ide: folding range support

crates/squawk_ide/src/lib.rs

@@ -8,6 +8,7 @@ pub mod db;
 pub mod document_symbols;
 pub mod expand_selection;
 pub mod find_references;
+pub mod folding_ranges;
 mod generated;
 pub mod goto_definition;
 pub mod hover;

crates/squawk_server/src/lib.rs

@@ -6,20 +6,20 @@ use lsp_types::{
     CodeAction, CodeActionKind, CodeActionOptions, CodeActionOrCommand, CodeActionParams,
     CodeActionProviderCapability, CodeActionResponse, Command, CompletionOptions, CompletionParams,
     CompletionResponse, Diagnostic, DidChangeTextDocumentParams, DidCloseTextDocumentParams,
-    DidOpenTextDocumentParams, DocumentSymbol, DocumentSymbolParams, GotoDefinitionParams,
-    GotoDefinitionResponse, Hover, HoverContents, HoverParams, HoverProviderCapability,
-    InitializeParams, InlayHint, InlayHintKind, InlayHintLabel, InlayHintLabelPart,
-    InlayHintParams, LanguageString, Location, MarkedString, OneOf, PublishDiagnosticsParams,
-    ReferenceParams, SelectionRangeParams, SelectionRangeProviderCapability, ServerCapabilities,
-    SymbolKind, TextDocumentSyncCapability, TextDocumentSyncKind, Url, WorkDoneProgressOptions,
-    WorkspaceEdit,
+    DidOpenTextDocumentParams, DocumentSymbol, DocumentSymbolParams, FoldingRange,
+    FoldingRangeProviderCapability, GotoDefinitionParams, GotoDefinitionResponse, Hover,
+    HoverContents, HoverParams, HoverProviderCapability, InitializeParams, InlayHint,
+    InlayHintKind, InlayHintLabel, InlayHintLabelPart, InlayHintParams, LanguageString, Location,
+    MarkedString, OneOf, PublishDiagnosticsParams, ReferenceParams, SelectionRangeParams,
+    SelectionRangeProviderCapability, ServerCapabilities, SymbolKind, TextDocumentSyncCapability,
+    TextDocumentSyncKind, Url, WorkDoneProgressOptions, WorkspaceEdit,
     notification::{
         DidChangeTextDocument, DidCloseTextDocument, DidOpenTextDocument, Notification as _,
         PublishDiagnostics,
     },
     request::{
-        CodeActionRequest, Completion, DocumentSymbolRequest, GotoDefinition, HoverRequest,
-        InlayHintRequest, References, Request, SelectionRangeRequest,
+        CodeActionRequest, Completion, DocumentSymbolRequest, FoldingRangeRequest, GotoDefinition,
+        HoverRequest, InlayHintRequest, References, Request, SelectionRangeRequest,
     },
 };
 use rowan::TextRange;
@@ -30,6 +30,7 @@ use squawk_ide::completion::completion;
 use squawk_ide::db::{Database, File, line_index, parse};
 use squawk_ide::document_symbols::{DocumentSymbolKind, document_symbols};
 use squawk_ide::find_references::find_references;
+use squawk_ide::folding_ranges::folding_ranges;
 use squawk_ide::goto_definition::goto_definition;
 use squawk_ide::hover::hover;
 use squawk_ide::inlay_hints::inlay_hints;
@@ -119,6 +120,7 @@ pub fn run() -> Result<()> {
         hover_provider: Some(HoverProviderCapability::Simple(true)),
         inlay_hint_provider: Some(OneOf::Left(true)),
         document_symbol_provider: Some(OneOf::Left(true)),
+        folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
         completion_provider: Some(CompletionOptions {
             resolve_provider: Some(false),
             trigger_characters: Some(vec![".".to_owned()]),
@@ -183,6 +185,9 @@ fn main_loop(connection: Connection, params: serde_json::Value) -> Result<()> {
                     DocumentSymbolRequest::METHOD => {
                         handle_document_symbol(&connection, req, &file_system)?;
                     }
+                    FoldingRangeRequest::METHOD => {
+                        handle_folding_range(&connection, req, &file_system)?;
+                    }
                     Completion::METHOD => {
                         handle_completion(&connection, req, &file_system)?;
                     }
@@ -450,6 +455,33 @@ fn handle_document_symbol(
     Ok(())
 }
 
