Req, Res> = fn(srv: &mut TypstLanguageServer, args: Req) -> LspResult<Res>;
 
+/// Returns Ok(Some()) -> Already responded
+/// Returns Ok(None) -> Need to respond none
+/// Returns Err(..) -> Need t o respond error
+type LspRawHandler =
+    fn(srv: &mut TypstLanguageServer, args: (RequestId, JsonValue)) -> LspResult<Option<()>>;
+
 type ExecuteCmdMap = HashMap<&'static str, LspHandler<Vec<JsonValue>, JsonValue>>;
 type NotifyCmdMap = HashMap<&'static str, LspMethod<()>>;
-type RegularCmdMap = HashMap<&'static str, LspMethod<JsonValue>>;
+type RegularCmdMap = HashMap<&'static str, LspRawHandler>;
 
 macro_rules! exec_fn {
     ($ty: ty, Self::$method: ident, $($arg_key:ident),+ $(,)?) => {{
@@ -99,15 +106,44 @@ macro_rules! exec_fn {
     }};
 }
 
+macro_rules! request_fn_ {
+    ($desc: ty, Self::$method: ident) => {
+        (<$desc>::METHOD, {
+            const E: LspRawHandler = |this, (req_id, req)| {
+                let req: <$desc as lsp_types::request::Request>::Params =
+                    serde_json::from_value(req).unwrap(); // todo: soft unwrap
+                this.$method(req_id, req)
+            };
+            E
+        })
+    };
+}
+
 macro_rules! request_fn {
     ($desc: ty, Self::$method: ident) => {
         (<$desc>::METHOD, {
-            const E: LspMethod<JsonValue> = |this, req| {
+            const E: LspRawHandler = |this, (req_id, req)| {
                 let req: <$desc as lsp_types::request::Request>::Params =
                     serde_json::from_value(req).unwrap(); // todo: soft unwrap
-                let res = this.$method(req)?;
+                let res = this
-                let res = serde_json::to_value(res).unwrap(); // todo: soft unwrap
+                    .$method(req)
-                Ok(res)
+                    .map(|res| serde_json::to_value(res).unwrap()); // todo: soft unwrap
+
+                if let Ok(response) = result_to_response(req_id, res) {
+                    this.client.respond(response);
+                }
+
+                // todo: cancellation
+                // Err(e) => match e.downcast::<Cancelled>() {
+                //     Ok(cancelled) => return Err(cancelled),
+                //     Err(e) => lsp_server::Response::new_err(
+                //         id,
+                //         lsp_server::ErrorCode::InternalError as i32,
+                //         e.to_string(),
+                //     ),
+                // },
+
+                Ok(Some(()))
             };
             E
         })
@@ -152,6 +188,7 @@ pub struct TypstLanguageServer {
     /// Whether the server is shutting down.
     pub shutdown_requested: bool,
     pub sema_tokens_registered: Option<bool>,
+    pub formatter_registered: Option<bool>,
 
     // Configurations
     /// User configuration from the editor.
@@ -175,6 +212,7 @@ pub struct TypstLanguageServer {
     pub primary: CompileServer,
     pub main: Option<CompileClientActor>,
     pub tokens_ctx: SemanticTokenContext,
+    pub format_thread: Option<crossbeam_channel::Sender<FormattingRequest>>,
 }
 
 /// Getters and the main loop.
@@ -200,6 +238,7 @@ impl TypstLanguageServer {
             }),
             shutdown_requested: false,
             sema_tokens_registered: None,
+            formatter_registered: None,
             config: Default::default(),
             const_config: args.const_config,
             compile_opts: args.compile_opts,
@@ -212,6 +251,7 @@ impl TypstLanguageServer {
             pinning: false,
             main: None,
             tokens_ctx,
+            format_thread: None,
         }
     }
 
@@ -238,6 +278,7 @@ impl TypstLanguageServer {
             request_fn!(SemanticTokensFullDeltaRequest, Self::semantic_tokens_full_delta),
             request_fn!(DocumentSymbolRequest, Self::document_symbol),
             // Sync for low latency
+            request_fn_!(Formatting, Self::formatting),
             request_fn!(SelectionRangeRequest, Self::selection_range),
             // latency insensitive
             request_fn!(InlayHintRequest, Self::inlay_hint),
@@ -287,6 +328,15 @@ impl InitializedLspDriver for TypstLanguageServer {
             }
         }
 
