feat: subscript access, setter methods, def self.method, heredoc fix (#21)

* feat: add subscript access, setter methods, def self.method, heredoc fix

Subscript expressions:
- arr[0], hash[:key], matrix[i][j] via SubscriptExpression
- Subscript assignment: arr[0] = 42, HASH[key] ||= []

Method definition improvements:
- Setter methods: def name=(val) ... end
- Class methods: def self.method(args) ... end (with and without parens)

Heredoc vs left-shift fix:
- Bare identifier heredocs (<<FILE) now reject non-whitespace after
  the delimiter on the opening line, preventing <<File.expand_path()
  from being misread as a heredoc

Real-world accuracy improvement:
- Devise: 98.0% → 99.1%
- All 7 repos above 95%

88 tests passing (5 new).

* fix: improve indentation deindent on end/else/elsif/rescue keywords

Indentation rules now check context.textAfter for closing keywords.
When typing `end`, `else`, `elsif`, `when`, `rescue`, `ensure` on a
new line inside a block, the line deindents to align with the opening
keyword (def, class, if, begin, etc.).

Previously the indent functions always added one unit regardless of
what was being typed, so `end` would stay indented until manually
adjusted.

* feat: restore hash symbol-key shorthand and fix indentation

Hash shorthand:
- {name: "Alice", age: 30} works again
- Moved Symbol from inline token to external tokenizer (symbolTokenizer)
  to eliminate : vs Symbol overlap with Block in expressions
- colonOp handles : in ternary and hash shorthand contexts
- Same pattern as /, <, % external tokenizers

Indentation fix:
- Indent functions now check context.textAfter for closing keywords
- Typing `end`, `else`, `elsif`, `when`, `rescue`, `ensure` immediately
  deindents to match the opening keyword
- After `end`, pressing enter starts at column 0 (not indented)
- Intermediate keywords (elsif, else, rescue) indent their bodies

89 tests passing.

* fix: rebuild indentation using indentService for incomplete code

The previous approach used indentNodeProp which depends on complete
parse tree nodes (MethodBody, ClassBody, etc.). These don't exist
while typing because the code is incomplete (no `end` yet).

New approach: text-based indentService that runs BEFORE tree-based
indentation. It checks the previous line's content:
- After def/class/module/if/while/etc. → indent one level
- After else/elsif/rescue/ensure/when → indent one level
- After end → stay at end's level
- On end/else/elsif/rescue/ensure → deindent to match opener
- Default → maintain previous line's indentation

Tree-based indentation (indentNodeProp) is kept only for bracket
delimited constructs ([], {}, ()) where delimitedIndent works well.

89 tests passing.

* fix: handle single-line forms and add comprehensive indent tests

Single-line forms like `class Foo; end`, `def foo; body; end`, and
endless methods `def foo(x) = x + 1` no longer incorrectly indent
the next line. Added 76 programmatic indentation tests covering
block openers, mid-block keywords, end alignment, nesting, modifier
forms, and real-world patterns. Also adds Tab key support and
Cmd+Shift+Enter for insert-line-above in the demo editor.

* feat: comprehensive indentation covering all 18 spec sections

Rewrote indent service to handle:
- Closing delimiters (}, ], )) via backward bracket scanning
- Continuation lines (trailing +, -, *, &&, ||, \, comma)
- Method chaining with leading dots (.bar, .baz)
- Assignment with block openers (x = if, x = case, @foo ||= begin)
- Chain-end detection: returns to base indent when chain/continuation ends
- Lambda/Proc blocks (-> (x) {, -> (x) do)
- Multi-line method def arguments

119 programmatic indent tests covering all 18 sections from the spec:
sections 1-8 (block openers, mid-block, end, delimiters, nesting,
modifiers, single-line), 9 (heredocs), 10 (continuations + chaining),
11 (lambdas), 12 (strings), 13 (assignment blocks), 14 (real-world),
15 (edge cases), 16 (when/in style), 17 (multi-line args), 18 (conditional assign).

* fix: Cmd+Shift+Enter inserts line with correct indentation

The insert-line-above keybinding now calculates the proper indent
level for the new line instead of always placing the cursor at
column 0. Also rebuilt demo bundle with latest indentation fixes.

* docs: update README with current test counts and remove fixed limitations

* chore: bump to 0.2.0, update accuracy benchmarks

Updated README with honest parse accuracy numbers from larger
real-world files (87.4% overall). Documented known limitations
from error pattern analysis. Bumped version to 0.2.0 for the
comprehensive indentation overhaul and edge case fixes.