+fn handle_folding_range(
+    connection: &Connection,
+    req: lsp_server::Request,
+    file_system: &impl FileSystem,
+) -> Result<()> {
+    let params: lsp_types::FoldingRangeParams = serde_json::from_value(req.params)?;
+    let uri = params.text_document.uri;
+
+    let db = file_system.db();
+    let file = file_system.file(&uri).unwrap();
+    let line_idx = line_index(db, file);
+
+    let lsp_folds: Vec<FoldingRange> = folding_ranges(db, file)
+        .into_iter()
+        .map(|fold| lsp_utils::folding_range(&line_idx, fold))
+        .collect();
+
+    let resp = Response {
+        id: req.id,
+        result: Some(serde_json::to_value(&lsp_folds).unwrap()),
+        error: None,
+    };
+
+    connection.sender.send(Message::Response(resp))?;
+    Ok(())
+}
+
 fn handle_selection_range(
     connection: &Connection,
     req: lsp_server::Request,

crates/squawk_server/src/lsp_utils.rs

@@ -2,8 +2,12 @@ use std::{collections::HashMap, ops::Range};
 
 use line_index::{LineIndex, TextRange, TextSize};
 use log::warn;
-use lsp_types::{CodeAction, CodeActionKind, Url, WorkspaceEdit};
+use lsp_types::{
+    CodeAction, CodeActionKind, FoldingRange, FoldingRangeKind as LspFoldingRangeKind, Url,
+    WorkspaceEdit,
+};
 use squawk_ide::code_actions::ActionKind;
+use squawk_ide::folding_ranges::{Fold, FoldKind};
 
 fn text_range(index: &LineIndex, range: lsp_types::Range) -> Option<TextRange> {
     let start = offset(index, range.start)?;
@@ -143,6 +147,23 @@ pub(crate) fn range(line_index: &LineIndex, range: TextRange) -> lsp_types::Rang
     )
 }
 
+pub(crate) fn folding_range(line_index: &LineIndex, fold: Fold) -> FoldingRange {
+    let start = line_index.line_col(fold.range.start());
+    let end = line_index.line_col(fold.range.end());
+    let kind = match fold.kind {
+        FoldKind::Comment => Some(LspFoldingRangeKind::Comment),
+        _ => Some(LspFoldingRangeKind::Region),
+    };
+    FoldingRange {
+        start_line: start.line,
+        start_character: Some(start.col),
+        end_line: end.line,
+        end_character: Some(end.col),
+        kind,
+        collapsed_text: None,
+    }
+}
+
 // base on rust-analyzer's
 // see: https://github.com/rust-lang/rust-analyzer/blob/3816d0ae53c19fe75532a8b41d8c546d94246b53/crates/rust-analyzer/src/lsp/utils.rs#L168C1-L168C1
 pub(crate) fn apply_incremental_changes(

crates/squawk_syntax/src/ast.rs

@@ -28,6 +28,7 @@ mod generated;
 mod node_ext;
 mod nodes;
 mod support;
+mod token_ext;
 mod traits;
 
 use std::marker::PhantomData;

crates/squawk_syntax/src/ast/token_ext.rs

@@ -0,0 +1,44 @@
+use crate::ast::{self, AstToken};
+
+impl ast::Whitespace {
+    pub fn spans_multiple_lines(&self) -> bool {
+        let text = self.text();
+        text.find('\n')
+            .is_some_and(|idx| text[idx + 1..].contains('\n'))
+    }
+}
+
+impl ast::Comment {
+    pub fn kind(&self) -> CommentKind {
+        CommentKind::from_text(self.text())
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum CommentKind {
+    Line,
+    Block,
+}
+
+impl CommentKind {
+    const BY_PREFIX: [(&'static str, CommentKind); 3] = [
+        ("/**/", CommentKind::Block),
+        ("/*", CommentKind::Block),
+        ("--", CommentKind::Line),
+    ];
+    pub(crate) fn from_text(text: &str) -> CommentKind {
+        let &(_prefix, kind) = CommentKind::BY_PREFIX
+            .iter()
+            .find(|&(prefix, _kind)| text.starts_with(prefix))
+            .unwrap();
+        kind
+    }
+
+    pub fn is_line(self) -> bool {
+        self == CommentKind::Line
+    }
+
+    pub fn is_block(self) -> bool {
+        self == CommentKind::Block
+    }
+}

crates/xtask/src/codegen.rs

@@ -533,6 +533,7 @@ fn lower(grammar: &Grammar) -> AstSrc {
         ("Null", "NULL_KW"),
         ("String", "STRING"),
         ("Comment", "COMMENT"),
+        ("Whitespace", "WHITESPACE"),
     ];
     let mut res = AstSrc {
         tokens,