+        if self.const_config().doc_fmt_dynamic_registration
+            && self.config.formatter != FormatterMode::Disable
+        {
+            let err = self.react_formatter_changes(true);
+            if let Err(err) = err {
+                error!("could not register formatter for initialization: {err}");
+            }
+        }
+
         if self.const_config().cfg_change_registration {
             trace!("setting up to request config change notifications");
 
@@ -394,30 +444,13 @@ impl TypstLanguageServer {
             return;
         };
 
-        let result = handler(self, req.params);
+        let res = handler(self, (req.id.clone(), req.params));
-
+        if matches!(res, Ok(Some(()))) {
-        if let Ok(response) = result_to_response(req.id, result) {
+            return;
-            self.client.respond(response);
         }
 
-        // todo: cancellation
+        if let Ok(response) = result_to_response_(req.id, res) {
-        // Err(e) => match e.downcast::<Cancelled>() {
+            self.client.respond(response);
-        //     Ok(cancelled) => return Err(cancelled),
-        //     Err(e) => lsp_server::Response::new_err(
-        //         id,
-        //         lsp_server::ErrorCode::InternalError as i32,
-        //         e.to_string(),
-        //     ),
-        // },
-        fn result_to_response(
-            id: lsp_server::RequestId,
-            result: Result<JsonValue, ResponseError>,
-        ) -> Result<lsp_server::Response, Cancelled> {
-            let res = match result {
-                Ok(resp) => lsp_server::Response::new_ok(id, resp),
-                Err(e) => lsp_server::Response::new_err(id, e.code, e.message),
-            };
-            Ok(res)
         }
     }
 
@@ -481,6 +514,53 @@ impl TypstLanguageServer {
 
         res
     }
+
+    fn react_formatter_changes(&mut self, enable: bool) -> anyhow::Result<()> {
+        if !self.const_config().doc_fmt_dynamic_registration {
+            trace!("skip dynamic register formatter by config");
+            return Ok(());
+        }
+
+        const FORMATTING_REGISTRATION_ID: &str = "formatting";
+        const DOCUMENT_FORMATTING_METHOD_ID: &str = "textDocument/formatting";
+
+        pub fn get_formatting_registration() -> Registration {
+            Registration {
+                id: FORMATTING_REGISTRATION_ID.to_owned(),
+                method: DOCUMENT_FORMATTING_METHOD_ID.to_owned(),
+                register_options: None,
+            }
+        }
+
+        pub fn get_formatting_unregistration() -> Unregistration {
+            Unregistration {
+                id: FORMATTING_REGISTRATION_ID.to_owned(),
+                method: DOCUMENT_FORMATTING_METHOD_ID.to_owned(),
+            }
+        }
+
+        let res = match (enable, self.formatter_registered) {
+            (true, None | Some(false)) => {
+                trace!("registering formatter");
+                self.client
+                    .register_capability(vec![get_formatting_registration()])
+                    .context("could not register formatter")
+            }
+            (false, Some(true)) => {
+                trace!("unregistering formatter");
+                self.client
+                    .unregister_capability(vec![get_formatting_unregistration()])
+                    .context("could not unregister formatter")
+            }
+            (true, Some(true)) | (false, None | Some(false)) => Ok(()),
+        };
+
+        if res.is_ok() {
+            self.formatter_registered = Some(enable);
+        }
+
+        res
+    }
 }
 
 /// Trait implemented by language server backends.
@@ -823,6 +903,22 @@ impl TypstLanguageServer {
             }
         }
 
+        if config.formatter != self.config.formatter {
+            let err = self.react_formatter_changes(self.config.formatter != FormatterMode::Disable);
+            if let Err(err) = err {
+                error!("could not change formatter config: {err}");
+            }
+            if let Some(f) = &self.format_thread {
+                let err = f.send(FormattingRequest::ChangeConfig(FormattingConfig {
+                    mode: self.config.formatter,
+                    width: 120,
+                }));
+                if let Err(err) = err {
+                    error!("could not change formatter config: {err}");
+                }
+            }
+        }
+
         // todo: watch changes of the root path
 
