Ruby Expand Selection & Jump

English documentation is below. 🇯🇵 日本語版は README.ja.md をご覧ください。

Tree-sitter powered VS Code commands that understand Ruby blocks: jump between matching keywords (Vim % style) and grow/shrink selections by Ruby syntax nodes.

Highlights

• Jump instantly between matching do/def/if … end, class/module, etc.
• Landing on else/elsif/when/rescue/ensure takes you to the corresponding end.
• Uses web-tree-sitter with a bundled tree-sitter-ruby.wasm, so comments and literals aren’t mistaken for real keywords.
• Expand and shrink selections along Ruby syntax boundaries. Every expand step is remembered so shrink walks you back to the original caret position.

Commands

Command ID	Title	Description	Default Keybinding (mac / win&linux)
rubyExpandSelection.jump	Ruby: Jump to Matching do/def/if … end	Jump to the paired block keyword (start/end/middle)	⌘⇧5 / Ctrl⇧5
rubyExpandSelection.expandSelection	Ruby: Expand Selection (Tree-sitter)	Expand selection one syntax step using Tree-sitter	⇧⌥→ / Shift+Alt+Right
rubyExpandSelection.shrinkSelection	Ruby: Shrink Selection (Tree-sitter)	Collapse selection by replaying the expand history in reverse	⇧⌥← / Shift+Alt+Left

You can remap the keys from VS Code’s Keyboard Shortcuts screen.

Usage

1. Place the caret anywhere in a Ruby file.
2. Run the command (via keybinding or Command Palette):
   • Jump: run on do, def, if, end, or middle keywords to move to the matching side.
   • Expand Selection: grow the selection outwards by Ruby syntax units.
   • Shrink Selection: step backwards through the same ladder until you return to the starting caret.

Selection example

total = orders.sum do |order|
  order.items.sum { |item| item.price_with_tax(rate) }
end

Place the caret inside price_with_tax and keep pressing Expand Selection to see the syntax-aware ladder:

1. price_with_tax (method name)
2. item.price_with_tax (receiver + method)
3. item.price_with_tax(rate) (full method call)
4. |item| item.price_with_tax(rate) (block body)
5. { |item| item.price_with_tax(rate) } (inner block)
6. order.items.sum { |item| item.price_with_tax(rate) } (chained call with block)
7. |order|\n order.items.sum { |item| item.price_with_tax(rate) } (outer block body)
8. do |order|\n order.items.sum { |item| item.price_with_tax(rate) }\nend (the do–end block)
9. orders.sum do |order|\n order.items.sum { |item| item.price_with_tax(rate) }\nend (method call + block)
10. total = orders.sum do |order|\n order.items.sum { |item| item.price_with_tax(rate) }\nend (full statement)

Hitting Shrink Selection retraces the same ladder back to the original caret. Blocks, arrays, interpolated strings, and other Ruby constructs behave the same way.

Visualizing each expand step

Brackets [ … ] highlight the current selection.

1: order.items.sum { |item| item.[price_with_tax](rate) }
2: order.items.sum { |item| [item.price_with_tax](rate) }
3: order.items.sum { |item| [item.price_with_tax(rate)] }
4: order.items.sum { |item| [|item| item.price_with_tax(rate)] }
5: order.items.sum { [|item| item.price_with_tax(rate)] }
6: [order.items.sum { |item| item.price_with_tax(rate) }]
7: [|order|
     order.items.sum { |item| item.price_with_tax(rate) }]
8: [do |order|
     order.items.sum { |item| item.price_with_tax(rate) }
   end]
9: [orders.sum do |order|
     order.items.sum { |item| item.price_with_tax(rate) }
   end]
10: [total = orders.sum do |order|
      order.items.sum { |item| item.price_with_tax(rate) }
    end]

Jump example

Installation

VS Code Marketplace

Once the listing is live, search for “Ruby Expand Selection & Jump” in the Marketplace to install.

VSIX / local install

1. Download the .vsix from Releases and choose Extensions › … › Install from VSIX.
2. Or clone this repository and run the extension from source (see below).

Development setup

1. Open this folder in VS Code
2. npm install
3. npm run compile
4. Press F5 (Run Extension) and try the commands in the launched Extension Development Host

The tree-sitter/ folder already ships the runtime (tree-sitter.wasm) and Ruby grammar (tree-sitter-ruby.wasm), so no extra build steps are needed.

Testing

Run npm run test to build the extension and execute the Tree-sitter–based jump regression tests.
These tests feed sample while/until/for blocks (with and without inline do) directly through computeBlockTargetOffset, ensuring the jump command keeps working even without VS Code running.

Limitations / roadmap

• Heredocs (<<ID), %q/%Q/%w-style literals, and regex literals are exposed by Tree-sitter as string nodes. This extension currently treats them as opaque strings, so nested Ruby code inside them isn’t inspected.
• Building the syntax tree can take a fraction of a second on very large files the first time you run a command.
• Behaviour ultimately depends on the Ruby grammar provided by Tree-sitter. If you hit issues with newer Ruby syntax, please open an issue.

Feedback and contributions are welcome—feel free to file issues or PRs!