* docs: add CHANGELOG for 0.1.0 and 0.2.0

Author: jeanpaulsio

CHANGELOG.md

@@ -0,0 +1,59 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+This project follows [Semantic Versioning](https://semver.org/).
+
+## [0.2.0] - 2026-03-26
+
+### Added
+
+- **Comprehensive indentation** — 119 programmatic tests covering all Ruby indent/dedent patterns:
+  - Block openers (def, class, module, if, unless, while, until, for, case, begin, do, braces)
+  - Mid-block keywords (else, elsif, when, rescue, ensure)
+  - Closing delimiters (}, ], ))
+  - Continuation lines (trailing +, -, &&, ||, \, comma)
+  - Method chaining with leading dots
+  - Assignment with block openers (`x = if`, `@foo ||= begin`)
+  - Modifier forms and single-line bodies (no indent change)
+  - Nested blocks at arbitrary depth
+- **Subscript expressions** — `arr[0]`, `hash[:key]`, `matrix[i][j]`
+- **Subscript assignment** — `hash[:key] = value`
+- **Setter method definitions** — `def name=(value)`
+- **Class method definitions** — `def self.method_name`
+- Tab key support in demo editor
+- Cmd+Shift+Enter inserts properly indented line above in demo editor
+
+### Fixed
+
+- Single-line forms (`class Foo; end`, `def foo; end`, endless methods) no longer incorrectly indent the next line
+- `end`, `else`, `elsif`, `when`, `rescue`, `ensure` correctly deindent to match their opening keyword at any nesting depth
+- Empty lines inside blocks preserve surrounding indent context
+- Closing delimiters align with their matching opener
+
+### Changed
+
+- Indentation engine rewritten from tree-based `indentNodeProp` to text-based `indentService` for robust handling of incomplete code while typing
+- Updated parse accuracy benchmarks with larger, more representative real-world files
+
+## [0.1.0] - 2026-03-26
+
+### Added
+
+- Initial release
+- Lezer grammar for Ruby with 89 grammar tests
+- **Definitions**: methods (with params, endless `def f(x) = expr`), classes (with inheritance), modules
+- **Control flow**: if/elsif/else, unless, while, until, for/in, case/when, case/in (pattern matching)
+- **Error handling**: begin/rescue/ensure/raise
+- **Strings**: single-quoted, double-quoted with `#{interpolation}`, heredocs (`<<~DELIM`), `%`-literals
+- **Literals**: integers, floats, symbols, character literals, arrays, hashes, regex, nil, true, false
+- **Expressions**: assignment (including `||=`, `&&=`), multiple assignment, method calls, chained calls, binary/unary/ternary operators, lambdas, ranges, conditional modifiers
+- **Blocks**: brace blocks and do/end blocks attached to method calls
+- **Operators**: proper precedence, safe navigation (`&.`), scope resolution (`::`)
+- **Bare method calls**: 25 common Ruby methods (puts, require, attr_reader, include, etc.)
+- **Variables**: local, @instance, @@class, $global, Constants
+- **Comments**: line `#` and block `=begin`/`=end`
+- 5 external tokenizers for context-dependent tokens (regex/division, heredoc/less-than, percent-literal/modulo, symbol/colon, string interpolation)
+- Code folding, bracket closing, keyword autocompletion (31 keywords)
+- Demo page with One Dark theme
+- GitHub Actions CI

