indent on typing dot. fixes #439

crates/ra_analysis/src/lib.rs

@@ -12,41 +12,39 @@ macro_rules! ctry {
     };
 }
 
-mod db;
-mod imp;
 mod completion;
+mod db;
 mod goto_defenition;
-mod symbol_index;
+mod imp;
 pub mod mock_analysis;
 mod runnables;
+mod symbol_index;
 
 mod extend_selection;
-mod syntax_highlighting;
 mod hover;
+mod syntax_highlighting;
 
 use std::{fmt, sync::Arc};
 
-use rustc_hash::FxHashMap;
-use ra_syntax::{SourceFileNode, TextRange, TextUnit, SmolStr, SyntaxKind};
+use ra_syntax::{SmolStr, SourceFileNode, SyntaxKind, TextRange, TextUnit};
 use ra_text_edit::TextEdit;
 use rayon::prelude::*;
 use relative_path::RelativePathBuf;
+use rustc_hash::FxHashMap;
 use salsa::ParallelDatabase;
 
-use crate::symbol_index::{SymbolIndex, FileSymbol};
+use crate::symbol_index::{FileSymbol, SymbolIndex};
 
 pub use crate::{
     completion::{CompletionItem, CompletionItemKind, InsertText},
     runnables::{Runnable, RunnableKind},
 };
-pub use ra_editor::{
-    Fold, FoldKind, HighlightedRange, LineIndex, StructureNode, Severity
-};
 pub use hir::FnSignatureInfo;
+pub use ra_editor::{Fold, FoldKind, HighlightedRange, LineIndex, Severity, StructureNode};
 
 pub use ra_db::{
-    Canceled, Cancelable, FilePosition, FileRange, LocalSyntaxPtr,
-    CrateGraph, CrateId, SourceRootId, FileId, SyntaxDatabase, FilesDatabase
+    Cancelable, Canceled, CrateGraph, CrateId, FileId, FilePosition, FileRange, FilesDatabase,
+    LocalSyntaxPtr, SourceRootId, SyntaxDatabase,
 };
 
 #[derive(Default)]
@@ -346,7 +344,7 @@ impl Analysis {
         let edit = ra_editor::on_enter(&file, position.offset)?;
         Some(SourceChange::from_local_edit(position.file_id, edit))
     }
-    /// Returns an edit which should be applied after `=` was typed. Primaraly,
+    /// Returns an edit which should be applied after `=` was typed. Primarily,
     /// this works when adding `let =`.
     // FIXME: use a snippet completion instead of this hack here.
     pub fn on_eq_typed(&self, position: FilePosition) -> Option<SourceChange> {
@@ -354,6 +352,12 @@ impl Analysis {
         let edit = ra_editor::on_eq_typed(&file, position.offset)?;
         Some(SourceChange::from_local_edit(position.file_id, edit))
     }
+    /// Returns an edit which should be applied when a dot ('.') is typed on a blank line, indenting the line appropriately.
+    pub fn on_dot_typed(&self, position: FilePosition) -> Option<SourceChange> {
+        let file = self.db.source_file(position.file_id);
+        let edit = ra_editor::on_dot_typed(&file, position.offset)?;
+        Some(SourceChange::from_local_edit(position.file_id, edit))
+    }
     /// Returns a tree representation of symbols in the file. Useful to draw a
     /// file outline.
     pub fn file_structure(&self, file_id: FileId) -> Vec<StructureNode> {

crates/ra_editor/src/lib.rs

@@ -16,7 +16,7 @@ pub use self::{
     line_index::{LineCol, LineIndex},
     line_index_utils::translate_offset_with_edit,
     structure::{file_structure, StructureNode},
-    typing::{join_lines, on_enter, on_eq_typed},
+    typing::{join_lines, on_enter, on_dot_typed, on_eq_typed},
     diagnostics::diagnostics
 };
 use ra_text_edit::TextEditBuilder;

crates/ra_editor/src/typing.rs

@@ -1,5 +1,6 @@
 use std::mem;
 
+use itertools::Itertools;
 use ra_syntax::{
     algo::{find_covering_node, find_leaf_at_offset, LeafAtOffset},
     ast,
@@ -9,9 +10,8 @@ use ra_syntax::{
     SyntaxNodeRef, TextRange, TextUnit,
 };
 use ra_text_edit::text_utils::contains_offset_nonstrict;
-use itertools::Itertools;
 
-use crate::{find_node_at_offset, TextEditBuilder, LocalEdit};
+use crate::{find_node_at_offset, LocalEdit, TextEditBuilder};
 
 pub fn join_lines(file: &SourceFileNode, range: TextRange) -> LocalEdit {
     let range = if range.is_empty() {
@@ -136,6 +136,27 @@ pub fn on_eq_typed(file: &SourceFileNode, offset: TextUnit) -> Option<LocalEdit>
     })
 }
 