         Ok(())
@@ -929,6 +1025,26 @@ impl TypstLanguageServer {
         run_query!(self.SemanticTokensDelta(path, previous_result_id))
     }
 
+    fn formatting(
+        &self,
+        req_id: RequestId,
+        params: DocumentFormattingParams,
+    ) -> LspResult<Option<()>> {
+        if matches!(self.config.formatter, FormatterMode::Disable) {
+            return Ok(None);
+        }
+
+        let path = as_path(params.text_document);
+        self.query_source(&path, |source| {
+            if let Some(f) = &self.format_thread {
+                f.send(FormattingRequest::Formatting((req_id, source.clone())))?;
+            }
+
+            Ok(Some(()))
+        })
+        .map_err(|e| internal_error(format!("could not format document: {e}")))
+    }
+
     fn inlay_hint(&self, params: InlayHintParams) -> LspResult<Option<Vec<InlayHint>>> {
         let path = as_path(params.text_document);
         let range = params.range;
@@ -998,3 +1114,31 @@ pub fn method_not_found() -> ResponseError {
         data: None,
     }
 }
+
+pub(crate) fn result_to_response_<T: Serialize>(
+    id: lsp_server::RequestId,
+    result: Result<T, ResponseError>,
+) -> Result<lsp_server::Response, Cancelled> {
+    let res = match result {
+        Ok(resp) => {
+            let resp = serde_json::to_value(resp);
+            match resp {
+                Ok(resp) => lsp_server::Response::new_ok(id, resp),
+                Err(e) => return result_to_response(id, Err(internal_error(e.to_string()))),
+            }
+        }
+        Err(e) => lsp_server::Response::new_err(id, e.code, e.message),
+    };
+    Ok(res)
+}
+
+fn result_to_response(
+    id: lsp_server::RequestId,
+    result: Result<JsonValue, ResponseError>,
+) -> Result<lsp_server::Response, Cancelled> {
+    let res = match result {
+        Ok(resp) => lsp_server::Response::new_ok(id, resp),
+        Err(e) => lsp_server::Response::new_err(id, e.code, e.message),
+    };
+    Ok(res)
+}

crates/tinymist/src/server/lsp_init.rs

@@ -24,15 +24,17 @@ use crate::{
 // LocationLink[] even if the client does not report the
 // textDocument.definition.linkSupport capability.
 
-/// The mode of the experimental formatter.
+/// The mode of the formatter.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Deserialize)]
 #[serde(rename_all = "camelCase")]
-pub enum ExperimentalFormatterMode {
+pub enum FormatterMode {
-    /// Disable the experimental formatter.
+    /// Disable the formatter.
     #[default]
     Disable,
-    /// Enable the experimental formatter.
+    /// Use `typstyle` formatter.
-    Enable,
+    Typstyle,
+    /// Use `typstfmt` formatter.
+    Typstfmt,
 }
 
 /// The mode of PDF/SVG/PNG export.
@@ -83,7 +85,7 @@ const CONFIG_ITEMS: &[&str] = &[
     "exportPdf",
     "rootPath",
     "semanticTokens",
-    "experimentalFormatterMode",
+    "formatterMode",
     "typstExtraArgs",
 ];
 
@@ -95,7 +97,7 @@ pub struct Config {
     /// Dynamic configuration for semantic tokens.
     pub semantic_tokens: SemanticTokensMode,
     /// Dynamic configuration for the experimental formatter.
-    pub formatter: ExperimentalFormatterMode,
+    pub formatter: FormatterMode,
 }
 
 impl Config {
@@ -153,8 +155,8 @@ impl Config {
         }
 
         let formatter = update
-            .get("experimentalFormatterMode")
+            .get("formatterMode")
-            .map(ExperimentalFormatterMode::deserialize)
+            .map(FormatterMode::deserialize)
             .and_then(Result::ok);
         if let Some(formatter) = formatter {
             self.formatter = formatter;
@@ -354,6 +356,8 @@ impl Init {
         service.primary.config = config.compile.clone();
         service.config = config;
 
+        service.run_format_thread();
+
         let cluster_actor = CompileClusterActor {
             host: self.host.clone(),
             diag_rx,
@@ -383,8 +387,11 @@ impl Init {
             _ => None,
         };
 