README.md

@@ -25,17 +25,17 @@ new EditorView({
 
 ## Real-world parse accuracy
 
-Tested against popular open source Ruby projects:
-
-| Project | Stars | Lines | Accuracy |
-|---------|-------|-------|----------|
-| [Rails](https://github.com/rails/rails) | 56k | 338 | **99.7%** |
-| [Jekyll](https://github.com/jekyll/jekyll) | 49k | 196 | **99.6%** |
-| [Fastlane](https://github.com/fastlane/fastlane) | 40k | 54 | **99.3%** |
-| [Devise](https://github.com/heartcombo/devise) | 24k | 534 | **98.0%** |
-| [Faker](https://github.com/faker-ruby/faker) | 11k | 282 | **97.5%** |
-| [Sidekiq](https://github.com/sidekiq/sidekiq) | 13k | 162 | **97.5%** |
-| [Grape](https://github.com/ruby-grape/grape) | 10k | 75 | **95.3%** |
+Tested against popular open source Ruby projects (large, representative files):
+
+| Project | File | Lines | Accuracy |
+|---------|------|-------|----------|
+| [Fastlane](https://github.com/fastlane/fastlane) | runner.rb | 379 | **91.3%** |
+| [Grape](https://github.com/ruby-grape/grape) | api.rb | 166 | **90.1%** |
+| [Jekyll](https://github.com/jekyll/jekyll) | site.rb | 577 | **88.4%** |
+| [Devise](https://github.com/heartcombo/devise) | devise.rb | 534 | **87.9%** |
+| [Sidekiq](https://github.com/sidekiq/sidekiq) | config.rb | 321 | **87.5%** |
+| [Rails](https://github.com/rails/rails) | query_methods.rb | 2291 | **86.6%** |
+| [Faker](https://github.com/faker-ruby/faker) | internet.rb | 579 | **85.3%** |
 
 ## What's supported
 
@@ -50,21 +50,22 @@ Tested against popular open source Ruby projects:
 - **Bare method calls**: `puts "hello"`, `require "json"`, `attr_reader :name`, `include Comparable` (25 common Ruby methods)
 - **Variables**: local, `@instance`, `@@class`, `$global`, `Constants`
 - **Comments**: line `#` and block `=begin`/`=end`
-- **Editor features**: indentation, code folding, bracket closing, keyword autocompletion (31 keywords)
+- **Editor features**: smart indentation (119 test cases), code folding, bracket closing, keyword autocompletion (31 keywords)
 
 ## Known limitations
 
+- Blank lines inside class/method bodies can produce spurious error nodes (~38% of parse errors)
+- Multi-arg bare method calls (`raise ArgumentError, "msg"`) not fully supported
+- Compound assignment operators (`+=`, `-=`, `|=`) in some contexts
 - Heredoc and `%`-literal bodies are opaque tokens (no interpolation highlighting inside)
-- Hash symbol-key shorthand (`{ name: "Alice" }`) not supported (`:` conflicts with Symbol token when blocks are expressions)
-- Setter method definitions (`def name=(val)`) and subscript access (`arr[0]`) not yet supported
 - `<<` left-shift operator not distinguished from heredoc start
 
 ## Development
 
 ```bash
 npm install          # Install dependencies
 npm run build        # Build grammar + bundle to dist/
-npm test             # Run all 83 grammar tests
+npm test             # Run all 89 grammar tests
 npm run lint         # TypeScript type check
 npm run demo:build   # Build the demo page
 ```

demo/demo.js

@@ -1,4 +1,7 @@
 import {EditorView, basicSetup} from "codemirror"
+import {keymap} from "@codemirror/view"
+import {indentWithTab} from "@codemirror/commands"
+import {getIndentation} from "@codemirror/language"
 import {oneDark} from "@codemirror/theme-one-dark"
 import {ruby} from "../src/index"
 
@@ -73,6 +76,16 @@ new EditorView({
   doc: sampleCode,
   extensions: [
     basicSetup,
+    keymap.of([
+      indentWithTab,
+      {key: "Mod-Shift-Enter", run: (view) => {
+        const line = view.state.doc.lineAt(view.state.selection.main.head)
+        const indent = getIndentation(view.state, line.from)
+        const pad = indent != null && indent > 0 ? " ".repeat(indent) : ""
+        view.dispatch({changes: {from: line.from, insert: pad + "\n"}, selection: {anchor: line.from + pad.length}})
+        return true
+      }},
+    ]),
     ruby(),
     oneDark,
     EditorView.theme({

demo/demo.ts

@@ -1,6 +1,6 @@
 {
   "name": "codemirror-lang-ruby",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Ruby language support for CodeMirror 6, built on a Lezer grammar",
   "type": "module",
   "main": "dist/index.cjs",
@@ -45,8 +45,10 @@
   },
   "devDependencies": {
     "@codemirror/autocomplete": "^6.20.1",
+    "@codemirror/commands": "^6.10.3",
     "@codemirror/language": "^6.0.0",
     "@codemirror/theme-one-dark": "^6.1.3",
+    "@codemirror/view": "^6.40.0",
     "@lezer/common": "^1.0.0",
     "@lezer/generator": "^1.0.0",
     "@lezer/highlight": "^1.0.0",