+pub fn on_dot_typed(file: &SourceFileNode, offset: TextUnit) -> Option<LocalEdit> {
+    let before_dot_offset = offset - TextUnit::of_char('.');
+
+    let whitespace = find_leaf_at_offset(file.syntax(), before_dot_offset)
+        .left_biased()
+        .and_then(ast::Whitespace::cast)?;
+
+    // whitespace found just left of the dot
+    // TODO: indent is always 4 spaces now. A better heuristic could look on the previous line(s)
+    let indent = "    ".to_string();
+
+    let cursor_position = offset + TextUnit::of_str(&indent);;
+    let mut edit = TextEditBuilder::default();
+    edit.insert(before_dot_offset, indent);
+    Some(LocalEdit {
+        label: "indent dot".to_string(),
+        edit: edit.finish(),
+        cursor_position: Some(cursor_position),
+    })
+}
+
 fn remove_newline(
     edit: &mut TextEditBuilder,
     node: SyntaxNodeRef,
@@ -283,7 +304,9 @@ fn compute_ws(left: SyntaxNodeRef, right: SyntaxNodeRef) -> &'static str {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::test_utils::{add_cursor, check_action, extract_offset, extract_range, assert_eq_text};
+    use crate::test_utils::{
+        add_cursor, assert_eq_text, check_action, extract_offset, extract_range,
+    };
 
     fn check_join_lines(before: &str, after: &str) {
         check_action(before, after, |file, offset| {
@@ -614,6 +637,31 @@ fn foo() {
         // ");
     }
 
+    #[test]
+    fn test_on_dot_typed() {
+        fn do_check(before: &str, after: &str) {
+            let (offset, before) = extract_offset(before);
+            let file = SourceFileNode::parse(&before);
+            let result = on_dot_typed(&file, offset).unwrap();
+            let actual = result.edit.apply(&before);
+            assert_eq_text!(after, &actual);
+        }
+        do_check(
+            r"
+    pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
+        self.child_impl(db, name)
+        .<|>
+    }
+",
+            r"
+    pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
+        self.child_impl(db, name)
+            .
+    }
+",
+        );
+    }
+
     #[test]
     fn test_on_enter() {
         fn apply_on_enter(before: &str) -> Option<String> {

crates/ra_lsp_server/src/main_loop/handlers.rs

@@ -2,15 +2,16 @@ use std::collections::HashMap;
 
 use gen_lsp_server::ErrorCode;
 use languageserver_types::{
-    CodeActionResponse, Command, Diagnostic,
-    DiagnosticSeverity, DocumentSymbol, Documentation, FoldingRange, FoldingRangeKind,
-    FoldingRangeParams, Location, MarkupContent, MarkupKind, MarkedString, Position,
-    PrepareRenameResponse, RenameParams, SymbolInformation, TextDocumentIdentifier, TextEdit,
-    Range, WorkspaceEdit, ParameterInformation, ParameterLabel, SignatureInformation, Hover,
-    HoverContents, DocumentFormattingParams, DocumentHighlight,
+    CodeActionResponse, Command, Diagnostic, DiagnosticSeverity, DocumentFormattingParams,
+    DocumentHighlight, DocumentSymbol, Documentation, FoldingRange, FoldingRangeKind,
+    FoldingRangeParams, Hover, HoverContents, Location, MarkedString, MarkupContent, MarkupKind,
+    ParameterInformation, ParameterLabel, Position, PrepareRenameResponse, Range, RenameParams,
+    SignatureInformation, SymbolInformation, TextDocumentIdentifier, TextEdit, WorkspaceEdit,
 };
-use ra_analysis::{FileId, FoldKind, Query, RunnableKind, FileRange, FilePosition, Severity};
-use ra_syntax::{TextUnit, text_utils::intersect};
+use ra_analysis::{
+    FileId, FilePosition, FileRange, FoldKind, Query, RunnableKind, Severity, SourceChange,
+};
+use ra_syntax::{text_utils::intersect, TextUnit};
 use ra_text_edit::text_utils::contains_offset_nonstrict;
 use rustc_hash::FxHashMap;
 use serde_json::to_value;
@@ -92,7 +93,7 @@ pub fn handle_on_type_formatting(
     world: ServerWorld,
     params: req::DocumentOnTypeFormattingParams,
 ) -> Result<Option<Vec<TextEdit>>> {
-    if params.ch != "=" {
+    if params.ch != "=" || params.ch != "." {
         return Ok(None);
     }
 
@@ -102,9 +103,17 @@ pub fn handle_on_type_formatting(
         file_id,
         offset: params.position.conv_with(&line_index),
     };
-    let edits = match world.analysis().on_eq_typed(position) {
-        None => return Ok(None),
-        Some(mut action) => action
+
+    let analysis: Vec<Box<Fn(FilePosition) -> Option<SourceChange>>> = vec![
+        Box::new(|pos| world.analysis().on_eq_typed(pos)),
+        Box::new(|pos| world.analysis().on_dot_typed(pos)),
+    ];
+
+    // try all analysis until one succeeds
+    for ana in analysis {
+        if let Some(mut action) = ana(position) {
+            return Ok(Some(
+                action
                     .source_file_edits
                     .pop()
                     .unwrap()
@@ -113,8 +122,11 @@ pub fn handle_on_type_formatting(
                     .iter()
                     .map_conv_with(&line_index)
                     .collect(),
-    };
-    Ok(Some(edits))
+            ));
+        }
+    }
+
+    return Ok(None);
 }
 
 pub fn handle_document_symbol(