+        //  if !cc.doc_fmt_dynamic_registration
         let document_formatting_provider = match service.config.formatter {
-            ExperimentalFormatterMode::Enable if !cc.doc_fmt_dynamic_registration => {
+            FormatterMode::Typstyle | FormatterMode::Typstfmt
+                if !cc.doc_fmt_dynamic_registration =>
+            {
                 Some(OneOf::Left(true))
             }
             _ => None,
@@ -480,7 +487,7 @@ mod tests {
             "exportPdf": "onSave",
             "rootPath": root_path,
             "semanticTokens": "enable",
-            "experimentalFormatterMode": "enable",
+            "formatterMode": "typstyle",
             "typstExtraArgs": ["--root", root_path]
         });
 
@@ -490,7 +497,7 @@ mod tests {
         assert_eq!(config.compile.export_pdf, ExportMode::OnSave);
         assert_eq!(config.compile.root_path, Some(PathBuf::from(root_path)));
         assert_eq!(config.semantic_tokens, SemanticTokensMode::Enable);
-        assert_eq!(config.formatter, ExperimentalFormatterMode::Enable);
+        assert_eq!(config.formatter, FormatterMode::Typstyle);
         assert_eq!(
             config.compile.typst_extra_args,
             Some(CompileExtraOpts {

crates/tinymist/src/state.rs

@@ -1,6 +1,6 @@
 //! Bootstrap actors for Tinymist.
 
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 use ::typst::{diag::FileResult, syntax::Source};
 use anyhow::anyhow;
@@ -162,16 +162,13 @@ macro_rules! run_query {
 }
 
 macro_rules! query_source {
-    ($self:ident, $method:ident, $req:expr) => {{
+    ($self:ident, $method:ident, $req:expr) => {
-        let path: ImmutPath = $req.path.clone().into();
+        $self.query_source(&$req.path.clone(), |source| {
-        let snapshot = $self.memory_changes.get(&path);
+            let enc = $self.const_config.position_encoding;
-        let snapshot = snapshot.ok_or_else(|| anyhow!("file missing {:?}", path))?;
+            let res = $req.request(&source, enc);
-        let source = snapshot.content.clone();
+            Ok(CompilerQueryResponse::$method(res))
-
+        })
-        let enc = $self.const_config.position_encoding;
+    };
-        let res = $req.request(&source, enc);
-        Ok(CompilerQueryResponse::$method(res))
-    }};
 }
 
 macro_rules! query_tokens_cache {
@@ -201,6 +198,18 @@ macro_rules! query_world {
 }
 
 impl TypstLanguageServer {
+    pub fn query_source<T>(
+        &self,
+        p: &Path,
+        f: impl FnOnce(Source) -> anyhow::Result<T>,
+    ) -> anyhow::Result<T> {
+        let path: ImmutPath = p.into();
+        let snapshot = self.memory_changes.get(&path);
+        let snapshot = snapshot.ok_or_else(|| anyhow!("file missing {:?}", path))?;
+        let source = snapshot.content.clone();
+        f(source)
+    }
+
     pub fn query(&self, query: CompilerQueryRequest) -> anyhow::Result<CompilerQueryResponse> {
         use CompilerQueryRequest::*;
 
@@ -254,6 +263,7 @@ impl TypstLanguageServer {
             FoldingRange(..)
             | SelectionRange(..)
             | SemanticTokensDelta(..)
+            | Formatting(..)
             | DocumentSymbol(..)
             | SemanticTokensFull(..) => unreachable!(),
         }

editors/vscode/package.json

@@ -121,18 +121,20 @@
                     "default": "off",
                     "description": "Traces the communication between VS Code and the language server."
                 },
-                "tinymist.experimentalFormatterMode": {
+                "tinymist.formatterMode": {
                     "title": "Enable Experimental Formatter",
-                    "description": "The extension can format Typst files using typstfmt (experimental).",
+                    "description": "The extension can format Typst files using typstfmt or typstyle.",
                     "type": "string",
                     "default": "disable",
                     "enum": [
                         "disable",
-                        "enable"
+                        "typstyle",
+                        "typstfmt"
                     ],
                     "enumDescriptions": [
                         "Formatter is not activated.",
-                        "Experimental formatter is activated."
+                        "Use typstyle formatter.",
+                        "Use typstfmt formatter."
                     ]
                 }
             }